draft-ietf-ospf-lls-interface-id-03.txt   draft-ietf-ospf-lls-interface-id-04.txt 
Open Shortest Path First IGP P. Psenak, Ed. Open Shortest Path First IGP P. Psenak, Ed.
Internet-Draft K. Talaulikar Internet-Draft K. Talaulikar
Intended status: Standards Track Cisco Systems, Inc. Intended status: Standards Track Cisco Systems, Inc.
Expires: December 21, 2018 W. Henderickx Expires: January 2, 2019 W. Henderickx
Nokia Nokia
P. Pillay-Esnault P. Pillay-Esnault
Huawei Huawei
June 19, 2018 July 1, 2018
OSPF LLS Extensions for Local Interface ID Advertisement OSPF LLS Extensions for Local Interface ID Advertisement
draft-ietf-ospf-lls-interface-id-03 draft-ietf-ospf-lls-interface-id-04
Abstract Abstract
This draft describes the extensions to OSPF link-local signaling to Every OSPF interface is assigned an identifier, Interface ID, which
uniquely identifies the interface on the router. In some cases it is
useful to know the Interface ID assigned by the adjacent router on
its side of the adjacency (Remote Interface ID).
This draft describes the extensions to OSPF link-local signalling to
advertise the Local Interface Identifier. advertise the Local Interface Identifier.
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", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in RFC 2119 [RFC2119]. "OPTIONAL" in this document are to be interpreted as described in
[BCP14] [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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 https://datatracker.ietf.org/drafts/current/. Drafts is at https://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 December 21, 2018. This Internet-Draft will expire on January 2, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 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
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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 . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Interface ID Exchange using TE Opaque LSA . . . . . . . . . . 2 2. Interface ID Exchange using TE Opaque LSA . . . . . . . . . . 3
3. Interface ID Exchange using OSPF LLS . . . . . . . . . . . . 3 3. Interface ID Exchange using OSPF LLS . . . . . . . . . . . . 3
3.1. Local Interface Identifier TLV . . . . . . . . . . . . . 3 3.1. Local Interface Identifier TLV . . . . . . . . . . . . . 3
4. Backward Compatibility with RFC 4203 . . . . . . . . . . . . 4 4. Backward Compatibility with RFC 4203 . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 4 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
9. Normative References . . . . . . . . . . . . . . . . . . . . 5 9. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
Every interface is assigned an Interface ID, which uniquely Every OSPF interface is assigned an Interface ID, which uniquely
identifies the interface on the router. For example, some identifies the interface on the router. For example, some
implementations MAY be able to use the MIB-II IfIndex [RFC2863] as implementations MAY be able to use the MIB-II IfIndex [RFC2863] as
the Interface ID. the Interface ID.
Local/Remote Interface Identifiers MAY be flooded by OSPF [RFC2328] Local/Remote Interface Identifiers MAY be flooded by OSPF [RFC2328]
as defined in [RFC4203]. From the perspective of the advertising as defined in [RFC4203]. From the perspective of the advertising
router, the Local Interface Identifier is a known value, however the router, the Local Interface Identifier is a known value, however the
Remote Interface Identifier needs to be learnt before it can be Remote Interface Identifier needs to be learnt before it can be
advertised. [RFC4203] suggests to use TE Link Local LSA [RFC3630] to advertised. [RFC4203] suggests to use TE Link Local LSA [RFC3630] to
communicate the Local Interface Identifier to neighbors on the link. communicate the Local Interface Identifier to neighbors on the link.
Though such mechanism works, it has some drawbacks. Though such mechanism works, it has some drawbacks.
This draft proposes an extension to OSPF link-local signaling (LLS) This draft proposes an extension to OSPF link-local signalling
[RFC5613] to advertise the Local Interface Identifier. [RFC5613] to advertise the Local Interface Identifier.
2. Interface ID Exchange using TE Opaque LSA 2. Interface ID Exchange using TE Opaque LSA
Usage of the Link Local TE Opaque LSA to propagate the Local Usage of the Link Local TE Opaque LSA to propagate the Local
Interface Identifier to the neighbors on the link is described in Interface Identifier to the neighbors on the link is described in
[RFC4203]. This mechanism has following problems: [RFC4203]. This mechanism has following problems:
LSAs can only be flooded over an existing adjacency that is in LSAs can only be flooded over an existing adjacency that is in
Exchange state or greater. The adjacency state machine progresses Exchange state or greater. The adjacency state machine progresses
skipping to change at page 3, line 17 skipping to change at page 3, line 26
without the Remote Interface Identifier. Later, when the TE Link without the Remote Interface Identifier. Later, when the TE Link
Opaque LSA arrives, the link must be advertised again, this time Opaque LSA arrives, the link must be advertised again, this time
with the valid Remote Interface Identifier. Implementations may with the valid Remote Interface Identifier. Implementations may
choose to wait before advertising the link, but there is no choose to wait before advertising the link, but there is no
guarantee that the neighbor will ever advertise the TE Link Opaque guarantee that the neighbor will ever advertise the TE Link Opaque
LSA with the Interface Identifier. In summary, the existing LSA with the Interface Identifier. In summary, the existing
mechanism does not guarantee that the Remote Interface Identifier mechanism does not guarantee that the Remote Interface Identifier
is known at the time the link is advertised. is known at the time the link is advertised.
The TE Opaque LSA is defined for MPLS Traffic Engineering, but the The TE Opaque LSA is defined for MPLS Traffic Engineering, but the
knowledge of the Remote Interface Identifier is useful for other knowledge of the Remote Interface Identifier is useful also for
cases where MPLS TE is not used. One example is the lack of a cases where MPLS TE is not used. One example is the lack of a
valid 2-way connectivity check for parallel point-to-point links valid 2-way connectivity check for parallel point-to-point links
between OSPF routers. In such cases, TE Opaque LSAs are not between OSPF routers.
exchanged solely for 2-way connectivity validation.
3. Interface ID Exchange using OSPF LLS 3. Interface ID Exchange using OSPF LLS
To address the problems described earlier and to allow the Interface To address the problems described earlier and to allow the Interface
Identifier exchange to be part of the neighbor discovery process, we Identifier exchange to be part of the neighbor discovery process, we
propose to extend OSPF link-local signaling to advertise the Local propose to extend OSPF link-local signalling to advertise the Local
Interface Identifier in OSPF Hello packets. Interface Identifier in OSPF Hello packets.
3.1. Local Interface Identifier TLV 3.1. Local Interface Identifier TLV
The Local Interface Identifier TLV is a LLS TLV. It has following The Local Interface Identifier TLV is a LLS TLV. It has following
format: 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Interface Identifier | | Local Interface Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where: where:
Type: TBD, suggested value 18 Type: 18
Length: 4 octet Length: 4 octets
Local Interface Identifier: The value of the local Interface Local Interface Identifier: The value of the local Interface
Identifier. Identifier.
Local Interface Identifier TLV signalling using LLS is applicable to Local Interface Identifier TLV signalling using LLS is applicable to
all OSPF interface types other than virtual links. all OSPF interface types other than virtual links.
4. Backward Compatibility with RFC 4203 4. Backward Compatibility with RFC 4203
Implementations which support Local Interface ID signalling using LLS Implementations which support Local Interface ID signalling using LLS
skipping to change at page 4, line 30 skipping to change at page 4, line 37
During the rare conditions, when the Local Interface ID changes, a During the rare conditions, when the Local Interface ID changes, a
timing interval may exist, where the received values of the Local timing interval may exist, where the received values of the Local
Interface ID advertised through LLS and Link Local TE Opaque LSA may Interface ID advertised through LLS and Link Local TE Opaque LSA may
differ. Such situation is temporary and received values via both differ. Such situation is temporary and received values via both
mechanisms should become equal as soon as the next Hello and/or Link mechanisms should become equal as soon as the next Hello and/or Link
Local TE Opaque LSA is re-generated by the originator. Local TE Opaque LSA is re-generated by the originator.
5. IANA Considerations 5. IANA Considerations
This specification updates Link Local Signalling TLV Identifiers This specification allocates a single code point from the "Open
registry. Shortest Path First (OSPF) Link Local Signalling (LLS) - Type/Length/
Value Identifiers (TLV)" registry.
Following values is allocated: Following values is allocated:
o 18 - Local Interface Identifier TLV o 18 - Local Interface Identifier TLV
6. Security Considerations 6. Security Considerations
Implementations must assure that malformed LLS TLVs and Sub-TLVs Implementations must assure that malformed LLS TLVs and Sub-TLVs
permutations do not result in errors which cause hard OSPF failures. permutations do not result in errors which cause hard OSPF failures.
7. Contributors 7. Contributors
8. Acknowledgements 8. Acknowledgements
Thanks to Tony Przygienda for his extensive review and useful Thanks to Tony Przygienda for his extensive review and useful
comments. comments.
9. Normative References 9. Normative References
[BCP14] , <https://tools.ietf.org/html/bcp14>.
[ISO10589]
International Organization for Standardization,
"Intermediate system to Intermediate system intra-domain
routeing information exchange protocol for use in
conjunction with the protocol for providing the
connectionless-mode Network Service (ISO 8473)", ISO/
IEC 10589:2002, Second Edition, Nov 2002.
[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, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998, DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>. <https://www.rfc-editor.org/info/rfc2328>.
[RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group
skipping to change at page 5, line 35 skipping to change at page 6, line 5
[RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in
Support of Generalized Multi-Protocol Label Switching Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005,
<https://www.rfc-editor.org/info/rfc4203>. <https://www.rfc-editor.org/info/rfc4203>.
[RFC5613] Zinin, A., Roy, A., Nguyen, L., Friedman, B., and D. [RFC5613] Zinin, A., Roy, A., Nguyen, L., Friedman, B., and D.
Yeung, "OSPF Link-Local Signaling", RFC 5613, Yeung, "OSPF Link-Local Signaling", RFC 5613,
DOI 10.17487/RFC5613, August 2009, DOI 10.17487/RFC5613, August 2009,
<https://www.rfc-editor.org/info/rfc5613>. <https://www.rfc-editor.org/info/rfc5613>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
Authors' Addresses Authors' Addresses
Peter Psenak (editor) Peter Psenak (editor)
Cisco Systems, Inc. Cisco Systems, Inc.
Apollo Business Center Apollo Business Center
Mlynske nivy 43 Mlynske nivy 43
Bratislava 821 09 Bratislava 821 09
Slovakia Slovakia
Email: ppsenak@cisco.com Email: ppsenak@cisco.com
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