draft-ietf-ipo-carrier-requirements-03.txt   draft-ietf-ipo-carrier-requirements-04.txt 
INTERNET-DRAFT INTERNET-DRAFT
Document: draft-ietf-ipo-carrier-requirements-03.txt Yong Xue Document: draft-ietf-ipo-carrier-requirements-04.txt Yong Xue
Category: Informational (Editor) Category: Informational (Editor)
Expiration Date: December, 2002 WorldCom, Inc Expiration Date: May, 2003 WorldCom, Inc
Monica Lazer Monica Lazer
Jennifer Yates Jennifer Yates
Dongmei Wang Dongmei Wang
AT&T AT&T
Ananth Nagarajan Ananth Nagarajan
Sprint Sprint
Hirokazu Ishimatsu Hirokazu Ishimatsu
Japan Telecom Co., LTD Japan Telecom Co., LTD
Olga Aparicio Olga Aparicio
Cable & Wireless Global Cable & Wireless Global
Steven Wright Steven Wright
Bellsouth Bellsouth
June 2002 November 2002
Carrier Optical Services Requirements Carrier Optical Service Requirements
Status of This Memo Status of This Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. Internet-Drafts are working all provisions of Section 10 of RFC2026. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts. working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or rendered obsolete by other documents and may be updated, replaced, or rendered obsolete by other documents
at any time. It is inappropriate to use Internet-Drafts as reference at any time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
Abstract Abstract
This Internet Draft describes the major carrier's service requirements for the This Internet Draft describes the major carrier's optical service requirements
automatic switched optical networks (ASON) from both an end-user's as well as an for the Automatically Switched Optical Networks (ASON) from both an end-user's
operator's perspectives. Its focus is on the description of the service building as well as an operator's perspectives. Its focus is on the description of the
blocks and service-related control plane functional requirements. The management service building blocks and service-related control plane functional
functions for the optical services and their underlying networks are beyond the requirements. The management functions for the optical services and their
scope of this document and will be addressed in a separate document. underlying networks are beyond the scope of this document and will be addressed
in a separate document.
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Table of Contents Table of Contents
1. Introduction 3 1. Introduction 3
1.1 Justification 4 1.1 Justification 4
1.2 Conventions used in this document 4 1.2 Conventions used in this document 4
1.3 Value Statement 4 1.3 Value Statement 4
1.4 Scope of This Document 5 1.4 Scope of This Document 5
2. Abbreviations 6 2. Abbreviations 6
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8.5 Control Plane Interface to Management Plane 29 8.5 Control Plane Interface to Management Plane 29
8.6 IP and Optical Control Plane Interconnection 29 8.6 IP and Optical Control Plane Interconnection 29
9. Requirements for Signaling, Routing and Discovery 30 9. Requirements for Signaling, Routing and Discovery 30
9.1 Requirements for information sharing over UNI, 9.1 Requirements for information sharing over UNI,
I-NNI and E-NNI 30 I-NNI and E-NNI 30
9.2 Signaling Functions 30 9.2 Signaling Functions 30
9.3 Routing Functions 31 9.3 Routing Functions 31
9.4 Requirements for path selection 32 9.4 Requirements for path selection 32
9.5 Discovery Functions 33 9.5 Discovery Functions 33
10. Requirements for service and control plane 10. Requirements for service and control plane
resiliency 34
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resiliency 34
10.1 Service resiliency 35 10.1 Service resiliency 35
10.2 Control plane resiliency 37 10.2 Control plane resiliency 37
11. Security Considerations 37 11. Security Considerations 37
11.1 Optical Network Security Concerns 37 11.1 Optical Network Security Concerns 37
11.2 Service Access Control 39 11.2 Service Access Control 39
12. Acknowledgements 39 12. Acknowledgements 39
13. References 39 13. References 39
Authors' Addresses 41 Authors' Addresses 41
Appendix: Interconnection of Control Planes 42 Appendix: Interconnection of Control Planes 42
1. Introduction 1. Introduction
Optical transport networks are evolving from the current TDM-based Optical transport networks are evolving from the current TDM-based SONET/SDH
SONET/SDH optical networks as defined by ITU Rec. G.803 [itu-sdh] to optical networks as defined by ANSI T1.105 and ITU Rec. G.803[ansi-sonet, itu-
the emerging WDM-based optical transport networks (OTN) as defined by sdh] to emerging WDM-based optical transport networks (OTN) as defined by ITU
the ITU Rec. G.872 in [itu-otn]. Therefore in the near future, Rec. G.872 in [itu-otn]. Therefore in the near future, carrier optical transport
carrier optical transport networks will consist of a mixture of the networks are expected to consist of a mixture of the SONET/SDH-based sub-
SONET/SDH-based sub-networks and the WDM-based wavelength or fiber networks and the WDM-based wavelength or fiber switched OTN sub-networks. The
switched OTN sub-networks. The OTN networks can be either transparent OTN networks can be either transparent or opaque depending upon if O-E-O
or opaque depending upon if O-E-O functions are utilized within the functions are utilized within the optical networks. Optical networking
sub-networks. Optical networking encompasses the functionalities for encompasses the functionalities for the establishment, transmission,
the establishment, transmission, multiplexing, switching of optical multiplexing and switching of optical connections carrying a wide range of user
connections carrying a wide range of user signals of varying formats signals of varying formats and bit rate. The optical connections in this
and bit rate. document include switched optical path using TDM channel, WADM wavelength or
fiber links.
Some of the challenges for the carriers are bandwidth management and fast Some of the challenges for the carriers are efficient bandwidth management and
service provisioning in such a multi-technology and possibly multi-vendor fast service provisioning in a multi-technology and possibly multi-vendor
networking environment. The emerging and rapidly evolving automatic networking environment. The emerging and rapidly evolving Automatically Switched
switched optical networks or ASON technology [itu-astn, itu-ason] is Optical Network (ASON) technology [itu-astn, itu-ason] is aimed at providing
aimed at providing optical networks with intelligent networking optical networks with intelligent networking functions and capabilities in its
functions and capabilities in its control plane to enable rapid control plane to enable rapid optical connection provisioning, dynamic rerouting
optical connection provisioning, dynamic rerouting as well as as well as multiplexing and switching at different granularity levels, including
multiplexing and switching at different granularity level, including fiber, wavelength and TDM channel. The ASON control plane should not only enable
fiber, wavelength and TDM time slots. The ASON control plane should the new networking functions and capabilities for the emerging OTN networks, but
not only enable the new networking functions and capabilities for the significantly enhance the service provisioning capabilities for the existing
emerging OTN networks, but significantly enhance the service SONET/SDH networks as well.
provisioning capabilities for the existing SONET/SDH networks as
well.
The ultimate goals should be to allow the carriers to quickly and The ultimate goals should be to allow the carriers to automate network resource
dynamically provision network resources and to support network and topology discovery, to quickly and dynamically provision network resources
survivability using ring and mesh-based protection and restoration and circuits, and to support assorted network survivability using ring and
techniques. The carriers see that this new networking platform will mesh-based protection and restoration techniques. The carriers see that this new
create tremendous business opportunities for the network operators networking platform will create tremendous business opportunities for the
and service providers to offer new services to the market, reduce network operators and service providers to offer new services to the market, and
their network operation efficiency (OpEx saving), and in the long run to reduce their network operation cost (OpEx saving), and to
improve their network utilization efficiency (CapEx saving). improve their network utilization efficiency (CapEx saving).
1.1. Justification 1.1. Justification
The charter of the IPO WG calls for a document on "Carrier Optical
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Services Requirements" for IP over Optical networks. This document The charter of the IPO WG calls for a document on "Carrier Optical Service
addresses that aspect of the IPO WG charter. Furthermore, this Requirements" for IP over Optical networks. This document addresses that aspect
document was accepted as an IPO WG document by unanimous agreement at of the IPO WG charter. Furthermore, this document was accepted as an IPO WG
the IPO WG meeting held on March 19, 2001, in Minneapolis, MN, USA. document by unanimous agreement at the IPO WG meeting held on March 19, 2001, in
It presents a carrier and end-user perspective on optical network Minneapolis, MN, USA. It presents a carrier as well as an end-user perspective
services and requirements. on optical network services and requirements.
1.2. Conventions used in this document 1.2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT","SHOULD",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be
document are to be interpreted as described in RFC 2119. interpreted as described in RFC 2119.
1.3. Value Statement 1.3. Value Statement
By deploying ASON technology, a carrier expects to achieve the By deploying ASON technology, a carrier expects to achieve the following
following benefits from both technical and business perspectives: benefits from both technical and business perspectives:
- Automated Discovery: ASON technology will enable automatic network Automated Discovery: ASON technology will enable automatic network Inventory
inventory, topology and resource discovery and maintenance management, topology and resource discovery which eliminates the manual or semi-
which eliminates the manual or semi-manual process for manual process for maintaining the network information database that exist in
maintaining the network information database that exist in most most carrier environment.
carrier environment.
- Rapid Circuit Provisioning: ASON technology will enable the dynamic Rapid Circuit Provisioning: ASON technology will enable the dynamic end-to-end
end-to-end provisioning of the optical connections across the optical provisioning of the optical connections across the optical network by using
network by using standard routing and signaling protocols. standard routing and signaling protocols.
- Enhanced Survivability: ASON technology will enable the network to Enhanced Protection and Restoration: ASON technology will enable the network to
dynamically reroute an optical connection in case of a failure using dynamically reroute an optical connection in case of failure using mesh-based
mesh-based network protection and restoration techniques, which network protection and restoration techniques, which greatly improves the cost-
greatly improves the cost-effectiveness compared to the current line effectiveness compared to the current line and ring protection schemes in the
and ring protection schemes in the SONET/SDH network. SONET/SDH network.
- Service Flexibility: ASON technology will support provisioning of - Service Flexibility: ASON technology will support provisioning of
an assortment of existing and new services such as protocol and bit- an assortment of existing and new services such as protocol and bit-
rate independent transparent network services, and bandwidth-on- rate independent transparent network services, and bandwidth-on-
demand services. demand services.
- Enhanced Interoperability: ASON technology will use a control plane - Enhanced Interoperability: ASON technology will use a control plane
utilizing industry and international standards architecture and utilizing industry and international standards-based architecture and
protocols, which facilitate the interoperability of the optical protocols, which facilitate the interoperability of the optical
network equipment from different vendors. network equipment from different vendors.
In addition, the introduction of a standards-based control plane In addition, the ASON control plane may offer the following potential
offers the following potential benefits: value-added benefits:
- Reactive traffic engineering at optical layer that allows network - Reactive traffic engineering at optical layer that allows network
resources to be dynamically allocated to traffic flow. resources to be dynamically allocated to traffic flow.
- Reduce the need for service providers to develop new operational
support systems (OSS) software for the network control and new service
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- Reduce the need for service providers to develop new operational
support systems software for the network control and new service
provisioning on the optical network, thus speeding up the deployment provisioning on the optical network, thus speeding up the deployment
of the optical network technology and reducing the software of the optical network technology and reducing the software
development and maintenance cost. development and maintenance cost.
- Potential development of a unified control plane that can be used - Potential development of a unified control plane that can be used
for different transport technologies including OTN, SONET/SDH, ATM for different transport technologies including OTN, SONET/SDH, ATM
and PDH. and PDH.
1.4. Scope of this document 1.4. Scope of this document
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suitable to their business model. These building blocks include suitable to their business model. These building blocks include
generic service types, service enabling control mechanisms and generic service types, service enabling control mechanisms and
service control and management functions. service control and management functions.
OIF carrier group has developed a comprehensive set of control plane OIF carrier group has developed a comprehensive set of control plane
requirements for both UNI and NNI [oif-carrier, oif-nnireq] and they requirements for both UNI and NNI [oif-carrier, oif-nnireq] and they
have been used as the base line input to this document. have been used as the base line input to this document.
The fundamental principles and basic set of requirements for the The fundamental principles and basic set of requirements for the
control plane of the automatic switched optical networks have been control plane of the automatic switched optical networks have been
provided in a series of ITU Recommendations under the umbrella of the provided in a series of ITU Recommendations under the umbrella of
ITU ASTN/ASON architectural and functional requirements as listed ITU ASTN/ASON architectural and functional requirements as listed
below: below:
Architecture: Architecture:
- ITU-T Rec. G.8070/Y.1301 (2001), Requirements for the Automatic - ITU-T Rec. G.8070/Y.1301 (2001), Requirements for the Automatic
Switched Transport Network (ASTN)[itu-astn] Switched Transport Network (ASTN)[itu-astn]
- ITU-T Rec. G.8080/Y.1304 (2001), Architecture of the Automatic - ITU-T Rec. G.8080/Y.1304 (2001), Architecture of the Automatic
Switched Optical Network (ASON)[itu-ason] Switched Optical Network (ASON)[itu-ason]
Signaling: Signaling:
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- ITU-T Rec. G.7713/Y.1704 (2001), Distributed Call and Connection - ITU-T Rec. G.7713/Y.1704 (2001), Distributed Call and Connection
Management (DCM)[itu-dcm] Management (DCM)[itu-dcm]
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Routing: Routing:
- ITU-T Draft Rec. G.7715/Y.1706 (2002), Architecture and Requirements for - ITU-T Draft Rec. G.7715/Y.1706 (2002), Architecture and Requirements for
Routing in the Automatically Switched Optical Network [itu-rtg] Routing in the Automatically Switched Optical Network [itu-rtg]
Discovery: Discovery:
- ITU-T Rec. G.7714/Y.1705 (2001), Generalized Automatic Discovery - ITU-T Rec. G.7714/Y.1705 (2001), Generalized Automatic Discovery
[itu-disc] [itu-disc]
Link Management: Link Management:
- ITU-T Rec. G.7716/Y.1707 (2003), Link Resource Management for ASON - ITU-T Rec. G.7716/Y.1707 (2003), Link Resource Management for ASON
(work in progress)[itu-lm] (work in progress)[itu-lm]
Signaling Communication Network: Signaling Communication Network:
- ITU-T Rec. G.7712/Y.1703 (2001), Architecture and Specification of - ITU-T Rec. G.7712/Y.1703 (2001), Architecture and Specification of
Data Communication Network [itu-dcn] Data Communication Network [itu-dcn]
This document provides further detailed requirements based on this ASTN/ASON This document provides further detailed requirements based on the ASTN/ASON
framework. In addition, even though we consider IP a major framework. In addition, even though for IP over Optical we consider IP as a
client to the optical network in this document, the same requirements major client to the optical network in this document, the same requirements
and principles should be equally applicable to non-IP clients such as and principles should be equally applicable to non-IP clients such as
SONET/SDH, ATM, ITU G.709, Ethernet, etc. The general architecture for IP over SONET/SDH, ATM, ITU G.709, Ethernet, etc. The general architecture for IP over
Optical is described in the IP over Optical framework document [ipo-frame] Optical is described in the IP over Optical framework document [ipo-frame]
2. Abbreviations 2. Abbreviations
ASON Automatic Switched Optical Networking ASON Automatic Switched Optical Networking
ASTN Automatic Switched Transport Network ASTN Automatic Switched Transport Network
CAC Connection Admission Control CAC Connection Admission Control
NNI Node-to-Node Interface NNI Node-to-Node Interface
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NE Network Element NE Network Element
OTN Optical Transport Network OTN Optical Transport Network
CNE Customer/Client Network Element CNE Customer/Client Network Element
ONE Optical Network Element ONE Optical Network Element
OLS Optical Line System OLS Optical Line System
PI Physical Interface PI Physical Interface
SLA Service Level Agreement SLA Service Level Agreement
SCN Signaling Communication Network SCN Signaling Communication Network
3. General Requirements 3. General Requirements
In order to provide the carriers with flexibility and control of the optical
In this section, a number of generic requirements related to the networks, the following set of architectural requirements are essential.
service control and management functions are discussed.
3.1. Separation of Networking Functions 3.1. Separation of Networking Functions
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A fundamental architectural principle of the ASON network A fundamental architectural principle of the ASON network
is to segregate the networking functions within is to segregate the networking functions within
each layer network into three logical functional planes: control each layer network into three logical functional planes: control
plane, data plane and management plane. They are responsible for plane, data plane and management plane. They are responsible for
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providing network control functions, data transmission functions and providing network control functions, data transmission functions and
network management functions respectively. The crux of the ASON network management functions respectively. The crux of the ASON
network is the networking intelligence that contains automatic network is the networking intelligence that contains automatic
routing, signaling and discovery functions to automate the network routing, signaling and discovery functions to automate the network
control functions. control functions.
Control Plane: includes the functions related to networking control Control Plane: includes the functions related to networking control
capabilities such as routing, signaling, and policy control, as well capabilities such as routing, signaling, and policy control, as well
as resource and service discovery. These functions are automated. as resource and service discovery. These functions are automated.
Data Plane (transport plane): includes the functions related to Data Plane (Transport Plane): includes the functions related to
bearer channels and signal transmission. bearer channels and signal transmission.
Management Plane: includes the functions related to the management Management Plane: includes the functions related to the management
functions of network element, networks and network resources and functions of network element, networks and network resources and
services. These functions are less automated as compared to control services. These functions are less automated as compared to control
plane functions. plane functions.
Each plane consists of a set of interconnected functional or control Each plane consists of a set of interconnected functional or control
entities, physical or logical, responsible for providing the entities, physical or logical, responsible for providing the
networking or control functions defined for that network layer. networking or control functions defined for that network layer.
Each plane has clearly defined functional responsibilities. However, the Each plane has clearly defined functional responsibilities. However, the
management plane is responsible for the management of both control and data management plane is responsible for the management of both control and data
planes, thus playing an authoritative role in overall control and management planes, thus playing an authoritative role in overall control and management
functions as discussed in Section 8. functions as discussed in Section 8.
The separation of the control plane from both the data and management The separation of the control plane from both the data and management
plane is beneficial to the carriers in that it: plane is beneficial to the carriers in that it:
- Allows equipment vendors to have a modular system design that will - Allows equipment vendors to have a modular system design that will
be more reliable and maintainable thus reducing the overall systems be more reliable and maintainable.
ownership and operation cost.
- Allows carriers to have the flexibility to choose a third party - Allows carriers to have the flexibility to choose a third party
vendor control plane software systems as its control plane solution vendor control plane software systems as the control plane solution
for its switched optical network. for its switched optical network.
- Allows carriers to deploy a unified control plane and - Allows carriers to deploy a unified control plane and
OSS/management systems to manage and control different types of OSS/management systems to manage and control different types of
transport networks it owns. transport networks it owns.
- Allows carriers to use a separate control network specially - Allows carriers to use a separate control network specially
designed and engineered for the control plane communications. designed and engineered for the control plane communications.
The separation of control, management and transport function is The separation of control, management and transport function is
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required and it shall accommodate both logical and physical level required and it shall accommodate both logical and physical level
separation. separation. The logical separation refers to functional separation while
physical separation refers to the case where the control, management and
transport functions physically reside in different equipment or locations.
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Note that it is in contrast to the IP network where the control Note that it is in contrast to the IP network where the control
messages and user traffic are routed and switched based on the same messages and user traffic are routed and switched based on the same
network topology due to the associated in-band signaling nature of network topology due to the associated in-band signaling nature of
the IP network. the IP network.
When the physical separation is allowed between the control and data plane, a When the physical separation is allowed between the control and data plane, a
standardized interface and control protocol (e.g. GSMP [ietf-gsmp]) should be standardized interface and control protocol (e.g. GSMP [ietf-gsmp]) should be
supported. supported.
3.2. Separation of call and connection control 3.2. Separation of call and connection control
To support many enhanced optical services, such as scheduled To support many enhanced optical services, such as scheduled
bandwidth on demand, diversity circuit provisioning and bundled connections, a bandwidth on demand, diverse circuit provisioning and bundled connections, a
call model based on the separation of the, all control and connection control is call model based on the separation of call control and connection control is
essential. essential.
The call control is responsible for the end-to-end session The call control is responsible for the end-to-end session
negotiation, call admission control and call state maintenance while negotiation, call admission control and call state maintenance while
connection control is responsible for setting up the connections connection control is responsible for setting up the connections
associated with a call across the network. A call can correspond to associated with a call across the network. A call can correspond to
zero, one or more connections depending upon the number of zero, one or more connections depending upon the number of
connections needed to support the call. connections needed to support the call.
The existence of the connection depends upon the existence of its The existence of the connection depends upon the existence of its
associated call session and connection can be deleted and re- associated call session and connection can be deleted and re-
established while still keeping the call session up. established while still keeping the call session up.
The call control shall be provided at an ingress port or gateway port The call control shall be provided at an ingress port or gateway port
to the network such as UNI and E-NNI [ see Section 5 for definition]. to the network such as UNI and E-NNI [ see Section 5 for definition].
The connection control is provided at the originating node of the circuit as
well as on each link along the path.
The control plane shall support the separation of the call control The control plane shall support the separation of the call control
from the connection control. from the connection control.
The control plane shall support call admission control on call setup The control plane shall support call admission control on call setup
and connection admission control on connection setup. and connection admission control on connection setup.
3.3. Network and Service Scalability 3.3. Network and Service Scalability
Although some specific applications or networks may be on a small Although some specific applications or networks may be on a small
scale, the control plane protocol and functional capabilities shall scale, the control plane protocol and functional capabilities shall
support large-scale networks. support large-scale networks.
In terms of the scale and complexity of the future optical network, In terms of the scale and complexity of the future optical network,
the following assumption can be made when considering the scalability the following assumption can be made when considering the scalability
and performance that are required of the optical control and and performance that are required of the optical control and
management functions. management functions.
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- There may be up to thousands of OXC nodes and the same or higher - There may be up to thousands of OXC nodes and the same or higher
order of magnitude of OADMs per carrier network. order of magnitude of OADMs per carrier network.
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- There may be up to thousands of terminating ports/wavelength per - There may be up to thousands of terminating ports/wavelength per
OXC node. OXC node.
- There may be up to hundreds of parallel fibers between a pair of - There may be up to hundreds of parallel fibers between a pair of
OXC nodes. OXC nodes.
- There may be up to hundreds of wavelength channels transmitted on - There may be up to hundreds of wavelength channels transmitted on
each fiber. each fiber.
In relation to the frequency and duration of the optical connections: As for the frequency and duration of the optical connections:
- The expected end-to-end connection setup/teardown time should be in - The expected end-to-end connection setup/teardown time should be in
the order of seconds, preferably less. the order of seconds, preferably less.
- The expected connection holding times should be in the order of - The expected connection holding times should be in the order of
minutes or greater. minutes or greater.
- There may be up to millions of simultaneous optical connections - There may be up to millions of simultaneous optical connections
switched across a single carrier network. switched across a single carrier network.
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The service building blocks are comprised of a well-defined set of The service building blocks are comprised of a well-defined set of
capabilities and a basic set of control and management functions. capabilities and a basic set of control and management functions.
These capabilities and functions should support a basic set of These capabilities and functions should support a basic set of
services and enable a carrier to build enhanced services through services and enable a carrier to build enhanced services through
extensions and customizations. Examples of the building blocks extensions and customizations. Examples of the building blocks
include the connection types, provisioning methods, control include the connection types, provisioning methods, control
interfaces, policy control functions, and domain internetworking interfaces, policy control functions, and domain internetworking
mechanisms, etc. mechanisms, etc.
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4. Service Model and Applications 4. Service Model and Applications
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A carrier's optical network supports multiple types of service A carrier's optical network supports multiple types of service
models. Each service model may have its own service operations, models. Each service model may have its own service operations,
target markets, and service management requirements. target markets, and service management requirements.
4.1. Service and Connection Types 4.1. Service and Connection Types
The optical network is primarily offering optical paths that are The optical network is primarily offering optical paths that are
fixed bandwidth connections between two client network elements, such fixed bandwidth connections between two client network elements, such
as IP routers or ATM switches, established across the optical as IP routers or ATM switches, established across the optical
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The point-to-point connections are the primary concerns of the carriers. In this The point-to-point connections are the primary concerns of the carriers. In this
case, the following three types of network case, the following three types of network
connections based on different connection set-up control methods connections based on different connection set-up control methods
shall be supported: shall be supported:
- Permanent connection (PC): Established hop-by-hop directly on each - Permanent connection (PC): Established hop-by-hop directly on each
ONE along a specified path without relying on the network routing and ONE along a specified path without relying on the network routing and
signaling capability. The connection has two fixed end-points and signaling capability. The connection has two fixed end-points and
fixed cross-connect configuration along the path and will stays fixed cross-connect configuration along the path and will stays
permanently until it is deleted. This is similar to the concept of permanently until it is deleted. This is similar to the concept of
PVC in ATM. PVC in ATM and there is no automatic re-routing capability.
- Switched connection (SC): Established through UNI signaling - Switched connection (SC): Established through UNI signaling
interface and the connection is dynamically established by network interface and the connection is dynamically established by network
using the network routing and signaling functions. This is similar to using the network routing and signaling functions. This is similar to the
the concept of SVC in ATM. concept of SVC in ATM.
- Soft permanent connection (SPC): Established by specifying two PC - Soft permanent connection (SPC): Established by specifying two PC
at end-points and let the network dynamically establishes a SC at end-points and let the network dynamically establishes a SC
connection in between. This is similar to the SPVC concept in ATM. connection in between. This is similar to the SPVC concept in ATM.
The PC and SPC connections should be provisioned via management plane The PC and SPC connections should be provisioned via management plane
to control interface and the SC connection should be provisioned via to control interface and the SC connection should be provisioned via
signaled UNI interface. signaled UNI interface.
Note that even though automated rapid optical connection provisioning Note that even though automated rapid optical connection provisioning
is required, the carriers expect the majority of provisioned is required, the carriers expect the majority of provisioned
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circuits, at least in short term, to have a long lifespan ranging circuits, at least in short term, to have a long lifespan ranging
from months to years. from months to years.
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In terms of service provisioning, some carriers may choose to perform In terms of service provisioning, some carriers may choose to perform
testing prior to turning over to the customer. testing prior to turning over to the customer.
4.2. Examples of Common Service Models 4.2. Examples of Common Service Models
Each carrier may define its own service model based on it business Each carrier may define its own service model based on it business
strategy and environment. The following are three example service strategy and environment. The following are three example service
models that carriers may use. models that carriers may use.
4.2.1. Provisioned Bandwidth Service (PBS) 4.2.1. Provisioned Bandwidth Service (PBS)
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- Relies on network or client intelligence for connection set-up - Relies on network or client intelligence for connection set-up
depending upon the control plane interconnection model used. depending upon the control plane interconnection model used.
4.2.3. Optical Virtual Private Network (OVPN) 4.2.3. Optical Virtual Private Network (OVPN)
The OVPN model provides virtual private network at the optical layer The OVPN model provides virtual private network at the optical layer
between a specified set of user sites. It has the following between a specified set of user sites. It has the following
characteristics: characteristics:
- Customers contract for specific set of network resources such as - Customers contract for specific set of network resources such as
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optical connection ports, wavelengths, etc. optical connection ports, wavelengths, etc.
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- Closed User Group (CUG) concept is supported as in normal VPN. - Closed User Group (CUG) concept is supported as in normal VPN.
- Optical connection can be of PC, SPC or SC type depending upon the - Optical connection can be of PC, SPC or SC type depending upon the
provisioning method used. provisioning method used.
- An OVPN site can request dynamic reconfiguration of the connections - An OVPN site can request dynamic reconfiguration of the connections
between sites within the same CUG. between sites within the same CUG.
- A customer may have visibility and control of network resources up - A customer may have visibility and control of network resources up
to the extent allowed by the customer service contract. to the extent allowed by the customer service contract.
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At a minimum, the PBS, BDS and OVPN service models described above At a minimum, the PBS, BDS and OVPN service models described above
shall be supported by the control functions. shall be supported by the control functions.
5. Network Reference Model 5. Network Reference Model
This section discusses major architectural and functional components This section discusses major architectural and functional components
of a generic carrier optical network, which will provide a reference of a generic carrier optical network, which will provide a reference
model for describing the requirements for the control and management model for describing the requirements for the control and management
of carrier optical services. of carrier optical services.
5.1. Optical Networks and Subnetworks 5.1. Optical Networks and Sub-networks
As mentioned before, there are two main types of optical networks As mentioned before, there are two main types of optical networks
that are currently under consideration: SDH/SONET network as defined that are currently under consideration: SDH/SONET network as defined
in ITU Rec. G.803, and OTN as defined in ITU Rec. G.872. in ITU Rec. G.803, and OTN as defined in ITU Rec. G.872.
In the current SONET/SDH-based optical network, digital cross-connects (DXC) and In the current SONET/SDH-based optical network, digital cross-connects (DXC) and
add-drop multiplexer (ADM) and line multiplexer terminal (LMT) are connected in add-drop multiplexer (ADM) and line multiplexer terminal (LMT) are connected in
ring or linear topology. Similarly, we assume an OTN is composed of a set of ring or linear topology. Similarly, we assume an OTN is composed of a set of
optical cross-connects (OXC) and optical add-drop multiplexer (OADM) which are optical cross-connects (OXC) and optical add-drop multiplexer (OADM) which is
interconnected in a general mesh topology using DWDM optical line systems (OLS). interconnected in a general mesh topology using DWDM optical line systems (OLS).
It is often convenient for easy discussion and description to treat It is often convenient for easy discussion and description to treat
an optical network as an subnetwork cloud, in which the details of an optical network as an sub-network cloud, in which the details of
the network become less important, instead focus is on the function the network become less important, instead focus is on the function
and the interfaces the optical network provides. In general, a and the interfaces the optical network provides. In general, a
subnetwork can be defined as a set of access points on the network subnetwork can be defined as a set of access points on the network
boundary and a set of point-to-point optical connections between boundary and a set of point-to-point optical connections between
those access points. those access points.
5.2. Network Interfaces 5.2. Control Domains and Interfaces
A generic carrier network reference model describes a multi-carrier A generic carrier network reference model describes a multi-carrier
network environment. Each individual carrier network can be further network environment. Each individual carrier network can be further
partitioned into domains or sub-networks based on administrative, partitioned into sub-networks or administrative domains based on administrative,
technological or architectural reasons. The demarcation between technological or architectural reasons. This partition can be recursive.
(sub)networks can be either logical or physical and consists of a Similarly, a network can be partitioned into control domains that match the
set of reference points identifiable in the optical network. From the administrative domains and are controlled by a single administrative policy.
control plane perspective, these reference points define a set of The control domains can be recursively divided into sub-domains to form control
hierarchy for scalability. The control domain concept can be applied to routing,
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signaling and protection & restoration to form an autonomous control function
domain.
The demarcation between domains can be either logical or physical and consists
of a set of reference points identifiable in the optical network. >From the
control plane perspective, these reference points define a set of
control interfaces in terms of optical control and management control interfaces in terms of optical control and management
functionality. The figure 1 is an illustrative diagram for this. functionality. The figure 1 is an illustrative diagram for this.
+---------------------------------------+ +---------------------------------------+
| single carrier network | | single carrier network |
+--------------+ | | +--------------+ | |
| | | +------------+ +------------+ | |Customer | | +------------+ +------------+ |
|IP | | | | | | | |IP | | | | | | |
|Network +--UNI | + Optical +--UNI--+ Carrier IP | | |Network +--UNI--+ + Optical +--UNI--+CarrierĂs IP| |
| | | | Subnetwork | | network | | | | | | Subnetwork | | network | |
+--------------+ | | (Domain A) +--+ | | | +--------------+ | | (Domain A) +--+ | | |
| +------+-----+ | +------+-----+ | | +------+-----+ | +------+-----+ |
| | | | | | | | | |
| I-NNI E-NNI UNI | | I-NNI E-NNI UNI |
+--------------+ | | | | | +--------------+ | | | | |
| | | +------+-----+ | +------+-----+ | |Customer | | +------+-----+ | +------+-----+ |
|IP +--UNI | + | +----+ | | |IP +--UNI--+ + | +----+ | |
|Network | | | Optical | | Optical | | |Network | | | Optical | | Optical | |
| | | | Subnetwork +-E-NNI-+ Subnetwork | | | | | | Subnetwork +-E-NNI-+ Subnetwork | |
+--------------+ | | (Domain A) | | (Domain B) | | +--------------+ | | (Domain A) | | (Domain B) | |
| +------+-----+ +------+-----+ | | +------+-----+ +------+-----+ |
| | | | | | | |
+---------------------------------------+ +---------------------------------------+
UNI E-NNI UNI E-NNI
| | | |
+------+-------+ +-------+--------+ +------+-------+ +-------+--------+
| | | | | | | |
| Other Client | | Other Carrier | | Other Client | | Other Carrier |
|Network | | Network | |Network | | Network |
| (ATM/SONET) | | | | (ATM/SONET) | | |
+--------------+ +----------------+ +--------------+ +----------------+
Figure 1 Generic Carrier Network Reference Model Figure 1 Generic Carrier Network Reference Model
A network can be partitioned into control domains that match the administrative
domains and is controlled under a single administrative policy. The control
domains can be recursively divided into sub-domains to form control hierarchy
for scalability. The control domain concept can be applied to routing, signaling
and protection & restoration to form an autonomous control function domain.
The network interfaces encompass two aspects of the networking The network interfaces encompass two aspects of the networking
functions: user data plane interface and control plane interface. The functions: user data plane interface and control plane interface. The
former concerns about user data transmission across the physical former concerns about user data transmission across the physical
network interface and the latter concerns about the control message network interface and the latter concerns about the control message
exchange across the network interface such as signaling, routing, exchange across the network interface such as signaling, routing,
etc. We call the former physical interface (PI) and the latter etc. We call the former physical interface (PI) and the latter
control interface. Unless otherwise stated, the control control interface. Unless otherwise stated, the control
interface is assumed in the remaining of this document. interface is assumed in the remaining of this document.
5.2.1. Control Plane Interfaces 5.2.1. Control Plane Interfaces
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Control interface defines a relationship between two connected Control interface defines a relationship between two connected
network entities on both sides of the interface. For each control network entities on both sides of the interface. For each control
interface, we need to define the architectural function that each side interface, we need to define the architectural function that each side
plays and a controlled set of information that can be exchanged plays and a controlled set of information that can be exchanged
across the interface. The information flowing over this logical across the interface. The information flowing over this logical
interface may include, but not limited to: interface may include, but not limited to:
- Endpoint name and address - Interface endpoint name and address
- Reachability/summarized network address information - Reachability/summarized network address information
- Topology/routing information - Topology/routing information
- Authentication and connection admission control information - Authentication and connection admission control information
- Connection management signaling messages - Connection management signaling messages
- Network resource control information - Network resource control information
Different types of the interfaces can be defined for the network Different types of the interfaces can be defined for the network
control and architectural purposes and can be used as the network control and architectural purposes and can be used as the network
reference points in the control plane. In this document, the reference points in the control plane. In this document, the
following set of interfaces are defined as shown in Figure 1. The following set of interfaces is defined as shown in Figure 1.
User-Network Interface (UNI) is a bi-directional control interface User-Network Interface (UNI): is a bi-directional control interface
between service requester and service provider control entities. The between service requester and service provider control entities. The
service request control entity resides outside the carrier network service request control entity resides outside the carrier network
control domain. control domain.
The Network-Network/Node-Node Interface (NNI) is a bi-directional signaling Network-Network/Node-Node Interface (NNI): is a bi-directional signaling
interface between two optical network elements or sub-networks. interface between two optical network elements or sub-networks.
We differentiate between internal NNI (I-NNI) and external NNI (E-NNI) as We differentiate between internal NNI (I-NNI) and external NNI (E-NNI) as
follows: follows:
- E-NNI: A NNI interface between two control plane entities belonging - E-NNI: A NNI interface between two control plane entities belonging
to different control domains. to different control domains.
- I-NNI: A NNI interface between two control plane entities within - I-NNI: A NNI interface between two control plane entities within
the same control domain in the carrier network. the same control domain in the carrier network.
It should be noted that it is quite common to use I-NNI between two Different types of interface, internal vs. external, have different implied
sub-networks within the same carrier network if they belong to trust relationship for security and access control purposes. The trust
different control domains. Different types of interface, internal vs. relationship is not binary, instead a policy-based control mechanism need to be
external, have different implied trust relationship for security and in place to restrict the type and amount of information that can flow cross each
access control purposes. The trust relationship is not binary, instead a type of interfaces depending the carrier's service and business requirements.
policy-based control mechanism need to be in place to restrict the
type and amount of information that can flow cross each type of
interfaces depending the carrier's service and business requirements.
Generally, two networks have a fully trusted relationship if they belong to Generally, two networks have a fully trusted relationship if they belong to
the same administrative domain, in this case, the control information exchange the same administrative domain, in this case, the control information exchange
across the control interface between them should be unlimited. Otherwise, the across the control interface between them should be unlimited. Otherwise, the
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type and amount of the control information that can go across the information type and amount of the control information that can go across the information
should be constrained by the administrative policy. should be constrained by the administrative policy.
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An example of fully trusted interface is an I-NNI between two optical An example of fully trusted interface is an I-NNI between two optical
network elements in a single control domain. Non-trusted interface network elements in a single control domain. Non-trusted interface
examples include an E-NNI between two different carriers or a UNI examples include an E-NNI between two different carriers or a UNI
interface between a carrier optical network and its customers. The trust level interface between a carrier optical network and its customers. The trust level
can be different for the non-trusted UNI or E-NNI interface depending upon if it can be different for the non-trusted UNI or E-NNI interface depending upon if it
within the carrier or not. In general, intra-carrier E-NNI has higher trust within the carrier or not. In general, intra-carrier E-NNI has higher trust
level than inter-carrier E-NNI; similarly UNI internal to the carrier (private level than inter-carrier E-NNI.
UNI) has higher trust level than UNI external to the carrier (public UNI).
The control plane shall support the UNI and NNI interface described The control plane shall support the UNI and NNI interface described
above and the interfaces shall be configurable in terms of the type above and the interfaces shall be configurable in terms of the type
and amount of control information exchange and their behavior shall and amount of control information exchange and their behavior shall
be consistent with the configuration (i.e., external versus internal be consistent with the configuration (i.e., external versus internal
interfaces). interfaces).
5.3. Intra-Carrier Network Model 5.3. Intra-Carrier Network Model
Intra-carrier network model concerns the network service control and Intra-carrier network model concerns the network service control and
management issues within networks owned by a single carrier. management issues within networks owned by a single carrier.
5.3.1. Multiple Sub-networks 5.3.1. Multiple Sub-networks
Without loss of generality, the optical network owned by a carrier Without loss of generality, the optical network owned by a carrier
service operator can be depicted as consisting of one or more optical service operator can be depicted as consisting of one or more optical
sub-networks interconnected by direct optical links. There may be sub-networks interconnected by direct optical links. There may be
many different reasons for more than one optical sub-networks It may many different reasons for more than one optical sub-network. It may
be the result of using hierarchical layering, different technologies be the result of using hierarchical layering, different technologies
across access, metro and long haul (as discussed below), or a result across access, metro and long haul (as discussed below), or a result
of business mergers and acquisitions or incremental optical network of business mergers and acquisitions or incremental optical network
technology deployment by the carrier using different vendors or technology deployment by the carrier using different vendors or
technologies. technologies.
A sub-network may be a single vendor and single technology network. A sub-network may be a single vendor and single technology network.
But in general, the carrier's optical network is heterogeneous in But in general, the carrier's optical network is heterogeneous in
terms of equipment vendor and the technology utilized in each sub- terms of equipment vendor and the technology utilized in each sub-
network. network.
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Few carriers have end-to-end ownership of the optical networks. Even Few carriers have end-to-end ownership of the optical networks. Even
if they do, access, metro and long-haul networks often belong to if they do, access, metro and long-haul networks often belong to
different administrative divisions as separate optical sub-networks. different administrative divisions as separate optical sub-networks.
Therefore Inter-(sub)-networks interconnection is essential in terms Therefore Inter-(sub)-networks interconnection is essential in terms
of supporting the end-to-end optical service provisioning and of supporting the end-to-end optical service provisioning and
management. The access, metro and long-haul networks may use management. The access, metro and long-haul networks may use
different technologies and architectures, and as such may have different technologies and architectures, and as such may have
different network properties. different network properties.
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In general, end-to-end optical connectivity may easily cross multiple In general, end-to-end optical connectivity may easily cross multiple
sub-networks with the following possible scenarios: sub-networks with the following possible scenarios:
Access -- Metro -- Access Access -- Metro -- Access
Access - Metro -- Long Haul -- Metro - Access Access - Metro -- Long Haul -- Metro - Access
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5.4. Inter-Carrier Network Model 5.4. Inter-Carrier Network Model
The inter-carrier model focuses on the service and control aspects The inter-carrier model focuses on the service and control aspects
between different carrier networks and describes the internetworking between different carrier networks and describes the internetworking
relationship between them. relationship between them.
Inter-carrier interconnection provides for connectivity between Inter-carrier interconnection provides for connectivity between
optical network operators. To provide the global reach end-to-end optical network operators. To provide the global reach end-to-end
optical services, optical service control and management between optical services, optical service control and management between
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The intra-carrier and inter-carrier models have different implied control The intra-carrier and inter-carrier models have different implied control
constraints. For example, in the intra-carrier model, the address for routing constraints. For example, in the intra-carrier model, the address for routing
and signaling only need to be unique with the carrier while the inter-carrier and signaling only need to be unique with the carrier while the inter-carrier
model requires the address to be globally unique. model requires the address to be globally unique.
In the intra-carrier network model, the network itself forms the largest control In the intra-carrier network model, the network itself forms the largest control
domain within the carrier network. This domain is usually partitioned into domain within the carrier network. This domain is usually partitioned into
multiple sub-domains, either flat or in hierarchy. The UNI and E-NNI interfaces multiple sub-domains, either flat or in hierarchy. The UNI and E-NNI interfaces
are internal to the carrier network, therefore higher trust level is assumed. are internal to the carrier network, therefore higher trust level is assumed.
Because of this, direct signaling between domains and summarized topology and Because of this, direct signaling between domains and summarized topology and
resource information exchanged can be allowed across the private UNI or intra- resource information exchanged can be allowed across the internal UNI or intra-
carrier E-NNI interfaces. carrier E-NNI interfaces.
In the inter-carrier network model, each carrier's optical network is In the inter-carrier network model, each carrier's optical network is
a separate administrative domain. Both the UNI interface between the a separate administrative domain. Both the UNI interface between the
user and the carrier network and the NNI interface between two user and the carrier network and the NNI interface between two
carrier's networks are crossing the carrier's administrative boundary carrier's networks are crossing the carrier's administrative boundary
and therefore are by definition external interfaces. and therefore are by definition external interfaces.
In terms of control information exchange, the topology information In terms of control information exchange, the topology information
shall not be allowed to cross both E-NNI and UNI interfaces. shall not be allowed to cross both E-NNI and UNI interfaces.
6. Optical Service User Requirements 6. Optical Service User Requirements
This section describes the user requirements for optical services, This section describes the user requirements for optical services,
which in turn impose the requirements on service control and which in turn impose the requirements on service control and
management for the network operators. The user requirements reflect management for the network operators. The user requirements reflect
the perception of the optical service from a user's point of view. the perception of the optical service from a user's point of view.
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6.1. Common Optical Services 6.1. Common Optical Services
The basic unit of an optical transport service is fixed-bandwidth The basic unit of an optical transport service is fixed-bandwidth
optical connectivity between parties. However different services are optical connectivity between applications. However different services are
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created based on its supported signal characteristics (format, bit created based on its supported signal characteristics (format, bit
rate, etc), the service invocation methods and possibly the rate, etc), the service invocation methods and possibly the
associated Service Level Agreement (SLA) provided by the service associated Service Level Agreement (SLA) provided by the service
provider. provider.
At present, the following are the major optical services provided in At present, the following are the major optical services provided in
the industry: the industry:
- SONET/SDH, with different degrees of transparency - SONET/SDH, with different degrees of transparency
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The control plane shall provide the carrier with the capability The control plane shall provide the carrier with the capability
functionality to provision, control and manage all the services functionality to provision, control and manage all the services
listed above. listed above.
6.2. Bearer Interface Types 6.2. Bearer Interface Types
All the bearer interfaces implemented in the ONE shall be supported All the bearer interfaces implemented in the ONE shall be supported
by the control plane and associated signaling protocols. by the control plane and associated signaling protocols.
Y. Xue et al The signaling shall support the following interface types
The following interface types shall be supported by the signaling
protocol: protocol:
- SDH/SONET - SDH/SONET
- 1 Gb Ethernet, 10 Gb Ethernet (WAN mode) Y. Xue et al
- 10 M/100 M/1 G/10 Gb (LAN mode) Ethernet
- FC-N (N= 12, 50, 100, or 200) for Fiber Channel services - Ethernet
- FC-N for Fiber Channel services
- OTN (G.709) - OTN (G.709)
- PDH - PDH
- APON, E-PON - APON and EPON
- ESCON and FICON - ESCON and FICON
6.3. Optical Service Invocation 6.3. Optical Service Invocation
As mentioned earlier, the methods of service invocation play an As mentioned earlier, the methods of service invocation play an
important role in defining different services. important role in defining different services.
6.3.1. Provider-Controlled Service Provisioning
6.3.1. Provider-Initiated Service Provisioning
In this scenario, users forward their service request to the provider In this scenario, users forward their service request to the provider
via a well-defined service management interface. All connection via a well-defined service management interface. All connection
management operations, including set-up, release, query, or management operations, including set-up, release, query, or
modification shall be invoked from the management plane. modification shall be invoked from the management plane. This provisioning
method is for PC and SPC connections.
6.3.2. User-Initiated Service Provisioning 6.3.2. User-Initiated Service Provisioning
In this scenario, users forward their service request to the provider In this scenario, users forward their service request to the provider
via a well-defined UNI interface in the control plane (including via a well-defined UNI interface in the control plane (including
proxy signaling). All connection management operation requests, proxy signaling). All connection management operation requests,
including set-up, release, query, or modification shall be invoked including set-up, release, query, or modification shall be invoked
from directly connected user devices, or its signaling representative from directly connected user devices, or its signaling proxy.
(such as a signaling proxy). This provisioning method is for SC connection.
6.3.3. Call set-up requirements 6.3.3. Call set-up requirements
In summary the following requirements for the control plane have been In summary the following requirements for the control plane have been
identified: identified:
- The control plane shall support action result codes as responses to - The control plane shall support action result codes as responses to
any requests over the control interfaces. any requests over the control interfaces.
- The control plane shall support requests for call set-up, subject - The control plane shall support requests for call set-up, subject
to policies in effect between the user and the network. to policies in effect between the user and the network.
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decision to accept or reject call set-up requests from the source decision to accept or reject call set-up requests from the source
client's device. client's device.
- The control plane shall support requests for call set-up and - The control plane shall support requests for call set-up and
deletion across multiple (sub)networks. deletion across multiple (sub)networks.
- NNI signaling shall support requests for call set-up, subject to - NNI signaling shall support requests for call set-up, subject to
policies in effect between the (sub)networks. policies in effect between the (sub)networks.
- Call set-up shall be supported for both uni-directional and bi- - Call set-up shall be supported for both uni-directional and bi-
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directional connections. directional connections.
- Upon call request initiation, the control plane shall generate a - Upon call request initiation, the control plane shall generate a
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network unique Call-ID associated with the connection, to be used for network unique Call-ID associated with the connection, to be used for
information retrieval or other activities related to that connection. information retrieval or other activities related to that connection.
- CAC shall be provided as part of the call control functionality. It - CAC shall be provided as part of the call control functionality. It
is the role of the CAC function to determine if the call can be is the role of the CAC function to determine if the call can be
allowed to proceed based on resource availability and authentication. allowed to proceed based on resource availability and authentication.
- Negotiation for call set-up for multiple service level options - Negotiation for call set-up for multiple service level options
shall be supported. shall be supported.
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- The control plane shall report to the management plane, the - The control plane shall report to the management plane, the
success/failures of a call request. success/failures of a call request.
- Upon a connection request failure, the control plane shall report - Upon a connection request failure, the control plane shall report
to the management plane a cause code identifying the reason for the to the management plane a cause code identifying the reason for the
failure and all allocated resources shall be released. A negative failure and all allocated resources shall be released. A negative
acknowledgment shall be returned to the source. acknowledgment shall be returned to the source.
- Upon a connection request success a positive acknowledgment shall - Upon a connection request success a positive acknowledgment shall
be returned to the source when a connection has been successfully be returned to the source when a connection has been successfully
established, the control plane shall be notified. established.
- The control plane shall support requests for call release by Call- - The control plane shall support requests for call release by Call-
ID. ID.
- The control plane shall allow any end point or any intermediate - The control plane shall allow any end point or any intermediate
node to initiate call release procedures. node to initiate call release procedures.
- Upon call release completion all resources associated with the call - Upon call release completion all resources associated with the call
shall become available for access for new requests. shall become available for access for new requests.
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established by the control plane both gracefully and forcibly on established by the control plane both gracefully and forcibly on
demand. demand.
- Partially deleted calls or connections shall not remain within the - Partially deleted calls or connections shall not remain within the
network. network.
- End-to-end acknowledgments shall be used for connection deletion - End-to-end acknowledgments shall be used for connection deletion
requests. requests.
- Connection deletion shall not result in either restoration or - Connection deletion shall not result in either restoration or
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protection being initiated. protection being initiated.
- The control plane shall support management plane and neighboring - The control plane shall support management plane and neighboring
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device requests for status query. device requests for status query.
- The UNI shall support initial registration and updates of the UNI-C - The UNI shall support initial registration and updates of the UNI-C
with the network via the control plane. with the network via the control plane.
6.4. Optical Connection granularity 6.4. Optical Connection granularity
The service granularity is determined by the specific technology, The service granularity is determined by the specific technology,
framing and bit rate of the physical interface between the ONE and framing and bit rate of the physical interface between the ONE and
the client at the edge and by the capabilities of the ONE. The the client at the edge and by the capabilities of the ONE. The
control plane needs to support signaling and routing for all the control plane needs to support signaling and routing for all the
services supported by the ONE. In general, there should not be a one- services supported by the ONE. In general, there should not be a one-
to-one correspondence imposed between the granularity of the service to-one correspondence imposed between the granularity of the service
provided and the maximum capacity of the interface to the user. provided and the maximum capacity of the interface to the user.
The control plane shall support the ITU Rec. G.709 connection The control plane shall support the ITU Rec. G.709 connection
granularity for the OTN network. granularity for the OTN network.
The control plane shall support the SDH/SONET connection granularity. The control plane shall support the SDH/SONET connection granularity.
Sub-rate interfaces shall be supported by the optical control plane The optical control plane shall support sub-rate interfaces
such as VT /TU granularity (as low as 1.5 Mb/s). such as VT /TU granularity (as low as 1.5 Mb/s).
The following fiber channel interfaces shall be supported by the The following fiber channel interfaces shall be supported by the
control plane if the given interfaces are available on the equipment: control plane if the given interfaces are available on the equipment:
- FC-12 - FC-12
- FC-50 - FC-50
- FC-100 - FC-100
- FC-200 - FC-200
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We use "service level" to describe priority related characteristics We use "service level" to describe priority related characteristics
of connections, such as holding priority, set-up priority, or of connections, such as holding priority, set-up priority, or
restoration priority. The intent currently is to allow each carrier restoration priority. The intent currently is to allow each carrier
to define the actual service level in terms of priority, protection, to define the actual service level in terms of priority, protection,
and restoration options. Therefore, individual carriers will and restoration options. Therefore, individual carriers will
determine mapping of individual service levels to a specific set of determine mapping of individual service levels to a specific set of
quality features. quality features.
The control plane shall be capable of mapping individual service The control plane shall be capable of mapping individual service
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classes into specific priority or protection and restoration options. classes into specific priority or protection and restoration options.
6.5.2. Diverse Routing Attributes 6.5.2. Diverse Routing Attributes
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The diversity refers to the fact that a disjoint set of network resources (links Diversity refers to the fact that a disjoint set of network resources (links and
and nodes) is utilized to provision multiple parallel optical connections nodes) is utilized to provision multiple parallel optical connections terminated
terminated between a pair of ingress and egress ports. There are different between a pair of ingress and egress ports. There are different levels of
levels of diversity based on link, node or administrative policy as described diversity based on link, node or administrative policy as described below. In
below. In the simple node and link diversity case: the simple node and link diversity case:
. Two optical connections are said to be node-disjoint diverse, if the two . Two optical connections are said to be node-disjoint diverse, if the two
connections do not share any node along the path except the ingress and connections do not share any node along the path except the ingress and
egress nodes. egress nodes.
. Two optical connections are said to be link-disjoint diverse, if the two . Two optical connections are said to be link-disjoint diverse, if the two
connections do not share any link along the path. connections do not share any link along the path.
A more general concept of diversity is the Shared Risk Group (SRG) that is based A more general concept of diversity is the Shared Risk Group (SRG) that is based
risk sharing model and allows the definition of administrative policy-based on a risk-sharing model and allows the definition of administrative policy-based
diversity. A SRG is defined as a group of links or nodes that share a common diversity. A SRG is defined as a group of links or nodes that share a common
risk component, whose failure can potentially cause the failure of all the links risk component, whose failure can potentially cause the failure of all the links
or nodes in the group. When the SRG is applied to the link resource, it is or nodes in the group. When the SRG is applied to the link resource, it is
referred to as shared risk link group (SRLG). For example, all fiber links that referred to as shared risk link group (SRLG). For example, all fiber links that
go through a common conduit under the ground belong to the same SRLG group, go through a common conduit under the ground belong to the same SRLG group,
because the conduit is a shared risk component whose failure, such as a cut, may because the conduit is a shared risk component whose failure, such as a cut, may
cause all fibers in the conduit to break. Note that SRLG is a relation defined cause all fibers in the conduit to break. Note that SRLG is a relation defined
within a group of links based upon a specific risk factor that can be defined within a group of links based upon a specific risk factor that can be defined
based on various technical or administrative grounds such as ˘sharing a based on various technical or administrative grounds such as Šsharing a
conduit÷, ˘within 10 miles of distance proximity÷ etc. Please see ITU-T G.7715 conduitĂ, Šwithin 10 miles of distance proximityĂ etc. Please see ITU-T G.7715
for more discussion [itu-rtg]. for more discussion [itu-rtg].
Therefore, two optical connections are said to be SRG-disjoint diverse if the Therefore, two optical connections are said to be SRG-disjoint diverse if the
two connections do not have any links or nodes that belong to the same SRG along two connections do not have any links or nodes that belong to the same SRG along
the path. the path.
The ability to route service paths diversely is a required control The ability to route service paths diversely is a required control
feature. Diverse routing is one of the connection parameters and is feature. Diverse routing is one of the connection parameters and is
specified at the time of the connection creation. specified at the time of the connection creation.
The control plane routing algorithms shall be able to route a single The control plane routing algorithms shall be able to route an optical
demand diversely from N previously routed demands in terms of link connection diversely from a previously routed connection in terms of link
disjoint path, node disjoint path and SRLG disjoint path. disjoint path, node disjoint path and SRG disjoint path.
7. Optical Service Provider Requirements 7. Optical Service Provider Requirements
This section discusses specific service control and management This section discusses specific service control and management
requirements from the service provider's point of view. requirements from the service provider's point of view.
7.1. Service Access Methods to Optical Networks 7.1. Service Access Methods to Optical Networks
In order to have access to the optical network service, a customer needs to be In order to have access to the optical network service, a customer needs to be
physically connected to the service provider network on the transport plane. The physically connected to the service provider network on the transport plane. The
control plane connection may or may not be required depending upon the service control plane connection may or may not be required depending upon the service
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invocation model provided to the customer: provisioned vs. signaled. For the invocation model provided to the customer: provisioned vs. signaled. For the
signaled, either direct or indirect signaling methods can be used depending upon signaled, either direct or indirect signaling methods can be used depending upon
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if the UNI proxy is utilized on the client side. The detailed discussion on the if the UNI proxy is utilized on the client side. The detailed discussion on the
UNI signaling methods is in [oif-uni]. UNI signaling methods is in [oif-uni].
Multiple access methods blow shall be supported: Multiple access methods blow shall be supported:
- Cross-office access (CNE co-located with ONE) - Cross-office access (CNE co-located with ONE)
- Direct remote access (Dedicated links to the user) - Direct remote access (Dedicated links to the user)
- Remote access via access sub-network (via a - Remote access via access sub-network (via a
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When control domains exists for routing and signaling purpose, there will be When control domains exists for routing and signaling purpose, there will be
intra-domain routing/signaling and inter-domain routing/signaling. In general, intra-domain routing/signaling and inter-domain routing/signaling. In general,
domain-based routing/signaling autonomy is desired and the intra-domain domain-based routing/signaling autonomy is desired and the intra-domain
routing/signaling and the inter-domain routing/signaling should be agnostic to routing/signaling and the inter-domain routing/signaling should be agnostic to
each other. each other.
Routing and signaling for multi-level hierarchies shall be supported Routing and signaling for multi-level hierarchies shall be supported
to allow carriers to configure their networks as needed. to allow carriers to configure their networks as needed.
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7.3.2. Network Interconnections 7.3.2. Network Interconnections
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Subnetworks may have multiple points of inter-connections. All Sub-networks may have multiple points of inter-connections. All
relevant NNI functions, such as routing, reachability information relevant NNI functions, such as routing, reachability information
exchanges, and inter-connection topology discovery must recognize and exchanges, and inter-connection topology discovery must recognize and
support multiple points of inter-connections between subnetworks. support multiple points of inter-connections between subnetworks.
Dual inter-connection is often used as a survivable architecture. Dual inter-connection is often used as a survivable architecture.
The control plane shall provide support for routing and signaling for The control plane shall provide support for routing and signaling for
subnetworks having multiple points of interconnection. subnetworks having multiple points of interconnection.
7.4. Names and Address Management 7.4. Names and Address Management
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directory service is essential for the implementation of overlay model. directory service is essential for the implementation of overlay model.
7.4.3. Network element Identification 7.4.3. Network element Identification
Each control domain and each network element within a carrier network shall be Each control domain and each network element within a carrier network shall be
uniquely identifiable. Similarly all the service access points shall be uniquely uniquely identifiable. Similarly all the service access points shall be uniquely
identifiable. identifiable.
7.5. Policy-Based Service Management Framework 7.5. Policy-Based Service Management Framework
The IPO service must be supported by a robust policy-based management The optical service must be supported by a robust policy-based management
system to be able to make important decisions. system to be able to make important decisions.
Examples of policy decisions include: Examples of policy decisions include:
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- What types of connections can be set up for a given UNI? - What types of connections can be set up for a given UNI?
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- What information can be shared and what information must be - What information can be shared and what information must be
restricted in automatic discovery functions? restricted in automatic discovery functions?
- What are the security policies over signaling interfaces? - What are the security policies over signaling interfaces?
- What routing policies should be applied in the path selection? E.g - What routing policies should be applied in the path selection? E.g
The definition of the link diversity. The definition of the link diversity.
Requirements: Requirements:
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to successfully deliver automated provisioning for optical services: to successfully deliver automated provisioning for optical services:
- Network resource discovery - Network resource discovery
- Address assignment and resolution - Address assignment and resolution
- Routing information propagation and dissemination - Routing information propagation and dissemination
- Path calculation and selection - Path calculation and selection
- Connection management - Connection management
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These capabilities may be supported by a combination of functions These capabilities may be supported by a combination of functions
across the control and the management planes. across the control and the management planes.
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8.1.2. Control Plane Functions for Network Control
The following are essential functions needed to support network The following are essential functions needed to support network
control capabilities: control capabilities:
- Signaling - Signaling
- Routing - Routing
- Automatic resource, service and neighbor discovery - Automatic resource, service and neighbor discovery
Specific requirements for signaling, routing and discovery are Specific requirements for signaling, routing and discovery are
addressed in Section 9. addressed in Section 9.
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protection and restoration schemes. protection and restoration schemes.
- Control plane failures shall not affect active connections and - Control plane failures shall not affect active connections and
shall not adversely impact the transport and data planes. shall not adversely impact the transport and data planes.
- The control plane should support separation of control function - The control plane should support separation of control function
entities including routing, signaling and discovery and should allow entities including routing, signaling and discovery and should allow
different control distributions of those functionalities, including different control distributions of those functionalities, including
centralized, distributed or hybrid. centralized, distributed or hybrid.
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- The control plane should support physical separation of the control - The control plane should support physical separation of the control
plane from the transport plane to support either tightly coupled or plane from the transport plane to support either tightly coupled or
loosely coupled control plane solutions. loosely coupled control plane solutions.
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- The control plane should support the routing and signaling proxy to - The control plane should support the routing and signaling proxy to
participate in the normal routing and signaling message exchange and participate in the normal routing and signaling message exchange and
processing. processing.
- Security and resilience are crucial issues for the control plane - Security and resilience are crucial issues for the control plane
and will be addressed in Section 10 and 11 of this document. and will be addressed in Section 10 and 11 of this document.
8.2. Signaling Communication Network (SCN) 8.2. Signaling Communication Network (SCN)
The signaling communication network is a transport network for The signaling communication network is a transport network for
control plane messages and it consists of a set of control channels control plane messages and it consists of a set of control channels
that interconnect the nodes within the control plane. Therefore, the that interconnects the nodes within the control plane. Therefore, the
signaling communication network must be accessible by each of the signaling communication network must be accessible by each of the
communicating nodes (e.g., OXCs). If an out-of-band IP-based control communicating nodes (e.g., OXCs). If an out-of-band IP-based control
message transport network is an overlay network built on top of the message transport network is an overlay network built on top of the
IP data network using some tunneling technologies, these tunnels must IP data network using some tunneling technologies, these tunnels must
be standards-based such as IPSec, GRE, etc. be standards-based such as IPSec, GRE, etc.
- The signaling communication network must terminate at each of the - The signaling communication network must terminate at each of the
nodes in the transport plane. nodes in the transport plane.
- The signaling communication network shall not be assumed to have - The signaling communication network shall not be assumed to have
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link or channel. For example, using the overhead bytes in SONET data link or channel. For example, using the overhead bytes in SONET data
framing as a logical communication channel falls into the in-band framing as a logical communication channel falls into the in-band
signaling methods. signaling methods.
- In fiber, Out-of-band signaling: The signaling messages are carried - In fiber, Out-of-band signaling: The signaling messages are carried
over a dedicated communication channel separate from the optical over a dedicated communication channel separate from the optical
data-bearing channels, but within the same fiber. For example, a data-bearing channels, but within the same fiber. For example, a
dedicated wavelength or TDM channel may be used within the same fiber dedicated wavelength or TDM channel may be used within the same fiber
as the data channels. as the data channels.
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- Out-of-fiber signaling: The signaling messages are carried over a - Out-of-fiber signaling: The signaling messages are carried over a
dedicated communication channel or path within different fibers to dedicated communication channel or path within different fibers to
those used by the optical data-bearing channels. For example, those used by the optical data-bearing channels. For example,
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dedicated optical fiber links or communication path via separate and dedicated optical fiber links or communication path via separate and
independent IP-based network infrastructure are both classified as independent IP-based network infrastructure are both classified as
out-of-fiber signaling. out-of-fiber signaling.
The UNI control channel and proxy signaling defined in the OIF UNI The UNI control channel and proxy signaling defined in the OIF UNI
1.0 [oif-uni] shall be supported. 1.0 [oif-uni] shall be supported.
The signaling communication network provides communication The signaling communication network provides communication
mechanisms between entities in the control plane. mechanisms between entities in the control plane.
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8.3 Control Plane Interface to Data Plane 8.3 Control Plane Interface to Data Plane
In the situation where the control plane and data plane are decoupled, this In the situation where the control plane and data plane are decoupled, this
interface needs to be standardized. interface needs to be standardized.
Requirements for a standard control-data plane interface are under Requirements for a standard control-data plane interface are under
study. The specification of a control plane interface to the data study. The specification of a control plane interface to the data
plane is outside the scope of this document. plane is outside the scope of this document.
Control plane should support a standards based interface to configure Control plane should support a standards based interface to configure
and switching fabrics and port functions. switching fabrics and port functions via the management plane.
Data plane shall monitor and detect the failure (LOL, LOS, etc.) and Data plane shall monitor and detect the failure (LOL, LOS, etc.) and
quality degradation (high BER, etc.) of the signals and be able to quality degradation (high BER, etc.) of the signals and be able to
provide signal-failure and signal-degrade alarms to the control plane provide signal-failure and signal-degrade alarms to the control plane
accordingly to trigger proper mitigation actions in the control accordingly to trigger proper mitigation actions in the control
plane. plane.
8.4. Management Plane Interface to Data Plane 8.4. Management Plane Interface to Data Plane
The management plane shall be responsible for the network resource The management plane shall be responsible for the network resource
management in the data plane. It should able to partition the network management in the data plane. It should able to partition the network
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resources and control the allocation and the deallocation of the resources and control the allocation and the deallocation of the
resource for the use by the control plane. resource for the use by the control plane.
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Data plane shall monitor and detect the failure and quality Data plane shall monitor and detect the failure and quality
degradation of the signals and be able to provide signal-failure and degradation of the signals and be able to provide signal-failure and
signal-degrade alarms plus associated detailed fault information to signal-degrade alarms plus associated detailed fault information to
the management plane to trigger and enable the management for fault the management plane to trigger and enable the management for fault
location and repair. location and repair.
Management plane failures shall not affect the normal operation of a Management plane failures shall not affect the normal operation of a
configured and operational control plane or data plane. configured and operational control plane or data plane.
8.5. Control Plane Interface to Management Plane 8.5. Control Plane Interface to Management Plane
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The control, management and transport plane each has its well-defined network The control, management and transport plane each has its well-defined network
functions. Those functions are orthogonal to each other. However, this does not functions. Those functions are orthogonal to each other. However, this does not
total independency. Since the management plane is responsible for the management total independency. Since the management plane is responsible for the management
of both control plane and transport plane, the management plane plays an of both control plane and transport plane, the management plane plays an
authoritative role authoritative role
In general, the management plane shall have authority over the In general, the management plane shall have authority over the
control plane. Management plane should be able to configure the control plane. Management plane should be able to configure the
routing, signaling and discovery control parameters such as hold-down routing, signaling and discovery control parameters such as hold-down
timers, hello-interval, etc. to effect the behavior of the control timers, hello-interval, etc. to affect the behavior of the control
plane. plane.
In the case of network failure, both the management plane and In the case of network failure, both the management plane and
the control plane need fault information at the same priority. The the control plane need fault information at the same priority. The
control plane shall be responsible for providing necessary statistic control plane shall be responsible for providing necessary statistic
data such as call counts, traffic counts to the management plane. data such as call counts, traffic counts to the management plane.
They should be available upon the query from the management plane. They should be available upon the query from the management plane.
The management plane shall be able to tear down connections The management plane shall be able to tear down connections
established by the control plane both gracefully and forcibly on established by the control plane both gracefully and forcibly on
demand. demand.
8.6. IP and Optical Control Plane Interconnection 8.6. IP and Optical Control Plane Interconnection
The control plane interconnection model defines the way how two The control plane interconnection model defines how two
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control networks can be interconnected in terms of controlling control networks can be interconnected in terms of controlling
relationship and control information flow allowed between them. relationship and control information flow allowed between them.
There are three basic types of control plane network interconnection There are three basic types of control plane network interconnection
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models: overlay, peer and hybrid, which are defined in the IETF IPO models: overlay, peer and hybrid, which are defined in the IETF IPO
WG document [ipo_frame]. See Appendix A for more discussion. WG document [ipo_frame]. See Appendix A for more discussion.
Choosing the level of coupling depends upon a number of different Choosing the level of coupling depends upon a number of different
factors, some of which are: factors, some of which are:
- Variety of clients using the optical network - Variety of clients using the optical network
- Relationship between the client and optical network - Relationship between the client and optical network
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directory service is not available. directory service is not available.
9.2. Signaling Functions 9.2. Signaling Functions
Call and connection control and management signaling messages are Call and connection control and management signaling messages are
used for the establishment, modification, status query and release of used for the establishment, modification, status query and release of
an end-to-end optical connection. Unless otherwise specified, the an end-to-end optical connection. Unless otherwise specified, the
word "signaling" refers to both inter-domain and intra-domain word "signaling" refers to both inter-domain and intra-domain
signaling. signaling.
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- The inter-domain signaling protocol shall be agnostic to the intra- - The inter-domain signaling protocol shall be agnostic to the intra-
domain signaling protocol for all the domains within the network. domain signaling protocol for all the domains within the network.
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- Signaling shall support both strict and loose routing. - Signaling shall support both strict and loose routing.
- Signaling shall support individual as well as groups of connection - Signaling shall support individual as well as groups of connection
requests. requests.
- Signaling shall support fault notifications. - Signaling shall support fault notifications.
- Inter-domain signaling shall support per connection, globally - Inter-domain signaling shall support per connection, globally
unique identifiers for all connection management primitives based on unique identifiers for all connection management primitives based on
a well-defined naming scheme. a well-defined naming scheme.
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- Per domain reachability summarization - Per domain reachability summarization
Major concerns for routing protocol performance are scalability and Major concerns for routing protocol performance are scalability and
stability, which impose the following requirement on the routing stability, which impose the following requirement on the routing
protocols: protocols:
- The routing protocol shall scale with the size of the network - The routing protocol shall scale with the size of the network
The routing protocols shall support following requirements: The routing protocols shall support following requirements:
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- Routing protocol shall support hierarchical routing information - Routing protocol shall support hierarchical routing information
dissemination, including topology information aggregation and dissemination, including topology information aggregation and
summarization. summarization.
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- The routing protocol(s) shall minimize global information and keep - The routing protocol(s) shall minimize global information and keep
information locally significant as much as possible. information locally significant as much as possible.
Over external interfaces only reachability information, next Over external interfaces only reachability information, next
routing hop and service capability information should be exchanged. routing hop and service capability information should be exchanged.
Any other network related information shall not leak out to other Any other network related information shall not leak out to other
networks. networks.
- The routing protocol shall be able to minimize global information - The routing protocol shall be able to minimize global information
and keep information locally significant as much as possible (e.g., and keep information locally significant as much as possible (e.g.,
information local to a node, a sub-network, a domain, etc). For information local to a node, a sub-network, a domain, etc). For
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consideration to be made by network operators. consideration to be made by network operators.
9.4. Requirements for path selection 9.4. Requirements for path selection
The following are functional requirements for path selection: The following are functional requirements for path selection:
- Path selection shall support shortest path routing. - Path selection shall support shortest path routing.
- Path selection shall also support constraint-based routing. At - Path selection shall also support constraint-based routing. At
least the following constraints shall be supported: least the following constraints shall be supported:
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- Cost - Cost
- Link utilization - Link utilization
- Diversity - Diversity
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- Service Class - Service Class
- Path selection shall be able to include/exclude some specific - Path selection shall be able to include/exclude some specific
network resources, based on policy. network resources, based on policy.
- Path selection shall be able to support different levels of - Path selection shall be able to support different levels of
diversity, including node, link, SRLG and SRG. diversity, including node, link, SRLG and SRG.
- Path selection algorithms shall provide carriers the ability to - Path selection algorithms shall provide carriers the ability to
support a wide range of services and multiple levels of service support a wide range of services and multiple levels of service
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- Control adjacency that detect and verify the logical neighboring - Control adjacency that detect and verify the logical neighboring
relation between two control entities associated with data plane relation between two control entities associated with data plane
network elements that form either physical or logical adjacency. network elements that form either physical or logical adjacency.
The control plane shall support manual neighbor adjacency The control plane shall support manual neighbor adjacency
configuration to either overwrite or supplement the automatic configuration to either overwrite or supplement the automatic
neighbor discovery function. neighbor discovery function.
9.5.2. Resource Discovery 9.5.2. Resource Discovery
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Resource discovery is concerned with the ability to verify physical Resource discovery is concerned with the ability to verify physical
connectivity between two ports on adjacent network elements, improve connectivity between two ports on adjacent network elements, improve
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inventory management of network resources, detect configuration inventory management of network resources, detect configuration
mismatches between adjacent ports, associating port characteristics mismatches between adjacent ports, associating port characteristics
of adjacent network elements, etc. Resource discovery shall be of adjacent network elements, etc. Resource discovery shall be
supported. supported.
Resource discovery can be achieved through either manual provisioning Resource discovery can be achieved through either manual provisioning
or automated procedures. The procedures are generic while the or automated procedures. The procedures are generic while the
specific mechanisms and control information can be technology specific mechanisms and control information can be technology
dependent. dependent.
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10. Requirements for service and control plane resiliency 10. Requirements for service and control plane resiliency
Resiliency is a network capability to continue its operations under Resiliency is a network capability to continue its operations under
the condition of failures within the network. The automatic switched the condition of failures within the network. The automatic switched
optical network assumes the separation of control plane and data optical network assumes the separation of control plane and data
plane. Therefore the failures in the network can be divided into plane. Therefore the failures in the network can be divided into
those affecting the data plane and those affecting the control plane. those affecting the data plane and those affecting the control plane.
To provide enhanced optical services, resiliency measures in both To provide enhanced optical services, resiliency measures in both
data plane and control plane should be implemented. The following data plane and control plane should be implemented. The following
failure handling principles shall be supported. Failure-handling principles shall be supported.
The control plane shall provide optical service failure detection and The control plane shall provide optical service failure detection and
recovery functions such that the failures in the data plane within recovery functions such that the failures in the data plane within
the control plane coverage can be quickly mitigated. the control plane coverage can be quickly mitigated.
The failure of control plane shall not in any way adversely affect The failure of control plane shall not in any way adversely affect
the normal functioning of existing optical connections in the data the normal functioning of existing optical connections in the data
plane. plane.
In general, there shall be no single point of failure for all major In general, there shall be no single point of failure for all major
control plane functions, including signaling, routing etc. The control plane functions, including signaling, routing etc. The
control plane shall provide reliable transfer of signaling messages control plane shall provide reliable transfer of signaling messages
and flow control mechanisms for easing any congestion within the and flow control mechanisms for easing any congestion within the
control plane. control plane.
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10.1. Service resiliency 10.1. Service resiliency
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In circuit-switched transport networks, the quality and reliability In circuit-switched transport networks, the quality and reliability
of the established optical connections in the transport plane can be of the established optical connections in the transport plane can be
enhanced by the protection and restoration mechanisms provided by the enhanced by the protection and restoration mechanisms provided by the
control plane functions. Rapid recovery is required by transport control plane functions. Rapid recovery is required by transport
network providers to protect service and also to support stringent network providers to protect service and also to support stringent
Service Level Agreements (SLAs) that dictate high reliability and Service Level Agreements (SLAs) that dictate high reliability and
availability for customer connectivity. availability for customer connectivity.
Protection and restoration are closely related techniques for Protection and restoration are closely related techniques for
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signal degradation to the control plane in the form of the signal signal degradation to the control plane in the form of the signal
failure alarm and signal degrade alarm. failure alarm and signal degrade alarm.
The control plane shall support both alarm-triggered and hold-down The control plane shall support both alarm-triggered and hold-down
timers based protection switching and dynamic restoration for failure timers based protection switching and dynamic restoration for failure
recovery. recovery.
Clients will have different requirements for connection availability. Clients will have different requirements for connection availability.
These requirements can be expressed in terms of the "service level", These requirements can be expressed in terms of the "service level",
which can be mapped to different restoration and protection options which can be mapped to different restoration and protection options
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and priority related connection characteristics, such as holding and priority related connection characteristics, such as holding
priority(e.g. pre-emptable or not), set-up priority, or restoration priority(e.g. pre-emptable or not), set-up priority, or restoration
priority. However, how the mapping of individual service levels to a priority. However, how the mapping of individual service levels to a
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specific set of protection/restoration options and connection specific set of protection/restoration options and connection
priorities will be determined by individual carriers. priorities will be determined by individual carriers.
In order for the network to support multiple grades of service, the In order for the network to support multiple grades of service, the
control plane must support differing protection and restoration control plane must support differing protection and restoration
options on a per connection basis. options on a per connection basis.
In order for the network to support multiple grades of service, the In order for the network to support multiple grades of service, the
control plane must support setup priority, restoration priority and control plane must support setup priority, restoration priority and
holding priority on a per connection basis. holding priority on a per connection basis.
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Protection and restoration configuration should be based on software Protection and restoration configuration should be based on software
only. only.
The control plane shall allow the modification of protection and The control plane shall allow the modification of protection and
restoration attributes on a per-connection basis. restoration attributes on a per-connection basis.
The control plane shall support mechanisms for reserving bandwidth The control plane shall support mechanisms for reserving bandwidth
resources for restoration. resources for restoration.
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The control plane shall support mechanisms for normalizing connection The control plane shall support mechanisms for normalizing connection
routing (reversion) after failure repair. routing (reversion) after failure repair.
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Normal connection management operations (e.g., connection deletion) Normal connection management operations (e.g., connection deletion)
shall not result in protection/restoration being initiated. shall not result in protection/restoration being initiated.
10.2. Control plane resiliency 10.2. Control plane resiliency
The control plane may be affected by failures in signaling network The control plane may be affected by failures in signaling network
connectivity and by software failures (e.g., signaling, topology and connectivity and by software failures (e.g., signaling, topology and
resource discovery modules). resource discovery modules).
The signaling control plane should implement signaling message The signaling control plane should implement signaling message
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11. Security Considerations 11. Security Considerations
In this section, security considerations and requirements for optical In this section, security considerations and requirements for optical
services and associated control plane requirements are described. services and associated control plane requirements are described.
11.1. Optical Network Security Concerns 11.1. Optical Network Security Concerns
Since optical service is directly related to the physical network Since optical service is directly related to the physical network
which is fundamental to a telecommunications infrastructure, which is fundamental to a telecommunications infrastructure,
stringent security assurance mechanism should be implemented in stringent security assurance mechanism should be implemented in
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optical networks. optical networks.
In terms of security, an optical connection consists of two aspects. In terms of security, an optical connection consists of two aspects.
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One is security of the data plane where an optical connection itself One is security of the data plane where an optical connection itself
belongs, and the other is security of the control plane. belongs, and the other is security of the control plane.
11.1.1. Data Plane Security 11.1.1. Data Plane Security
- Misconnection shall be avoided in order to keep the user's data - Misconnection shall be avoided in order to keep the user's data
confidential. For enhancing integrity and confidentiality of data, confidential. For enhancing integrity and confidentiality of data,
it may be helpful to support scrambling of data at layer 2 or it may be helpful to support scrambling of data at layer 2 or
encryption of data at a higher layer. encryption of data at a higher layer.
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control plane. control plane.
- Discovery information, including neighbor discovery, service - Discovery information, including neighbor discovery, service
discovery, resource discovery and reachability information should be discovery, resource discovery and reachability information should be
exchanged in a secure way. exchanged in a secure way.
- Information on security-relevant events occurring in the control - Information on security-relevant events occurring in the control
plane or security-relevant operations performed or attempted in the plane or security-relevant operations performed or attempted in the
control plane shall be logged in the management plane. control plane shall be logged in the management plane.
Y. Xue et al
- The management plane shall be able to analyze and exploit logged - The management plane shall be able to analyze and exploit logged
data in order to check if they violate or threat security of the data in order to check if they violate or threat security of the
Y. Xue et al
control plane. control plane.
- The control plane shall be able to generate alarm notifications - The control plane shall be able to generate alarm notifications
about security related events to the management plane in an about security related events to the management plane in an
adjustable and selectable fashion. adjustable and selectable fashion.
- The control plane shall support recovery from successful and - The control plane shall support recovery from successful and
attempted intrusion attacks. attempted intrusion attacks.
11.2. Service Access Control 11.2. Service Access Control
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signaling messages. This is important in order to prevent Denial of signaling messages. This is important in order to prevent Denial of
Service attacks. The UNI and E-NNI should also include mechanisms, Service attacks. The UNI and E-NNI should also include mechanisms,
such as usage-based billing based on CAC, to ensure non-repudiation such as usage-based billing based on CAC, to ensure non-repudiation
of connection management messages. of connection management messages.
- Each entity should be authorized to use network resources according - Each entity should be authorized to use network resources according
to the administrative policy set by the operator. to the administrative policy set by the operator.
12. Acknowledgements 12. Acknowledgements
The authors of this document would like to extend our special appreciation to The authors of this document would like to extend our special appreciation to John
John Strand for his initial contributions to the carrier requirements. We Strand for his initial contributions to the carrier requirements. We also want to
also want to acknowledge the valuable inputs from, Yangguang Xu, Zhiwei Lin, acknowledge the valuable inputs from, Yangguang Xu, Zhiwei Lin,
Eve Verma, Daniel Awduche, James Luciani, Deborah Brunhard and Lynn Neir, Eve Verma, Daniel Awduche, James Luciani, Deborah Brunhard and Lynn Neir,
Wesam Alanqar, Tammy Ferris, Mark Jones. Wesam Alanqar, Tammy Ferris, Mark Jones.
13. References 13. References
[rfc2026] S. Bradner, "The Internet Standards Process -- Revision 3," BCP 9, RFC [rfc2026] S. Bradner, "The Internet Standards Process -- Revision 3," BCP 9, RFC
2026, IETF October 1996. 2026, IETF October 1996.
[rfc2119] S. Bradner, ˘Key words for use in RFC to indicate requirement levels÷,
BCP 14, RFC 2119, 1997
Y. Xue et al Y. Xue et al
[rfc2119] S. Bradner, ˘Ke y words for use in RFC to indicate requirement
levels÷, BCP 14, RFC 2119, 1997
[itu-otn] ITU-T G.872 (2000) ű Architecture of Optical Transport Networks. [itu-otn] ITU-T G.872 (2000) ű Architecture of Optical Transport Networks.
[itu-g709] ITU-T G.709 (2001)ű Network Node Interface for the Optical Transport [itu-g709] ITU-T G.709 (2001)ű Network Node Interface for the Optical Transport
Network. Network.
[itu-sdh] ITU-T Rec. G.803 (2000), Architecture of Transport Networks based on [itu-sdh] ITU-T Rec. G.803 (2000), Architecture of Transport Networks based on
the Synchronous Digital Hierarchy the Synchronous Digital Hierarchy
[ipo-frw] B. Rajagopalan, et. al ˘IP over Optical Networks: A Framework÷, work [ipo-frw] B. Rajagopalan, et. al ˘IP over Optical Networks: A Framework÷, work
in progress, IETF 2002 in progress, IETF 2002
skipping to change at page 40, line 5 skipping to change at page 39, line 52
[itu-astn] ITU-T Rec. G.8070/Y.1301 (2001), Requirements for the Automatic [itu-astn] ITU-T Rec. G.8070/Y.1301 (2001), Requirements for the Automatic
Switched Transport Network (ASTN). Switched Transport Network (ASTN).
[itu-ason] ITU-T Rec. G.8080/Y.1304 (2001), Architecture of the Automatic [itu-ason] ITU-T Rec. G.8080/Y.1304 (2001), Architecture of the Automatic
Switched Optical Network (ASON). Switched Optical Network (ASON).
[itu-dcm] ITU-T Rec. G.7713/Y.1704 (2001), Distributed Call and Connection [itu-dcm] ITU-T Rec. G.7713/Y.1704 (2001), Distributed Call and Connection
Management (DCM). Management (DCM).
Y. Xue et al
[itu-rtg] ITU-T Draft Rec. G.7715/Y.1706 (2002), Architecture and Requirements [itu-rtg] ITU-T Draft Rec. G.7715/Y.1706 (2002), Architecture and Requirements
for Routing in the Automatic Switched Optical Networks. for Routing in the Automatic Switched Optical Networks.
Y. Xue et al
[itu-lm] ITU-T Draft Rec. G.7716/Y.1706 (2002), Link Resource Management for [itu-lm] ITU-T Draft Rec. G.7716/Y.1706 (2002), Link Resource Management for
ASON Networks. (work in progress) ASON Networks. (work in progress)
[itu-disc] ITU-T Rec. G.7714/Y.1705 (2001), Generalized Automatic Discovery [itu-disc] ITU-T Rec. G.7714/Y.1705 (2001), Generalized Automatic Discovery
Techniques. Techniques.
[itu-dcn]ITU-T Rec. G.7712/Y.1703 (2001), Architecture and Specification of Data [itu-dcn]ITU-T Rec. G.7712/Y.1703 (2001), Architecture and Specification of Data
Communication Network. Communication Network.
[ansi-sonet] ANSI T1.105-2001, Synchronous Optical Network (SONET) - Basic
Description including Multiplex Structure, Rates and Formats
14 Author's Addresses 14 Author's Addresses
Yong Xue Yong Xue
UUNET/WorldCom UUNET/WorldCom
22001 Loudoun County Parkway 22001 Loudoun County Parkway
Ashburn, VA 20147 Ashburn, VA 20147
Email: yxue@ieee.org Email: yxue@ieee.org
Monica Lazer Monica Lazer
AT&T AT&T
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