One document matched: draft-akiya-bfd-seamless-ip-01.txt
Differences from draft-akiya-bfd-seamless-ip-00.txt
Internet Engineering Task Force N. Akiya
Internet-Draft C. Pignataro
Intended status: Standards Track D. Ward
Expires: June 8, 2014 Cisco Systems
December 5, 2013
Seamless Bidirectional Forwarding Detection (BFD) for IP
draft-akiya-bfd-seamless-ip-01
Abstract
This specification defines procedures to use Seamless Bidirectional
Forwarding Detection (S-BFD) in IP and IP signalled MPLS
environments.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 8, 2014.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. BFD Target Identifier Type . . . . . . . . . . . . . . . . . 2
3. Reserved BFD Discriminators . . . . . . . . . . . . . . . . . 3
4. BFD Target Identifier Table . . . . . . . . . . . . . . . . . 3
5. Full Reachability Validations . . . . . . . . . . . . . . . . 3
5.1. Initiator Behavior . . . . . . . . . . . . . . . . . . . 4
5.2. Responder Behavior . . . . . . . . . . . . . . . . . . . 4
6. Partial Reachability Validations . . . . . . . . . . . . . . 4
7. MPLS Label Verifications . . . . . . . . . . . . . . . . . . 4
8. Provisioning Active IP Sessions . . . . . . . . . . . . . . . 4
9. Security Considerations . . . . . . . . . . . . . . . . . . . 5
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
12. Contributing Authors . . . . . . . . . . . . . . . . . . . . 5
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
13.1. Normative References . . . . . . . . . . . . . . . . . . 5
13.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
One application for Seamless Bidirectional Forwarding Detection
(S-BFD) [I-D.akiya-bfd-seamless-base] is to perform full and partial
reachability validations on IP and IP signalled MPLS environments.
This specification defines procedures to use Seamless BFD in IP and
IP signalled MPLS environments.
2. BFD Target Identifier Type
BFD target identifier type of value 1 is used for IPv4 addresses and
router IDs. This identifier type will cover Seamless BFD in
following scenarios:
o BFD control packets IPv4 routed.
o BFD control packets IPv6 routed.
o BFD control packets label switched in IPv4 signaled LSP.
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o BFD control packets label switched in IPv6 signaled LSP.
Not all IPv6 aspects are covered by this specification, and details
are clarified in Section 3.
3. Reserved BFD Discriminators
With IPv4 based BFD, BFD target identifier type 1 is used. IPv4
addresses are used as BFD discriminators. BFD discriminator values
corresponding to all or subset of local IPv4 addresses are to be
allocated from the discriminator pool for Seamless BFD.
Example:
o BFD Target Identifier Type 1: IPv4 address 3.3.2.1 maps to BFD
discriminator 0x03030201.
With IPv6 based BFD, BFD target identifier type 1 is used. Router
IDs are used as BFD discriminators. BFD discriminator values
corresponding to all or subset of local router IDs are to be
allocated from the discriminator pool for Seamless BFD. IDs which
are larger than 32 bits (ex: ISIS system ID) are not included as part
of this identifier type, and is outside the scope of this document.
Example:
o BFD Target Identifier Type 1: Router-ID 3.3.4.5 maps to BFD
discriminator 0x03030405.
Note that it is acceptable for an IPv4 address and a router-ID to
collide, mapping into a same BFD discriminator value. There will not
be an issue as long as colliding BFD discriminator value is reserved
for the Seamless BFD purpose.
4. BFD Target Identifier Table
With IP identifier type, only locally reserved BFD discriminators and
corresponding information are to be in this table. No inter-node
communications are needed to exchange BFD discriminator and BFD
target identifier mappings.
5. Full Reachability Validations
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5.1. Initiator Behavior
Any IP network node can attempt to perform a full reachability
validation to any BFD target identifier of type 1 (IPv4 address or
router-ID) on other network nodes, as long as destination BFD target
identifier is provisioned to use this mechanism. Transmitted BFD
control packet by the initiator is to have "your discriminator"
corresponding to destination IPv4 address or router ID.
Initiator is to use following procedures to construct BFD control
packets to perform IP full reachability validations on BFD packets
that are IP routed:
o MUST set "your discriminator" to target IPv4 address or target
router-ID.
o If packet is to be explicitly label switched, then explicit label
switching packet format described in [I-D.akiya-bfd-seamless-base]
MUST be used. Otherwise IP routing packet format described in
[I-D.akiya-bfd-seamless-base] MUST be used.
5.2. Responder Behavior
To respond to received BFD control packet which was targeted to local
BFD target identifier of type 1 (IP address or router-ID), response
BFD control packet is targeted to IP address taken from received
"source IP address". Responder MUST validate obtained IP address is
in valid format (ex: not Martian address). Responder MUST consult
local routing table to ensure obtained IP address is reachable.
6. Partial Reachability Validations
Procedures described in [I-D.akiya-bfd-seamless-base] applies.
7. MPLS Label Verifications
MPLS label verification mechanism is applicable to those IP based BFD
which use explicit label switching techniques. However, details of
what responder embeds in the lower 23 bits of localhost address, and
how initiator determines correctness of label programming is outside
the scope of this document.
8. Provisioning Active IP Sessions
Active IP BFD sessions, single-hop, multi-hop or MPLS can be
instantiated on any network node to any IPv4 target addresses and
OSPFv3 router IDs using this mechanism. This style of usage is
particularly useful only if one side is required to perform full
reachability validations (ex: static route, uni-directional tunnel).
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This style of usage is also particularly useful to perform
validations and verifications on just subset of LSPs (ex: inter-AS,
injection of partial BFD reachability validation packet on IPv4 RSVP
LSP nodes).
9. Security Considerations
Security considerations for BFD are discussed in [RFC5880] and
security considerations for S-BFD are discussed in
[I-D.akiya-bfd-seamless-base].
10. IANA Considerations
None
11. Acknowledgements
Authors would like to thank Marc Binderberger from Cisco Systems for
providing valuable comments.
12. Contributing Authors
Tarek Saad
Cisco Systems
Email: tsaad@cisco.com
Siva Sivabalan
Cisco Systems
Email: msiva@cisco.com
Nagendra Kumar
Cisco Systems
Email: naikumar@cisco.com
13. References
13.1. Normative References
[I-D.akiya-bfd-seamless-base]
Akiya, N., Pignataro, C., Ward, D., Bhatia, M., and J.
Networks, "Seamless Bidirectional Forwarding Detection
(BFD) with MPLS Label Verification Extension", draft-
akiya-bfd-seamless-base-02 (work in progress), October
2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, June 2010.
13.2. Informative References
[RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, June
2010.
[RFC5883] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for Multihop Paths", RFC 5883, June 2010.
[RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
"Bidirectional Forwarding Detection (BFD) for MPLS Label
Switched Paths (LSPs)", RFC 5884, June 2010.
Authors' Addresses
Nobo Akiya
Cisco Systems
Email: nobo@cisco.com
Carlos Pignataro
Cisco Systems
Email: cpignata@cisco.com
Dave Ward
Cisco Systems
Email: wardd@cisco.com
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