< draft-ietf-ospf-ospfv3-lsa-extend-00.txt   draft-ietf-ospf-ospfv3-lsa-extend-01.txt >
Network Working Group A. Lindem Network Working Group A. Lindem
Internet-Draft Ericsson Internet-Draft Ericsson
Intended status: Standards Track S. Mirtorabi Intended status: Standards Track S. Mirtorabi
Expires: April 18, 2014 A. Roy Expires: August 14, 2014 A. Roy
F. Baker F. Baker
Cisco Systems Cisco Systems
October 15, 2013 February 10, 2014
OSPFv3 LSA Extendibility OSPFv3 LSA Extendibility
draft-ietf-ospf-ospfv3-lsa-extend-00.txt draft-ietf-ospf-ospfv3-lsa-extend-01.txt
Abstract Abstract
OSPFv3 requires functional extension beyond what can readily be done OSPFv3 requires functional extension beyond what can readily be done
with the fixed-format Link State Advertisement (LSA) as described in with the fixed-format Link State Advertisement (LSA) as described in
RFC 5340. Without LSA extension, attributes associated with OSPFv3 RFC 5340. Without LSA extension, attributes associated with OSPFv3
links and advertised IPv6 prefixes must be advertised in separate links and advertised IPv6 prefixes must be advertised in separate
LSAs and correlated to the fixed-format LSA. This document extends LSAs and correlated to the fixed-format LSA. This document extends
the LSA format by allowing the optional inclusion of Type-Length- the LSA format by allowing the optional inclusion of Type-Length-
Value (TLV) tuples in the LSAs. Backward compatibility mechanisms Value (TLV) tuples in the LSAs. Backward compatibility mechanisms
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on April 18, 2014. This Internet-Draft will expire on August 14, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
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4. OSPFv3 E-Router-LSA . . . . . . . . . . . . . . . . . . . . . 8 4. OSPFv3 E-Router-LSA . . . . . . . . . . . . . . . . . . . . . 8
5. OSPFv3 E-Network-LSA . . . . . . . . . . . . . . . . . . . . . 10 5. OSPFv3 E-Network-LSA . . . . . . . . . . . . . . . . . . . . . 10
6. OSPFv3 E-Inter-Area-Prefix-LSA . . . . . . . . . . . . . . . . 12 6. OSPFv3 E-Inter-Area-Prefix-LSA . . . . . . . . . . . . . . . . 12
7. OSPFv3 E-Inter-Area-Router-LSA . . . . . . . . . . . . . . . . 14 7. OSPFv3 E-Inter-Area-Router-LSA . . . . . . . . . . . . . . . . 14
8. OSPFv3 E-AS-External-LSA . . . . . . . . . . . . . . . . . . . 16 8. OSPFv3 E-AS-External-LSA . . . . . . . . . . . . . . . . . . . 16
9. OSPFv3 E-NSSA-LSA . . . . . . . . . . . . . . . . . . . . . . 19 9. OSPFv3 E-NSSA-LSA . . . . . . . . . . . . . . . . . . . . . . 19
10. OSPFv3 E-Link-LSA . . . . . . . . . . . . . . . . . . . . . . 20 10. OSPFv3 E-Link-LSA . . . . . . . . . . . . . . . . . . . . . . 20
11. OSPFv3 E-Intra-Area-Prefix-LSA . . . . . . . . . . . . . . . . 23 11. OSPFv3 E-Intra-Area-Prefix-LSA . . . . . . . . . . . . . . . . 23
12. LSA Extension Backward Compatibility . . . . . . . . . . . . . 24 12. LSA Extension Backward Compatibility . . . . . . . . . . . . . 24
12.1. Extended LSA Mixed-Mode Backward Compatibility . . . . . . 25 12.1. Extended LSA Mixed-Mode Backward Compatibility . . . . . . 25
12.2. LSA TLV Processing Backward Compatibility . . . . . . . . 25 12.1.1. Area Extended LSA Mixed-Mode Backward
13. Security Considerations . . . . . . . . . . . . . . . . . . . 26 Compatibility . . . . . . . . . . . . . . . . . . . . 25
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27 12.2. LSA TLV Processing Backward Compatibility . . . . . . . . 26
15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 28 13. Security Considerations . . . . . . . . . . . . . . . . . . . 27
15.1. Normative References . . . . . . . . . . . . . . . . . . . 28 14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
15.2. Informative References . . . . . . . . . . . . . . . . . . 28 15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Appendix A. Configurable Constants . . . . . . . . . . . . . . . 29 15.1. Normative References . . . . . . . . . . . . . . . . . . . 29
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 30 15.2. Informative References . . . . . . . . . . . . . . . . . . 29
Appendix A. Global Configuration Parameters . . . . . . . . . . . 30
Appendix B. Area Configuration Parameters . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 32
1. Introduction 1. Introduction
OSPFv3 requires functional extension beyond what can readily be done OSPFv3 requires functional extension beyond what can readily be done
with the fixed-format Link State Advertisement (LSA) as described in with the fixed-format Link State Advertisement (LSA) as described in
RFC 5340 [OSPFV3]. Without LSA extension, attributes associated with RFC 5340 [OSPFV3]. Without LSA extension, attributes associated with
OSPFv3 links and advertised IPv6 prefixes must be advertised in OSPFv3 links and advertised IPv6 prefixes must be advertised in
separate LSAs and correlated to the fixed-format LSA. This document separate LSAs and correlated to the fixed-format LSA. This document
extends the LSA format by allowing the optional inclusion of Type- extends the LSA format by allowing the optional inclusion of Type-
Length-Value (TLV) tuples in the LSAs. Backward compatibility Length-Value (TLV) tuples in the LSAs. Backward compatibility
skipping to change at page 24, line 21 skipping to change at page 24, line 21
LSAs is out of scope and must be covered in the documents describing LSAs is out of scope and must be covered in the documents describing
those extensions. Both full and, if applicable, partial deployment those extensions. Both full and, if applicable, partial deployment
should be covered for future OSPFv3 LSA extensions. should be covered for future OSPFv3 LSA extensions.
For simplicity and to avoid the scaling impact of maintaining both For simplicity and to avoid the scaling impact of maintaining both
TLV and non-TLV based versions of the same LSA within a routing TLV and non-TLV based versions of the same LSA within a routing
domain, the base backward compatibility mode will not allow mixing of domain, the base backward compatibility mode will not allow mixing of
LSA formats. Different formats could still be supported with LSA formats. Different formats could still be supported with
multiple OSPFv3 instances and separate OSPFv3 routing domains. multiple OSPFv3 instances and separate OSPFv3 routing domains.
Additionally, a more complex mode is provided in Section 12.1, where Additionally, a more complex mode is provided in Section 12.1, where
both formats of LSA coexist. An OSPFv3 instance will be configured both formats of LSA coexist. In order to facilitate backward
to use either the Non-TLV-based LSAs, TLV-based LSAs, or support both compatibility, the OSPFv3 options field (as described in Appendix A.2
(Appendix A). In order to facilitate backward compatibility, the of RFC 5340 [OSPFV3]), will contain an additional options bits. The
OSPFv3 options field (as described in Appendix A.2 of RFC 5340 EL-bit will be used to indicate that the advertising OSPFv3 Router
[OSPFV3]), will contain an additional options bits. The EL-bit will can receive, process, and originate TLV-based LSAs. An OSPFv3 router
be used to indicate that the advertising OSPFv3 Router can receive, configured to support TLV-based LSAs WILL set its option field EL-bit
process, and originate TLV-based LSAs. An OSPFv3 router configured in OSPFv3 Hello and Database Description packets. If Full is
to support TLV-based LSAs WILL set its option field EL-bit in OSPFv3 specified for ExtendedLSASupport, the OSPFv3 router MUST NOT form
Hello and Database Description packets. If "Normal" is specified for adjacencies with OSPFv3 Routers sending OSPFv3 Hello and Database
ExtendedLSASupport, the OSPFv3 router MUST NOT form adjacencies with Description packets with the options field EL-bit clear. In this
OSPFv3 Routers sending OSPFv3 Hello and Database Description packets manner, OSPFv3 routing domains utilizing the new encoding will be
with the options field EL-bit clear. In this manner, OSPFv3 routing completely isolated from those using the RFC 5340 encodings.
domains utilizing the new encoding will be completely isolated from
those using the RFC 5340 encodings. If MixedModeOriginateOnly, MixedModeOriginateSPF, or Full is
specified for ExtendedLSASupport, (Appendix A), or
AreaExtendedLSASupport (Appendix B) the EL-bit will be set in the
OSPFv3 Hello and Database Description packet options field.
1 2 1 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 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
+-+-+-+-+-+-+-+-+-+-+-+-+--+--+-+--+-+-+--+-+-+-+--+--+ +-+-+-+-+-+-+-+-+-+-+-+-+--+--+-+--+-+-+--+-+-+-+--+--+
| | | | | | | | | | | | |EL|AT|L|AF|*|*|DC|R|N|x| E|V6| | | | | | | | | | | | | |EL|AT|L|AF|*|*|DC|R|N|x| E|V6|
+-+-+-+-+-+-+-+-+-+-+-+-+--+--+-+--+-+-+--+-+-+-+--+--+ +-+-+-+-+-+-+-+-+-+-+-+-+--+--+-+--+-+-+--+-+-+-+--+--+
The Options field The Options field
EL-bit EL-bit
This bit is indicates whether or not the OSPFv3 router This bit is indicates whether or not the OSPFv3 router
supports the Extended LSA format with the bit set condition supports the Extended LSA format with the bit set condition
indicating support. indicating support.
Options Field EL-bit Options Field EL-bit
12.1. Extended LSA Mixed-Mode Backward Compatibility 12.1. Extended LSA Mixed-Mode Backward Compatibility
An implementation MAY support configuration allowing a mixture of An implementation MAY support configuration allowing a graceful
OSPFv3 routers supporting and not supporting TLV-based LSAs in the transition from the non-extended (non-TLV-based) LSAs to the extended
same OSPFv3 routing domain. In these deployments, the OSPFv3 routers (TLV-based) LSAs in an OSPFv3 routing domain. In these routing
configured with a value of MixedMode or MixedModeDegraded for domains, the OSPFv3 routers configured with a value of
ExtendedLSASupport, (Appendix A), MUST originate both the TLV-based MixedModeOriginateOnly or MixedModeOriginateSPF for
and non-TLV-based versions of the OSPFv3 LSAs described herein. For ExtendedLSASupport, (Appendix A), MUST originate both the extended
the purposes of Shortest Path First (SPF) computation, if the and non-extended versions of the OSPFv3 LSAs described herein. For
configured value is MixedMode, the TLV-based LSAs MUST be used by the purposes of Shortest Path First (SPF) computation, the non-
OSPFv3 routers supporting this specification. If MixedModeDegraded exteneded versions of the OSPFv3 LSAs are used for SPF computation
is configured, the non-TLV-based versions of the OSPFv3 LSAs are used when MixedModeOrignateOnly is configured and the extended versions
for SPF computation. OSPFv3 routers configured for mixed mode are used when MixedModeOriginateSPF is specified. The extended LSAs
operation also MUST form adjacencies with OSPFv3 Routers sending MAY be used for functions other than routing computation as long as
OSPFv3 Hello and Database Description packets with the options field backward compatility is described in the documents describing those
EL-bit clear. In this manner, OSPFv3 routing domains utilizing the functions. OSPFv3 routers configured for mixed mode operation also
new encodings can be gradually migrated with a worst-case cost of MUST form adjacencies with OSPFv3 Routers sending OSPFv3 Hello and
approximately doubling the number of LSAs in the routing domain. Database Description packets with the options field EL-bit clear.
In this manner, OSPFv3 routing domains utilizing the new encodings
can be gradually migrated with a worst-case cost of approximately
doubling the number of LSAs in the routing domain. The transition
within an OSPFv3 routing domain would progress as follows:
1. Configure OSPFv3 Router ExtendedLSASupport to
MixedModeOriginateOnly so that routers orginate the extended
LSAs.
2. When all the OSPFv3 Routers have been reconfigured to
MixedModeOriginateOnly, gradually reconfigure OSPFv3 Routers to
use the extended LSAs by configuring ExtendedLSASupport to
MixedModeOriginateSPF. This can be done on a small subset of
OSPFv3 Routers and the route tables can be verified.
3. When all the OSPFv3 Routers have been reconfigured to
MixedModeOriginateSPF and the routing has been verified,
reconfigure OSPFv3 Routers to purge or simply not refresh the
non-extended OSPFv3 LSA by configuring ExtendedLSASupport to
Full.
12.1.1. Area Extended LSA Mixed-Mode Backward Compatibility
An implemenation MAY also support configuration allowing graceful
transition from the non-extended LSAs to the extended LSAs within a
single area. In these area, the parameter AreaExtendedLSASupport
(Appendix B) may be configured to take precedence over the global
parameter ExtendedLSASupport. However, the AreaExtendedLSASupport
will only apply to link and area scoped LSAs within the area and area
based SPF calculations. The default is for the
AreaExtendedLSASupport to be inherited from the ExtendedLSASupport.
12.2. LSA TLV Processing Backward Compatibility 12.2. LSA TLV Processing Backward Compatibility
This section defines the general rules for processing LSA TLVs. To This section defines the general rules for processing LSA TLVs. To
ensure compatibility of future TLV-based LSA extensions, all ensure compatibility of future TLV-based LSA extensions, all
implementations MUST adhere to these rules: implementations MUST adhere to these rules:
1. Unrecognized TLVs and sub-TLVs are ignored when parsing or 1. Unrecognized TLVs and sub-TLVs are ignored when parsing or
processing Extended-LSAs. processing Extended-LSAs.
skipping to change at page 29, line 5 skipping to change at page 30, line 5
[MT-OSPFV3] [MT-OSPFV3]
Mirtorabi, S. and A. Roy, "Multi-topology routing in Mirtorabi, S. and A. Roy, "Multi-topology routing in
OSPFv3 (MT-OSPFV3)", draft-ietf-ospf-mt-ospfv3-04.txt OSPFv3 (MT-OSPFV3)", draft-ietf-ospf-mt-ospfv3-04.txt
(work in progress). (work in progress).
[OSPF-DIGITAL-SIGNATURE] [OSPF-DIGITAL-SIGNATURE]
Murphy, S., Badger, M., and B. Wellington, "OSPF with Murphy, S., Badger, M., and B. Wellington, "OSPF with
Digital Signatures", RFC 2154, June 1997. Digital Signatures", RFC 2154, June 1997.
Appendix A. Configurable Constants Appendix A. Global Configuration Parameters
An additional global configurable constant will be added to the An additional global configurable parameter will be added to the
OSPFv3 protocol. OSPFv3 protocol.
ExtendedLSASupport ExtendedLSASupport
This is an enumeration type indicating the extent to which the This is an enumeration type indicating the extent to which the
OSPFv3 instance supports the TLV format described herein for OSPFv3 instance supports the TLV format described herein for
Extended LSAs. The valid value for the enumeration are: Extended LSAs. The valid value for the enumeration are:
* None - Non-extended LSAs will not be originated or used in the * None - Non-extended LSAs will not be originated or used in the
SPF calculation. SPF calculation. This is the default.
* Normal - Extended LSAs will be originated and adjacencies will * MixedModeOriginateOnly - Both extended and non-extended LSAs
will be originated. OSPFv3 adjacencies will be formed with
OSPFv3 routers not supporting this specification. The non-
extended LSAs are used for the SPF computation.
* MixedModeOriginateSPF - Both extended and non-extended LSAs
will be originated. OSPFv3 adjacencies will be formed with
OSPFv3 routers not supporting this specification. The extended
LSAs are used for the SPF computation.
* Full - Extended LSAs will be originated and adjacencies will
not be formed with OSPFv3 routers not supporting this not be formed with OSPFv3 routers not supporting this
specification. specification. Only Extended LSAs will be originated.
* MixedMode - Both extended and non-extended LSAs will be Appendix B. Area Configuration Parameters
originated. OSPFv3 adjacencies will be formed with OSPFv3
routers not supporting this specification. The extended LSAs
are used for the SPF computation.
* MixedModeDegraded - Both extended and non-extended LSAs will be An additional area configurable parameter will be added to the OSPFv3
originated. OSPFv3 adjacencies will be formed with OSPFv3 protocol.
routers not supporting this specification. The non-extended
LSAs are used for the SPF computation. AreaExtendedLSASupport
This is an enumeration type indicating the extent to which the
OSPFv3 area supports the TLV format described herein for Extended
LSAs. The valid value for the enumeration are:
* InheritGlobal - The AreaExtendedLSASupport will be inherited
from ExtendedLSASupport. This is the default.
* None - Non-extended LSAs will not be originated or used in the
SPF calculation.
* MixedModeOriginateOnly - Both extended and non-extended link
and area scoped LSAs will be originated. OSPFv3 adjacencies
will be formed with OSPFv3 routers not supporting this
specification. The non-extended LSAs are used for the SPF
computation.
* MixedModeOriginateSPF - Both extended and non-extended link and
area scoped LSAs will be originated. OSPFv3 adjacencies will
be formed with OSPFv3 routers not supporting this
specification. The extended LSAs are used for the area SPF
computation.
* Full - Link and area scoped extended LSAs will be originated
and adjacencies will not be formed with OSPFv3 routers not
supporting this specification. Only Extended LSAs will be
originated.
For regular areas, i.e., areas where AS scoped LSAs are flooded,
configuring None or MixedModeOriginateOnly for AreaExtendedLSASupport
when Full is specified for ExtendedLSASupport is contradictory and
MAY be prohibited by the implementation.
Authors' Addresses Authors' Addresses
Acee Lindem Acee Lindem
Ericsson Ericsson
301 Midenhall Way 301 Midenhall Way
Cary, NC 27513 Cary, NC 27513
USA USA
Email: acee.lindem@ericsson.com Email: acee.lindem@ericsson.com
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