draft-ietf-pce-stateful-sync-optimizations-04.txt   draft-ietf-pce-stateful-sync-optimizations-05.txt 
PCE Working Group E. Crabbe PCE Working Group E. Crabbe
Internet-Draft Internet-Draft
Intended status: Standards Track I. Minei Intended status: Standards Track I. Minei
Expires: May 4, 2016 Google, Inc. Expires: October 29, 2016 Google, Inc.
J. Medved J. Medved
Cisco Systems, Inc. Cisco Systems, Inc.
R. Varga R. Varga
Pantheon Technologies SRO Pantheon Technologies SRO
X. Zhang X. Zhang
D. Dhody D. Dhody
Huawei Technologies Huawei Technologies
November 1, 2015 April 27, 2016
Optimizations of Label Switched Path State Synchronization Procedures Optimizations of Label Switched Path State Synchronization Procedures
for a Stateful PCE for a Stateful PCE
draft-ietf-pce-stateful-sync-optimizations-04 draft-ietf-pce-stateful-sync-optimizations-05
Abstract Abstract
A stateful Path Computation Element (PCE) has access to not only the A stateful Path Computation Element (PCE) has access to not only the
information disseminated by the network's Interior Gateway Protocol information disseminated by the network's Interior Gateway Protocol
(IGP), but also the set of active paths and their reserved resources (IGP), but also the set of active paths and their reserved resources
for its computation. The additional Label Switched Path (LSP) state for its computation. The additional Label Switched Path (LSP) state
information allows the PCE to compute constrained paths while information allows the PCE to compute constrained paths while
considering individual LSPs and their interactions. This requires a considering individual LSPs and their interactions. This requires a
reliable state synchronization mechanism between the PCE and the reliable state synchronization mechanism between the PCE and the
skipping to change at page 1, line 42 skipping to change at page 1, line 42
motivations for optimizations to the base state synchronization motivations for optimizations to the base state synchronization
procedure and specifies the required Path Computation Element procedure and specifies the required Path Computation Element
Communication Protocol (PCEP) extensions. Communication Protocol (PCEP) extensions.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
Status of this Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
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 obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference 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."
This Internet-Draft will expire on May 4, 2016. This Internet-Draft will expire on October 29, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. State Synchronization Avoidance . . . . . . . . . . . . . . . 5 3. State Synchronization Avoidance . . . . . . . . . . . . . . . 4
3.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. State Synchronization Avoidance Procedure . . . . . . . . 5 3.2. State Synchronization Avoidance Procedure . . . . . . . . 4
3.3. PCEP Extensions . . . . . . . . . . . . . . . . . . . . . 9 3.3. PCEP Extensions . . . . . . . . . . . . . . . . . . . . . 9
3.3.1. LSP State Database Version Number TLV . . . . . . . . 9 3.3.1. LSP State Database Version Number TLV . . . . . . . . 9
3.3.2. Speaker Entity Identifier TLV . . . . . . . . . . . . 10 3.3.2. Speaker Entity Identifier TLV . . . . . . . . . . . . 10
4. Incremental State Synchronization . . . . . . . . . . . . . . 11 4. Incremental State Synchronization . . . . . . . . . . . . . . 11
4.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 12 4.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 12
4.2. Incremental Synchronization Procedure . . . . . . . . . . 13 4.2. Incremental Synchronization Procedure . . . . . . . . . . 13
5. PCE-triggered Initial Synchronization . . . . . . . . . . . . 15 5. PCE-triggered Initial Synchronization . . . . . . . . . . . . 15
5.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 15 5.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 15
5.2. PCE-triggered Initial State Synchronization Procedure . . 15 5.2. PCE-triggered Initial State Synchronization Procedure . . 15
6. PCE-triggered Re-synchronization . . . . . . . . . . . . . . . 16 6. PCE-triggered Re-synchronization . . . . . . . . . . . . . . 16
6.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 16 6.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 16
6.2. PCE-triggered State Re-synchronization Procedure . . . . . 16 6.2. PCE-triggered State Re-synchronization Procedure . . . . 16
7. Advertising Support of Synchronization Optimizations . . . . . 17 7. Advertising Support of Synchronization Optimizations . . . . 17
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
8.1. PCEP-Error Object . . . . . . . . . . . . . . . . . . . . 18 8.1. PCEP-Error Object . . . . . . . . . . . . . . . . . . . . 18
8.2. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . . 19 8.2. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 19
8.3. STATEFUL-PCE-CAPABILITY TLV . . . . . . . . . . . . . . . 19 8.3. STATEFUL-PCE-CAPABILITY TLV . . . . . . . . . . . . . . . 19
9. Manageability Considerations . . . . . . . . . . . . . . . . . 20 9. Manageability Considerations . . . . . . . . . . . . . . . . 20
9.1. Control of Function and Policy . . . . . . . . . . . . . . 20 9.1. Control of Function and Policy . . . . . . . . . . . . . 20
9.2. Information and Data Models . . . . . . . . . . . . . . . 20 9.2. Information and Data Models . . . . . . . . . . . . . . . 20
9.3. Liveness Detection and Monitoring . . . . . . . . . . . . 20 9.3. Liveness Detection and Monitoring . . . . . . . . . . . . 20
9.4. Verify Correct Operations . . . . . . . . . . . . . . . . 20 9.4. Verify Correct Operations . . . . . . . . . . . . . . . . 20
9.5. Requirements On Other Protocols . . . . . . . . . . . . . 20 9.5. Requirements On Other Protocols . . . . . . . . . . . . . 20
9.6. Impact On Network Operations . . . . . . . . . . . . . . . 21 9.6. Impact On Network Operations . . . . . . . . . . . . . . 21
10. Security Considerations . . . . . . . . . . . . . . . . . . . 21 10. Security Considerations . . . . . . . . . . . . . . . . . . . 21
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 21 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21
12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 21 12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 21
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
13.1. Normative References . . . . . . . . . . . . . . . . . . . 21 13.1. Normative References . . . . . . . . . . . . . . . . . . 21
13.2. Informative References . . . . . . . . . . . . . . . . . . 22 13.2. Informative References . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction 1. Introduction
The Path Computation Element Communication Protocol (PCEP) provides The Path Computation Element Communication Protocol (PCEP) provides
mechanisms for Path Computation Elements (PCEs) to perform path mechanisms for Path Computation Elements (PCEs) to perform path
computations in response to Path Computation Clients (PCCs) requests. computations in response to Path Computation Clients (PCCs) requests.
[I-D.ietf-pce-stateful-pce] describes a set of extensions to PCEP to [I-D.ietf-pce-stateful-pce] describes a set of extensions to PCEP to
provide stateful control. A stateful PCE has access to not only the provide stateful control. A stateful PCE has access to not only the
information carried by the network's Interior Gateway Protocol (IGP), information carried by the network's Interior Gateway Protocol (IGP),
skipping to change at page 13, line 5 skipping to change at page 13, line 7
synchronization of all LSPs. It is especially true when only a low synchronization of all LSPs. It is especially true when only a low
bandwidth communication channel is available (e.g., in-band control bandwidth communication channel is available (e.g., in-band control
channel for optical transport networks) and there is a substantial channel for optical transport networks) and there is a substantial
number of LSPs in the network. Another disadvantage of full LSP number of LSPs in the network. Another disadvantage of full LSP
synchronization is that it is a waste of communication bandwidth to synchronization is that it is a waste of communication bandwidth to
perform full LSP synchronization given the fact that the number of perform full LSP synchronization given the fact that the number of
LSP changes can be small during the time when PCEP session is down. LSP changes can be small during the time when PCEP session is down.
An incremental (Delta) LSP Database (LSP-DB) state synchronization is An incremental (Delta) LSP Database (LSP-DB) state synchronization is
described in this section, where only the LSPs underwent state change described in this section, where only the LSPs underwent state change
are synchronized between the session restart. This may include new/ are synchronized between the session restart. This may include
modified/deleted LSPs. new/modified/deleted LSPs.
4.2. Incremental Synchronization Procedure 4.2. Incremental Synchronization Procedure
[I-D.ietf-pce-stateful-pce] describes state synchronization and [I-D.ietf-pce-stateful-pce] describes state synchronization and
Section 3 describes state synchronization avoidance by using LSP-DB- Section 3 describes state synchronization avoidance by using LSP-DB-
VERSION TLV in its OPEN object. This section extends this idea to VERSION TLV in its OPEN object. This section extends this idea to
only synchronize the delta (changes) in case of version mismatch. only synchronize the delta (changes) in case of version mismatch.
If both PCEP speakers include the LSP-DB-VERSION TLV in the OPEN If both PCEP speakers include the LSP-DB-VERSION TLV in the OPEN
object and the LSP-DB-VERSION TLV values match, the PCC MAY skip object and the LSP-DB-VERSION TLV values match, the PCC MAY skip
skipping to change at page 16, line 7 skipping to change at page 16, line 6
the STATEFUL-PCE-CAPABILITY TLV (see Section 7). the STATEFUL-PCE-CAPABILITY TLV (see Section 7).
In order to allow a stateful PCE to control the LSP-DB In order to allow a stateful PCE to control the LSP-DB
synchronization after establishing a PCEP session, both PCEP speakers synchronization after establishing a PCEP session, both PCEP speakers
MUST set F bit to 1 in the OPEN message. If the TRIGGERED-INITIAL- MUST set F bit to 1 in the OPEN message. If the TRIGGERED-INITIAL-
SYNC capability is not advertised by a PCE and the PCC receives a SYNC capability is not advertised by a PCE and the PCC receives a
PCUpd with the SYNC flag set to 1, it MUST send a PCErr with the SRP- PCUpd with the SYNC flag set to 1, it MUST send a PCErr with the SRP-
ID-number of the PCUpd, Error-Type 20 and Error-Value TBD (suggested ID-number of the PCUpd, Error-Type 20 and Error-Value TBD (suggested
value - 4) 'Attempt to trigger synchronization when the TRIGGERED- value - 4) 'Attempt to trigger synchronization when the TRIGGERED-
SYNC capability has not been advertised' (see Section 8.1). If the SYNC capability has not been advertised' (see Section 8.1). If the
LSP-DB Version is mis-matched, it can send a PCUpd message with LSP-DB Version is mis-matched, it can send a PCUpd message with PLSP-
PLSP-ID = 0 and SYNC = 1 in order to trigger the LSP-DB ID = 0 and SYNC = 1 in order to trigger the LSP-DB synchronization
synchronization process. In this way, the PCE can control the process. In this way, the PCE can control the sequence of LSP
sequence of LSP synchronization among all the PCCs that are re- synchronization among all the PCCs that are re-establishing PCEP
establishing PCEP sessions with it. When the capability of PCE sessions with it. When the capability of PCE control is enabled,
control is enabled, only after a PCC receives this message, it will only after a PCC receives this message, it will start sending
start sending information to the PCE. The PCC SHOULD NOT send PCRpt information to the PCE. The PCC SHOULD NOT send PCRpt messages to
messages to the stateful PCE before it triggers the State the stateful PCE before it triggers the State Synchronization. This
Synchronization. This PCE-triggering capability can be applied to PCE-triggering capability can be applied to both full and incremental
both full and incremental state synchronization. If applied to the state synchronization. If applied to the later, the PCCs only send
later, the PCCs only send information that PCE does not possess, information that PCE does not possess, which is inferred from the
which is inferred from the LSP-DB version information exchanged in LSP-DB version information exchanged in the OPEN message (see
the OPEN message (see Section 4.2 for detailed procedure). Section 4.2 for detailed procedure).
Once the initial state synchronization is triggered by the PCE, the Once the initial state synchronization is triggered by the PCE, the
procedures and error checks remain unchanged from the full state procedures and error checks remain unchanged from the full state
synchronization ([I-D.ietf-pce-stateful-pce]). synchronization ([I-D.ietf-pce-stateful-pce]).
6. PCE-triggered Re-synchronization 6. PCE-triggered Re-synchronization
6.1. Motivation 6.1. Motivation
The accuracy of the computations performed by the PCE is tied to the The accuracy of the computations performed by the PCE is tied to the
skipping to change at page 18, line 15 skipping to change at page 18, line 14
The value comprises a single field - Flags (32 bits): The value comprises a single field - Flags (32 bits):
U (LSP-UPDATE-CAPABILITY - 1 bit): defined in U (LSP-UPDATE-CAPABILITY - 1 bit): defined in
[I-D.ietf-pce-stateful-pce]. [I-D.ietf-pce-stateful-pce].
S (INCLUDE-DB-VERSION - 1 bit): if set to 1 by both PCEP Speakers, S (INCLUDE-DB-VERSION - 1 bit): if set to 1 by both PCEP Speakers,
the PCC will include the LSP-DB-VERSION TLV in each LSP Object. the PCC will include the LSP-DB-VERSION TLV in each LSP Object.
See Section 3.2 for details. See Section 3.2 for details.
I (LSP-INSTANTIATION-CAPABILITY - 1 bit): defined in I (LSP-INSTANTIATION-CAPABILITY - 1 bit): defined in [I-D.ietf-pce-p
[I-D.ietf-pce-pce-initiated-lsp]. ce-initiated-lsp].
T (TRIGGERED-RESYNC - 1 bit): if set to 1 by both PCEP Speakers, the T (TRIGGERED-RESYNC - 1 bit): if set to 1 by both PCEP Speakers, the
PCE can trigger re-synchronization of LSPs at any point in the PCE can trigger re-synchronization of LSPs at any point in the
life of the session. See Section 6.2 for details. life of the session. See Section 6.2 for details.
D (DELTA-LSP-SYNC-CAPABILITY - 1 bit): if set to 1 by a PCEP D (DELTA-LSP-SYNC-CAPABILITY - 1 bit): if set to 1 by a PCEP
speaker, it indicates that the PCEP speaker allows incremental speaker, it indicates that the PCEP speaker allows incremental
(delta) state synchronization. See Section 4.2 for details. (delta) state synchronization. See Section 4.2 for details.
F (TRIGGERED-INITIAL-SYNC - 1 bit): if set to 1 by both PCEP F (TRIGGERED-INITIAL-SYNC - 1 bit): if set to 1 by both PCEP
skipping to change at page 19, line 40 skipping to change at page 19, line 40
synchronization. synchronization.
Error-Value=TBD(suggested This document Error-Value=TBD(suggested This document
value 7): Received an invalid value 7): Received an invalid
LSP DB Version Number LSP DB Version Number
8.2. PCEP TLV Type Indicators 8.2. PCEP TLV Type Indicators
IANA is requested to make the following allocation in the "PCEP TLV IANA is requested to make the following allocation in the "PCEP TLV
Type Indicators" registry. Type Indicators" registry.
Value Meaning Reference Value Meaning Reference
TBD(suggested value 23) LSP-DB-VERSION This document TBD(suggested value 23) LSP-DB-VERSION This document
TBD(suggested value 24) SPEAKER-ENTITY-ID This document TBD(suggested value 24) SPEAKER-ENTITY-ID This document
8.3. STATEFUL-PCE-CAPABILITY TLV 8.3. STATEFUL-PCE-CAPABILITY TLV
The STATEFUL-PCE-CAPABILITY TLV is defined in The STATEFUL-PCE-CAPABILITY TLV is defined in
[I-D.ietf-pce-stateful-pce] and a registry is requested to be created [I-D.ietf-pce-stateful-pce] and a registry is requested to be
to manage the flags in the TLV. IANA is requested to make the created to manage the flags in the TLV. IANA is requested to make
following allocation in the aforementioned registry. the following allocation in the aforementioned registry.
Bit Description Reference Bit Description Reference
TBD(suggested value 26) TRIGGERED-INITIAL-SYNC This document TBD(suggested value 26) TRIGGERED-INITIAL-SYNC This document
TBD(suggested value 27) DELTA-LSP-SYNC-CAPABILITY This document TBD(suggested value 27) DELTA-LSP-SYNC-CAPABILITY This document
TBD(suggested value 28) TRIGGERED-RESYNC This document TBD(suggested value 28) TRIGGERED-RESYNC This document
TBD(suggested value 30) INCLUDE-DB-VERSION This document TBD(suggested value 30) INCLUDE-DB-VERSION This document
9. Manageability Considerations 9. Manageability Considerations
All manageability requirements and considerations listed in [RFC5440] All manageability requirements and considerations listed in [RFC5440]
and [I-D.ietf-pce-stateful-pce] apply to PCEP protocol extensions and [I-D.ietf-pce-stateful-pce] apply to PCEP protocol extensions
defined in this document. In addition, requirements and defined in this document. In addition, requirements and
considerations listed in this section apply. considerations listed in this section apply.
9.1. Control of Function and Policy 9.1. Control of Function and Policy
skipping to change at page 21, line 34 skipping to change at page 21, line 34
We would like to thank Young Lee, Jonathan Hardwick, Sergio Belotti We would like to thank Young Lee, Jonathan Hardwick, Sergio Belotti
and Cyril Margaria for their comments and discussions. and Cyril Margaria for their comments and discussions.
12. Contributors 12. Contributors
Gang Xie Gang Xie
Huawei Technologies Huawei Technologies
F3-5-B R&D Center, Huawei Industrial Base, Bantian, Longgang District F3-5-B R&D Center, Huawei Industrial Base, Bantian, Longgang District
Shenzhen, Guangdong, 518129 Shenzhen, Guangdong, 518129
P.R. China P.R. China
Email: xiegang09@huawei.com Email: xiegang09@huawei.com
13. References 13. References
13.1. Normative References 13.1. Normative References
[I-D.ietf-pce-stateful-pce] [I-D.ietf-pce-stateful-pce]
Crabbe, E., Minei, I., Medved, J., and R. Varga, "PCEP Crabbe, E., Minei, I., Medved, J., and R. Varga, "PCEP
Extensions for Stateful PCE", Extensions for Stateful PCE", draft-ietf-pce-stateful-
draft-ietf-pce-stateful-pce-12 (work in progress), pce-14 (work in progress), March 2016.
October 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ Requirement Levels", BCP 14, RFC 2119,
RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440, Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009, DOI 10.17487/RFC5440, March 2009,
<http://www.rfc-editor.org/info/rfc5440>. <http://www.rfc-editor.org/info/rfc5440>.
13.2. Informative References 13.2. Informative References
[I-D.ietf-pce-pce-initiated-lsp] [I-D.ietf-pce-pce-initiated-lsp]
skipping to change at page 23, line 23 skipping to change at page 23, line 15
Huawei Technologies Huawei Technologies
F3-5-B R&D Center, Huawei Industrial Base, Bantian, Longgang District F3-5-B R&D Center, Huawei Industrial Base, Bantian, Longgang District
Shenzhen, Guangdong 518129 Shenzhen, Guangdong 518129
P.R.China P.R.China
Email: zhang.xian@huawei.com Email: zhang.xian@huawei.com
Dhruv Dhody Dhruv Dhody
Huawei Technologies Huawei Technologies
Divyashree Techno Park, Whitefield Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560037 Bangalore, Karnataka 560066
India India
Email: dhruv.ietf@gmail.com Email: dhruv.ietf@gmail.com
 End of changes. 17 change blocks. 
77 lines changed or deleted 76 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/