draft-ietf-ospf-lls-01.txt   draft-ietf-ospf-lls-02.txt 
OSPF Working Group Alex Zinin Network Working Group A. Zinin
Internet Draft Alcatel Internet-Draft Alcatel
Expiration Date: December 2006 Barry Friedman Intended status: Standards Track B. Friedman
File name: draft-ietf-ospf-lls-01.txt Abhay Roy Expires: July 13, 2007 A. Roy
Liem Nguyen L. Nguyen
Derek Yeung D. Young
Cisco Systems Cisco Systems
January 9, 2007
OSPF Link-local Signaling OSPF Link-local Signaling
draft-ietf-ospf-lls-01.txt draft-ietf-ospf-lls-02.txt
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). Copyright (C) The Internet Society (2007).
Abstract Abstract
OSPF is a link-state intra-domain routing protocol. OSPF routers OSPF is a link-state intra-domain routing protocol. OSPF routers
exchange information on a link using packets that follow a exchange information on a link using packets that follow a well-
well-defined fixed format. The format is not flexible enough to defined fixed format. The format is not flexible enough to enable
enable new features which need to exchange arbitrary data. This memo new features which need to exchange arbitrary data. This memo
describes a backward-compatible technique to perform link-local describes a backward-compatible technique to perform link-local
signaling, i.e., exchange arbitrary data on a link. signaling, i.e., exchange arbitrary data on a link.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conventions Used In This Document . . . . . . . . . . . . 3
2. Proposed solution . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Options Field . . . . . . . . . . . . . . . . . . . . . . 5
2.2. LLS Data Block . . . . . . . . . . . . . . . . . . . . . . 5
2.3. LLS TLVs . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4. Extended Options TLV . . . . . . . . . . . . . . . . . . . 6
2.5. Cryptographic Authentication TLV (OSPFv2 ONLY) . . . . . . 7
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
4. Compatibility Issues . . . . . . . . . . . . . . . . . . . . . 10
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.1. Normative References . . . . . . . . . . . . . . . . . . . 12
6.2. Informative References . . . . . . . . . . . . . . . . . . 12
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
Intellectual Property and Copyright Statements . . . . . . . . . . 15
1. Introduction 1. Introduction
This document describes an extension to OSPFv2 [OSPFV2] and OSPFv3 This document describes an extension to OSPFv2 [OSPFV2] and OSPFv3
[OSPFV3] allowing additional information to be exchanged between [OSPFV3] allowing additional information to be exchanged between
routers on the same link. OSPFv2 and OSPFv3 packet formats are fixed routers on the same link. OSPFv2 and OSPFv3 packet formats are fixed
and do not allow for extension. This document proposes appending an and do not allow for extension. This document proposes appending an
optional data block composed of Type/Length/Value (TLV) triplets to optional data block composed of Type/Length/Value (TLV) triplets to
existing OSPFv2 and OSPFv3 packets to carry this additional existing OSPFv2 and OSPFv3 packets to carry this additional
information. Throughout this document, OSPF will be used when the information. Throughout this document, OSPF will be used when the
specification is applicable to both OSPFv2 and OSPFv3. Similarly, specification is applicable to both OSPFv2 and OSPFv3. Similarly,
OSPFv2 or OSPFv3 will be used when the text is protocol specific. OSPFv2 or OSPFv3 will be used when the text is protocol specific.
One potential way of solving this task could be introducing a new One potential way of solving this task could be introducing a new
packet type. However, that would mean introducing extra packets on packet type. However, that would mean introducing extra packets on
the network which may not be desirable and may cause backward the network which may not be desirable and may cause backward
compatibility issues. This document describes how to exchange data compatibility issues. This document describes how to exchange data
using standard OSPF packet types. using standard OSPF packet types.
1.1 Conventions Used In This Document 1.1. Conventions Used In This Document
In this document, the key words "MUST", "MUST NOT", "REQUIRED", In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in RFC2119 [KEY]. and "OPTIONAL" are to be interpreted as described in RFC2119 [KEY].
2. Proposed solution 2. Proposed solution
To perform link-local signaling (LLS), OSPF routers add a special To perform link-local signaling (LLS), OSPF routers add a special
data block at the end of OSPF packets or right after the data block at the end of OSPF packets or right after the
authentication data block when cryptographic authentication is used. authentication data block when cryptographic authentication is used.
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. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Format of LLS Data Block Figure 3: Format of LLS Data Block
The Checksum field contains the standard IP checksum of the entire The Checksum field contains the standard IP checksum of the entire
contents of the LLS block. contents of the LLS block.
The 16-bit LLS Data Length field contains the length (in 32-bit The 16-bit LLS Data Length field contains the length (in 32-bit
words) of the LLS block including the header and payload. words) of the LLS block including the header and payload.
Implementations MUST NOT use the Length field in the IP packet Implementations MUST NOT use the Length field in the IP packet header
header to determine the length of the LLS data block. to determine the length of the LLS data block.
Note that if the OSPF packet is cryptographically authenticated, the Note that if the OSPF packet is cryptographically authenticated, the
LLS data block MUST also be cryptographically authenticated. In this LLS data block MUST also be cryptographically authenticated. In this
case the regular LLS checksum is not calculated and the LLS block case the regular LLS checksum is not calculated and the LLS block
will contain a cryptographic authentication TLV (see Section 2.6). will contain a cryptographic authentication TLV (see Section 2.5).
The rest of the block contains a set of Type/Length/Value (TLV) The rest of the block contains a set of Type/Length/Value (TLV)
triplets as described in Section 2.3. All TLVs MUST be 32-bit triplets as described in Section 2.3. All TLVs MUST be 32-bit
aligned (with padding if necessary). aligned (with padding if necessary).
2.3. LLS TLVs 2.3. LLS TLVs
The contents of LLS data block is constructed using TLVs. See Figure The contents of LLS data block is constructed using TLVs. See Figure
4 for the TLV format. 4 for the TLV format.
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. Value . . Value .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Format of LLS TLVs Figure 4: Format of LLS TLVs
Note that TLVs are always padded to 32-bit boundary, but padding Note that TLVs are always padded to 32-bit boundary, but padding
bytes are not included in TLV Length field (though it is included in bytes are not included in TLV Length field (though it is included in
the LLS Data Length field of the LLS block header). the LLS Data Length field of the LLS block header).
2.5. Extended Options TLV 2.4. Extended Options TLV
This subsection describes a TLV called Extended Options (EO) TLV. This subsection describes a TLV called Extended Options (EO) TLV.
The format of EO-TLV is shown in Figure 5. The format of EO-TLV is shown in Figure 5.
Bits in the Value field do not have any semantics from the point of Bits in the Value field do not have any semantics from the point of
view of LLS mechanism. This field MAY be used to announce some OSPF view of LLS mechanism. This field MAY be used to announce some OSPF
capabilities that are link-specific. Also, other OSPF extensions MAY capabilities that are link-specific. Also, other OSPF extensions MAY
allocate bits in the bit vector to perform boolean link-local allocate bits in the bit vector to perform boolean link-local
signaling. signaling.
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| Extended Options | | Extended Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Format of EO TLV Figure 5: Format of EO TLV
Currently, [OOB] and [RESTART] use bits in the Extended Options field Currently, [OOB] and [RESTART] use bits in the Extended Options field
of the EO-TLV. of the EO-TLV.
The Extended Options bits are defined in Section 3. The Extended Options bits are defined in Section 3.
2.6. Cryptographic Authentication TLV (OSPFv2 ONLY) 2.5. Cryptographic Authentication TLV (OSPFv2 ONLY)
This document defines a special TLV that is used for cryptographic This document defines a special TLV that is used for cryptographic
authentication (CA-TLV) of the LLS data block. This TLV MUST be authentication (CA-TLV) of the LLS data block. This TLV MUST be
included in the LLS block when the cryptographic (MD5) authentication included in the LLS block when the cryptographic (MD5) authentication
is enabled on the corresponding interface. The message digest of the is enabled on the corresponding interface. The message digest of the
LLS block MUST be calculated using the same key and authentication LLS block MUST be calculated using the same key and authentication
algorithm, as that used for the main OSPFv2 packet. The cryptographic algorithm, as that used for the main OSPFv2 packet. The
sequence number is included in the TLV and MUST be the same as the cryptographic sequence number is included in the TLV and MUST be the
one in the main OSPFv2 packet for the LLS block to be considered same as the one in the main OSPFv2 packet for the LLS block to be
authentic. considered authentic.
The TLV is constructed as shown Figure 6. The TLV is constructed as shown Figure 6.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 2 | AuthLen | | 2 | AuthLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence number | | Sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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4. Compatibility Issues 4. Compatibility Issues
The modifications to OSPF packet formats are compatible with standard The modifications to OSPF packet formats are compatible with standard
OSPF because LLS-incapable routers will not consider the extra data OSPF because LLS-incapable routers will not consider the extra data
after the packet; i.e., the LLS data block will be ignored by routers after the packet; i.e., the LLS data block will be ignored by routers
which do not support the LLS extension. which do not support the LLS extension.
5. Security Considerations 5. Security Considerations
The described technique provides the same level of security as OSPF The described technique provides the same level of security as OSPF
protocol by allowing LLS data to be authenticated (see Section 2.6 protocol by allowing LLS data to be authenticated (see Section 2.5
for more details). for more details).
OSPFv3 has IPSec authentication built in. There are AH/ESP techniques OSPFv3 has IPSec authentication built in. There are AH/ESP
which operate on the whole OSPFv3 payload. So we do not need a techniques which operate on the whole OSPFv3 payload. So we do not
separate cryptographic TLV for OSPFv3. need a separate cryptographic TLV for OSPFv3.
6. Acknowledgements 6. References
The authors would like to acknowledge Russ White and Acee Lindem for 6.1. Normative References
their thoughtful review of this document.
7. References [IANA] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 2334,
October 1998.
7.1 Normative References [KEY] Bradner, S., "Key words for use in RFC's to Indicate
Requirement Levels", RFC 2119, March 1997.
[OSPFV2] Moy, J., "OSPF Version 2", RFC 2328, April 1998. [OSPFV2] Moy, J., "OSPF Version 2", RFC 2328, April 1998.
[OSPFV3] R. Coltun, D. Ferguson and J. Moy, "OSPF for IPv6",
[OSPFV3] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6",
RFC 2740, December 1999. RFC 2740, December 1999.
[KEY] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[IANA] Narten, T., and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", RFC 2434, October 1998.
7.2 Informative References 6.2. Informative References
[OOB] Zinin, A., Roy, A. and L. Nguyen, [OOB] Zinin, A., Roy, A., and L. Nguyen, "OSPF Out-of-band LSDB
"OSPF Out-of-band LSDB resynchronization", resynchronization", draft-nguyen-ospf-oob-resync-06.txt
Work in progress, September 2004. (work in progress), October 2006.
[RESTART] Zinin, A., Roy, A. and L. Nguyen, "OSPF Restart Signaling", [RESTART] Zinin, A., Roy, A., and L. Nguyen, "OSPF Restart
Work in progress, September 2004. Signaling", draft-nguyen-ospf-restart-06.txt (work in
progress), October 2006.
8. Author Information Appendix A. Acknowledgements
The authors would like to acknowledge Russ White and Acee Lindem for
their thoughtful review of this document.
Authors' Addresses
Alex Zinin
Alcatel
Sunnyvale
USA
Email: zinin@psg.com
Alex Zinin Abhay Roy
Alcatel Cisco Systems
Sunnyvale, CA 170 W. Tasman Dr.
USA San Jose,CA 95134
E-mail: zinin@psg.com USA
E-mail: akr@cisco.com
Barry Friedman Barry Friedman
Cisco Systems Derek M. Yeung Cisco Systems
170 W. Tasman Dr. Cisco Systems 170 West Tasman Drive
San Jose,CA 95134 170 W. Tasman Dr. San Jose, CA 95134
USA San Jose,CA 95134 USA
E-mail: friedman@cisco.com USA
E-mail: myeung@cisco.com Email: friedman@cisco.com
Abhay Roy
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134
USA
Email: akr@cisco.com
Liem Nguyen Liem Nguyen
Cisco Systems Cisco Systems
170 W. Tasman Dr. 170 West Tasman Drive
San Jose,CA 95134 San Jose,CA 95134
USA USA
E-mail: lhnguyen@cisco.com
Intellectual Property Statement Email: lhnguyen@cisco.com
Derek Young
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134
USA
Email: myeung@cisco.com
Full Copyright Statement
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ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
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Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is provided by the IETF
Internet Society. Administrative Support Activity (IASA).
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