draft-ietf-ospf-lls-interface-id-02.txt   draft-ietf-ospf-lls-interface-id-03.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: November 16, 2018 W. Henderickx Expires: December 21, 2018 W. Henderickx
Nokia Nokia
P. Pillay-Esnault P. Pillay-Esnault
Huawei Huawei
May 15, 2018 June 19, 2018
OSPF LLS Extensions for Local Interface ID Advertisement OSPF LLS Extensions for Local Interface ID Advertisement
draft-ietf-ospf-lls-interface-id-02 draft-ietf-ospf-lls-interface-id-03
Abstract Abstract
This draft describes the extensions to OSPF link-local signaling to This draft describes the extensions to OSPF link-local signaling to
advertise 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", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [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
skipping to change at page 1, line 41 skipping to change at page 1, line 41
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 November 16, 2018. This Internet-Draft will expire on December 21, 2018.
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
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
skipping to change at page 2, line 23 skipping to change at page 2, line 23
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Interface ID Exchange using TE Opaque LSA . . . . . . . . . . 2 2. Interface ID Exchange using TE Opaque LSA . . . . . . . . . . 2
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 . . . . . . . . . . . . . . . . . . . . . . . . 4
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
9. Normative References . . . . . . . . . . . . . . . . . . . . 4 9. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction 1. Introduction
Every interface is assigned an Interface ID, which uniquely Every 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 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 signaling (LLS)
[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
independently on each side of the adjacency and, as such, may independently on each side of the adjacency and, as such, may
reach the Full state on one side before the TE Link Opaque LSA reach the Full state on one side before the TE Link Opaque LSA
arrives. The consequence is that link can be initially advertised arrives. The consequence is that link can be initially advertised
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. Implementation 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 Remote Interface Identifier is mechanism does not guarantee that the Remote Interface Identifier
known at the time the link is advertised. is known at the time the link is advertised.
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 for other
cases where MPLS TE is not used. One example is the lack of valid cases where MPLS TE is not used. One example is the lack of a
2-way connectivity check for remote parallel point-to-point links valid 2-way connectivity check for parallel point-to-point links
in OSPF. In such case, TE Opaque LSAs are not exchanged solely between OSPF routers. In such cases, TE Opaque LSAs are not
for 2-way connectivity correctness. 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
Identifiers 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 signaling 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 new LLS TLV. It has The Local Interface Identifier TLV is a LLS TLV. It has following
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: TBD, suggested value 18
Length: 4 octet Length: 4 octet
Local Interface Identifier: The value of the local Interface Local Interface Identifier: The value of the local Interface
Identifier. Identifier.
Local Interface Identifier TLV MUST be present in all Hello packets Local Interface Identifier TLV signalling using LLS is applicable to
on all link types, except packets that are sent to the remote end of all OSPF interface types other than virtual links.
the virtual-link.
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
MUST prefer the Local Interface ID value received through LLS over MUST prefer the Local Interface ID value received through LLS over
the value received through the Link Local TE Opaque LSAs. the value received through Link Local TE Opaque LSA if both are
received from the same OSPF router.
Implementations which also support the Local Interface ID signalling Implementations which support Local Interface ID signalling via Link
via Link Local TE Opaque LSA MAY continue to do so to ensure backward Local TE Opaque LSA MAY continue to do so to ensure backward
compatibility and they MUST signal the same local interface id via compatibility. If they also support Local Interface ID signalling
both mechanisms. using LLS as described herein, they SHOULD signal the same Local
Interface ID via both mechanisms.
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 updates Link Local Signalling TLV Identifiers
registry. 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 TLV and Sub-TLV 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
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[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, (TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC3630, September 2003, DOI 10.17487/RFC3630, September 2003,
<https://www.rfc-editor.org/info/rfc3630>. <https://www.rfc-editor.org/info/rfc3630>.
[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>.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>.
[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>.
Authors' Addresses Authors' Addresses
Peter Psenak (editor) Peter Psenak (editor)
Cisco Systems, Inc. Cisco Systems, Inc.
Apollo Business Center Apollo Business Center
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