draft-ietf-lsr-ospf-l2bundles-00.txt   draft-ietf-lsr-ospf-l2bundles-01.txt 
Link State Routing K. Talaulikar Link State Routing K. Talaulikar
Internet-Draft P. Psenak Internet-Draft P. Psenak
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: May 2, 2021 October 29, 2020 Expires: October 29, 2021 April 27, 2021
Advertising L2 Bundle Member Link Attributes in OSPF Advertising L2 Bundle Member Link Attributes in OSPF
draft-ietf-lsr-ospf-l2bundles-00 draft-ietf-lsr-ospf-l2bundles-01
Abstract Abstract
There are deployments where the Layer 3 interface on which OSPF There are deployments where the Layer 3 interface on which OSPF
operates is a Layer 2 interface bundle. Existing OSPF advertisements operates is a Layer 2 interface bundle. Existing OSPF advertisements
only support advertising link attributes of the Layer 3 interface. only support advertising link attributes of the Layer 3 interface.
If entities external to OSPF wish to control traffic flows on the If entities external to OSPF wish to control traffic flows on the
individual physical links which comprise the Layer 2 interface bundle individual physical links which comprise the Layer 2 interface bundle
link attribute information about the bundle members is required. link attribute information about the bundle members is required.
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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-
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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 2, 2021. This Internet-Draft will expire on October 29, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2021 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
(https://trustee.ietf.org/license-info) in effect on the date of (https://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
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5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.1. Normative References . . . . . . . . . . . . . . . . . . 7 6.1. Normative References . . . . . . . . . . . . . . . . . . 7
6.2. Informational References . . . . . . . . . . . . . . . . 8 6.2. Informational References . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
There are deployments where the Layer 3 interface on which an OSPF There are deployments where the Layer 3 interface on which an OSPF
adjacency is established is a Layer 2 interface bundle, for instance adjacency is established is a Layer 2 interface bundle, for instance
a Link Aggregation Group (LAG) [IEEE802.1AX] . This reduces the a Link Aggregation Group (LAG) [IEEE802.1AX]. This reduces the
number of adjacencies which need to be maintained by the routing number of adjacencies that need to be maintained by the routing
protocol in cases where there are parallel links between the protocol in cases where there are parallel links between the
neighbors. Entities external to OSPF such as Path Computation neighbors. Entities external to OSPF such as Path Computation
Elements (PCE) [RFC4655] may wish to control traffic flows on Elements (PCE) [RFC4655] may wish to control traffic flows on
individual members of the underlying Layer 2 bundle. In order to do individual members of the underlying Layer 2 bundle. To do so, link
so link attribute information about individual bundle members is attribute information about individual bundle members is required.
required. The protocol extensions defined in this document provide The protocol extensions defined in this document provide the means to
the means to advertise this information. advertise this information.
This document introduces new sub-TLVs to advertise link attribute This document introduces new sub-TLVs to advertise link attribute
information for each of the L2 Bundle members which comprise the information for each of the L2 Bundle members which comprise the
Layer 3 interface on which OSPF operates. Similar capabilities were Layer 3 interface on which OSPF operates. Similar capabilities were
introduced in IS-IS via [RFC8668]. introduced in IS-IS via [RFC8668].
[RFC8665] and [RFC8666] introduced the adjacency segment identifier [RFC8665] and [RFC8666] introduced the adjacency segment identifier
(Adj-SID) link attribute for OSPFv2 and OSPFv3 respectively which can (Adj-SID) link attribute for OSPFv2 and OSPFv3 respectively which can
be used as an instruction to forwarding to send traffic over a be used as an instruction to forwarding to send traffic over a
specific link [RFC8402]. This document enables the advertisement of specific link [RFC8402]. This document enables the advertisement of
the Adj-SIDs using the same Adjacency SID sub-TLV at the granularity the Adj-SIDs using the same Adjacency SID sub-TLV at the granularity
level of each L2 Bundle member link so that traffic may be steered level of each L2 Bundle member link so that traffic may be steered
over that specific member link. over that specific member link.
Note that the new advertisements at the L2 Bundle member link level Note that the new advertisements at the L2 Bundle member link level
in this document are intended to be provided to external (to OSPF) in this document are intended to be provided to external (to OSPF)
entities and does not alter or change OSPF route computation process. entities and does not alter or change the OSPF route computation
process. The following items are intentionally not defined and/or
The following items are intentionally not defined and/or are outside are outside the scope of this document:
the scope of this document:
o What link attributes will be advertised. This is determined by o What link attributes will be advertised. This is determined by
the needs of the external entities. the needs of the external entities.
o A minimum or default set of link attributes. o A minimum or default set of link attributes.
o How these attributes are configured o How these attributes are configured
o How the advertisements are used o How the advertisements are used
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
2. L2 Bundle Member Attributes 2. L2 Bundle Member Attributes
A new L2 Bundle Member Attributes sub-TLV is introduced to advertise A new L2 Bundle Member Attributes sub-TLV is introduced to advertise
L2 Bundle member attributes in both OSPFv2 and OSPFv3. In case of L2 Bundle member attributes in both OSPFv2 and OSPFv3. In the case
OSPFv2, this sub-TLV is an optional sub-TLV of the OSPFv2 Extended of OSPFv2, this sub-TLV is an optional sub-TLV of the OSPFv2 Extended
Link TLV that is used to describe link attributes via the OSPFv2 Link TLV that is used to describe link attributes via the OSPFv2
Extended Link Opaque LSA [RFC7684]. In case of OSPFv3, this sub-TLV Extended Link Opaque LSA [RFC7684]. In case of OSPFv3, this sub-TLV
is an optional sub-TLV of the Router Link TLV of the OSPFv3 E-Router- is an optional sub-TLV of the Router Link TLV of the OSPFv3 E-Router-
LSA [RFC8362]. LSA [RFC8362].
When the OSPF adjacency is associated with L2 Bundle interface, this When the OSPF adjacency is associated with an L2 Bundle interface,
sub-TLV is used to advertise the underlying L2 Bundle member links this sub-TLV is used to advertise the underlying L2 Bundle member
along with their individual link attributes. Inclusion of this links along with their respective link attributes. Inclusion of this
information implies that the identified link is a member of the L2 information implies that the identified link is a member of the L2
bundle associated with OSPF L3 link and that the member link is bundle associated with an OSPF L3 link and that the member link is
operationally up. Therefore advertisements of member links MUST NOT operationally up. Therefore advertisements of member links MUST NOT
be done when the member link becomes operationally down or it is no be done when the member link becomes operationally down or it is no
longer a member of the identified L2 Bundle. longer a member of the identified L2 Bundle.
The L2 Bundle Member Attributes sub-TLV has the following format: The L2 Bundle Member Attributes sub-TLV has the following format:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| L2 Bundle Member Descriptor | | L2 Bundle Member Descriptor |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Member Link attribute sub-TLVs (variable) // | Member Link attribute sub-TLVs (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: L2 Bundle Member Attributes sub-TLV Format Figure 1: L2 Bundle Member Attributes sub-TLV Format
Where: Where:
Type: TBD1 for OSPFv2 and TBD2 for OSPFv3 Type: 24 for OSPFv2 and 29 for OSPFv3
Length: Variable. Length: Variable.
L2 Bundle Member Descriptor: A 4 octet Link Local Identifier as L2 Bundle Member Descriptor: A 4 octet Link Local Identifier as
described in [RFC4202] and used in [RFC8510] for the member link. described in [RFC4202] and used in [RFC8510] for the member link.
Link attributes for L2 Bundle Member Links are advertised as sub-TLVs Link attributes for L2 Bundle Member Links are advertised as sub-TLVs
of the L2 Bundle Member Attribute sub-TLV. of the L2 Bundle Member Attribute sub-TLV.
In the case of OSPFv2, the L2 Bundle Member Attributes sub-TLV shares In the case of OSPFv2, the L2 Bundle Member Attributes sub-TLV shares
the sub-TLV space of the Extended Link TLV and the sub-TLVs of the the sub-TLV space of the Extended Link TLV and the sub-TLVs of the
Extended Link TLV MAY be used to describe the attributes of the Extended Link TLV MAY be used to describe the attributes of the
member link. The Figure 2 below lists sub-TLVs and their member link. Figure 2 below lists sub-TLVs and their applicability
applicability for L2 Bundle member links. The sub-TLVs that are not for L2 Bundle member links. The sub-TLVs that are not applicable
applicable MUST NOT be used as sub-TLVs for the L2 Bundle Member MUST NOT be used as sub-TLVs for the L2 Bundle Member Attributes sub-
Attributes sub-TLV. Specifications that introduce new sub-TLVs of TLV. Specifications that introduce new sub-TLVs of the Extended Link
the Extended Link TLV MUST indicate their applicability for the L2 TLV MUST indicate their applicability for the L2 Bundle Member
Bundle Member Attributes sub-TLV. An implementation MUST ignore any Attributes sub-TLV. An implementation MUST ignore any sub-TLVs
sub-TLVs received that are not applicable in the context of the L2 received that are not applicable in the context of the L2 Bundle
Bundle Member Attribute sub-TLV. Member Attribute sub-TLV.
Y - applicable Y - applicable
N - not-applicable N - not-applicable
1 SID/Label (N) 1 SID/Label (N)
2 Adj-SID (Y) 2 Adj-SID (Y)
3 LAN Adj-SID/Label (Y) 3 LAN Adj-SID/Label (Y)
4 Network-to-Router Metric (N) 4 Network-to-Router Metric (N)
5 RTM Capability (N) 5 RTM Capability (N)
6 OSPFv2 Link MSD (N) 6 OSPFv2 Link MSD (N)
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13 Min/Max Unidirectional Link Delay (Y) 13 Min/Max Unidirectional Link Delay (Y)
14 Unidirectional Delay Variation (Y) 14 Unidirectional Delay Variation (Y)
15 Unidirectional Link Loss (Y) 15 Unidirectional Link Loss (Y)
16 Unidirectional Residual Bandwidth (Y) 16 Unidirectional Residual Bandwidth (Y)
17 Unidirectional Available Bandwidth (Y) 17 Unidirectional Available Bandwidth (Y)
18 Unidirectional Utilized Bandwidth (Y) 18 Unidirectional Utilized Bandwidth (Y)
19 Administrative Group (Y) 19 Administrative Group (Y)
20 Extended Administrative Group (Y) 20 Extended Administrative Group (Y)
21 Maximum Link Bandwidth (Y) 21 Maximum Link Bandwidth (Y)
22 Traffic Engineering Metric (Y) 22 Traffic Engineering Metric (Y)
TBD1 L2 Bundle Member Attributes (N) 24 L2 Bundle Member Attributes (N)
Figure 2: Applicability of OSPFv2 Link Attribute sub-TLVs for L2 Figure 2: Applicability of OSPFv2 Link Attribute sub-TLVs for L2
Bundle Members Bundle Members
In the case of OSPFv3, the L2 Bundle Member Attributes sub-TLV shares In the case of OSPFv3, the L2 Bundle Member Attributes sub-TLV shares
the sub-TLV space of the Router Link TLV and the sub-TLVs of the the sub-TLV space of the Router Link TLV and the sub-TLVs of the
Router Link TLV MAY be used to describe the attributes of the member Router Link TLV MAY be used to describe the attributes of the member
link. The Figure 3 below lists sub-TLVs that are applicable for link. Figure 3 below lists sub-TLVs that are applicable for Router
Router Link TLV and their applicability for L2 Bundle member links. Link TLV and their applicability for L2 Bundle member links. The
The sub-TLVs that are not applicable MUST NOT be used as sub-TLVs for sub-TLVs that are not applicable MUST NOT be used as sub-TLVs for the
the L2 Bundle Member Attributes sub-TLV. Specifications that L2 Bundle Member Attributes sub-TLV. Specifications that introduce
introduce new sub-TLVs of the Router Link TLV MUST indicate their new sub-TLVs of the Router Link TLV MUST indicate their applicability
applicability for the L2 Bundle Member Attributes sub-TLV. An for the L2 Bundle Member Attributes sub-TLV. An implementation MUST
implementation MUST ignore any sub-TLVs received that are not ignore any sub-TLVs received that are not applicable in the context
applicable in the context of the L2 Bundle Member Attribute sub-TLV. of the L2 Bundle Member Attribute sub-TLV.
Y - applicable Y - applicable
N - not-applicable N - not-applicable
5 Adj-SID (Y) 5 Adj-SID (Y)
6 LAN Adj-SID (Y) 6 LAN Adj-SID (Y)
7 SID/Label (N) 7 SID/Label (N)
8 Graceful-Link-Shutdown (N) 8 Graceful-Link-Shutdown (N)
9 OSPFv3 Link MSD (N) 9 OSPFv3 Link MSD (N)
10 Application Specific Link Attributes (Y) 10 Application Specific Link Attributes (Y)
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15 Unidirectional Link Loss (Y) 15 Unidirectional Link Loss (Y)
16 Unidirectional Residual Bandwidth (Y) 16 Unidirectional Residual Bandwidth (Y)
17 Unidirectional Available Bandwidth (Y) 17 Unidirectional Available Bandwidth (Y)
18 Unidirectional Utilized Bandwidth (Y) 18 Unidirectional Utilized Bandwidth (Y)
19 Administrative Group (Y) 19 Administrative Group (Y)
20 Extended Administrative Group (Y) 20 Extended Administrative Group (Y)
21 Traffic Engineering Metric (Y) 21 Traffic Engineering Metric (Y)
22 Maximum Link Bandwidth (Y) 22 Maximum Link Bandwidth (Y)
23 Local Interface IPv6 Address (N) 23 Local Interface IPv6 Address (N)
24 Remote Interface IPv6 Address (N) 24 Remote Interface IPv6 Address (N)
TBD2 L2 Bundle Member Attributes (N) 29 L2 Bundle Member Attributes (N)
Figure 3: Applicability of OSPFv3 Link Attribute sub-TLVs for L2 Figure 3: Applicability of OSPFv3 Link Attribute sub-TLVs for L2
Bundle Members Bundle Members
3. IANA Considerations 3. IANA Considerations
This document adds new sub-TLVs to the OSPFv2 and OSPFv3 registry. This document adds new sub-TLVs to the OSPFv2 and OSPFv3 registry.
The following sub-TLV is added to the OSPFv2 Extended Link TLV sub- The following code-point has been assigned via early allocation in
TLVs registry under the OSPFv2 Parameters IANA registry: the OSPFv2 Extended Link TLV sub-TLVs registry under the OSPFv2
Parameters IANA registry:
Value: TBD1 Value: 24
Name: L2 Bundle Member Attributes Name: L2 Bundle Member Attributes
The following sub-TLV is added to the OSPFv3 Extended LSA sub-TLVs The following code-point has been assigned via early allocation in
registry under the OSPFv3 Parameters IANA registry: the OSPFv3 Extended LSA sub-TLVs registry under the OSPFv3 Parameters
IANA registry:
Value: TBD2
Value: 29
Name: L2 Bundle Member Attributes Name: L2 Bundle Member Attributes
4. Security Considerations 4. Security Considerations
The OSPF protocol has supported the advertisement of link attribute The OSPF protocol has supported the advertisement of link attribute
information, including link identifiers, for many years. The information, including link identifiers, for many years. The
advertisements defined in this document are identical to existing advertisements defined in this document are identical to existing
advertisements defined in [RFC3630], [RFC4203], [RFC5329], [RFC7471], advertisements defined in [RFC3630], [RFC4203], [RFC5329], [RFC7471],
[RFC8665] and [RFC8666] - but are associated with L2 links which are [RFC8665] and [RFC8666] - but are associated with L2 links which are
part of a bundle interface on which the OSPF protocol operates. part of a bundle interface on which the OSPF protocol operates.
There are therefore no new security issues introduced by the There are therefore no new security issues introduced by the
extensions in this document. extensions in this document.
As always, if the protocol is used in an environment where As always, if the protocol is used in an environment where
unauthorized access to the physical links on which OSPF packets are unauthorized access to the physical links on which OSPF packets are
sent occurs then attacks are possible. The use of authentication as sent occurs then attacks are possible. The use of authentication as
defined in [RFC5709], [RFC7474], [RFC4552] and [RFC7166] is defined in [RFC5709], [RFC7474], [RFC4552] and [RFC7166] is
recommended to prevent such attacks. recommended for preventing such attacks.
5. Acknowledgements 5. Acknowledgements
This document leverages the similar work done for IS-IS and the This document leverages the similar work done for IS-IS and the
authors of this document would like to acknowledge the contributrions authors of this document would like to acknowledge the contributions
of the authors of [RFC8668]. of the authors of [RFC8668].
6. References 6. References
6.1. Normative References 6.1. Normative References
[IEEE802.1AX] [IEEE802.1AX]
Institute of Electrical and Electronics Engineers, "IEEE Institute of Electrical and Electronics Engineers, "IEEE
Standard for Local and Metropolitan Area Networks - Link Standard for Local and Metropolitan Area Networks - Link
Aggregation.", Nov 2008. Aggregation.", Nov 2008.
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