Internet DRAFT - draft-xu-isis-service-sid-adv
draft-xu-isis-service-sid-adv
Network Working Group X. Xu
Internet-Draft Huawei
Intended status: Standards Track April 22, 2014
Expires: October 24, 2014
Signaling Services and Service SIDs Using IS-IS
draft-xu-isis-service-sid-adv-00
Abstract
The Segment Routing mechanism can be leveraged to realize the service
path layer functionality of the Service Function Chaining (i.e,
steering traffic through the service function path). This document
describes how to advertise services and the corresponding service
segment IDs using IS-IS.
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 October 24, 2014.
Copyright Notice
Copyright (c) 2014 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
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.
Xu Expires October 24, 2014 [Page 1]
Internet-Draft April 2014
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Advertising Services and Service SIDs . . . . . . . . . . . . 2
3.1. Service Sub-TLVs . . . . . . . . . . . . . . . . . . . . 3
3.2. Service SID Sub-TLVs . . . . . . . . . . . . . . . . . . 3
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
[I-D.xu-spring-sfc-use-case] describes a particular use case for
SPRING where the Segment Routing (SR) mechanism is leveraged to
realize the service path layer functionality of the SFC (i.e,
steering traffic through the service function path). To allow the
service classifier to encode the segment list represeting a
particular service path, the classifier needs to know on which
service node(s) a given service is located and what segment ID (SID)
is used to indicate that service on a given service node. This
document describes how to advertise services and the corresponding
service SIDs using IS-IS.
1.1. 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].
2. Terminology
This memo makes use of the terms defined in [RFC4971].
3. Advertising Services and Service SIDs
Service nodes within the network need to advertise each service they
are offering by using a new sub-TLV of the IS-IS Router CAPABILITY
TLV defined in [RFC4971]. These sub-TLVs are called as Service sub-
TLVs. The scope of the advertisement depends on the application but
it is recommended that it SHOULD be domain-wide. Furthermore, they
may need to allocate at least one corresponding SID for each service
and meanwhile advertise it by using a sub-TLV of the corresponding
Xu Expires October 24, 2014 [Page 2]
Internet-Draft April 2014
Service sub-TLV for that service, called Service SID sub-TLV. In the
MPLS-SR case, service nodes within the network would allocate a
locally significant MPLS label to each service they are offering. In
the IPv6-SR case, service nodes within the network would allocate a
locally unique link-local IPv6 address to each service they are
offering. For a given service, the service node offering that
service could advertise the service ID in MPLS label format or the
one in IPv6 address format, or both.
3.1. Service Sub-TLVs
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Sub-TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: each service is allocated with a unique type code.
Length: variable
Value: contains zero or more sub-TLVs. Besides the Service SID
sub-TLVs, other sub-TLVs (to be defined in future) which are used
to describe some characters of a service could also be contained
in this field.
3.2. Service SID Sub-TLVs
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Service SID ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD1 for the service SID in MPLS label format and TBD2 for
the service SID in IPv6 address format.
Length: variable (3 or 16).
Value: if the Length is set to 3, the 20 rightmost bits represent
a MPLS label. If the length is set to 16, the value represents an
IPv6 address.
Xu Expires October 24, 2014 [Page 3]
Internet-Draft April 2014
4. Acknowledgements
TBD .
5. IANA Considerations
TBD.
6. Security Considerations
This document does not introduce any new security risk.
7. References
7.1. Normative References
[I-D.filsfils-spring-segment-routing-mpls]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R.,
Ytti, S., Henderickx, W., Tantsura, J., and E. Crabbe,
"Segment Routing with MPLS data plane", draft-filsfils-
spring-segment-routing-mpls-01 (work in progress), April
2014.
[I-D.previdi-6man-segment-routing-header]
Previdi, S., Filsfils, C., Field, B., and I. Leung, "IPv6
Segment Routing Header (SRH)", draft-previdi-6man-segment-
routing-header-00 (work in progress), March 2014.
[I-D.quinn-sfc-arch]
Quinn, P. and A. Beliveau, "Service Function Chaining
(SFC) Architecture", draft-quinn-sfc-arch-04 (work in
progress), January 2014.
[I-D.quinn-sfc-nsh]
Quinn, P., Guichard, J., Fernando, R., Surendra, S.,
Smith, M., Yadav, N., Agarwal, P., Manur, R., Chauhan, A.,
Elzur, U., McConnell, B., and C. Wright, "Network Service
Header", draft-quinn-sfc-nsh-02 (work in progress),
February 2014.
[I-D.rijsman-sfc-metadata-considerations]
Rijsman, B. and J. Moisand, "Metadata Considerations",
draft-rijsman-sfc-metadata-considerations-00 (work in
progress), February 2014.
Xu Expires October 24, 2014 [Page 4]
Internet-Draft April 2014
[I-D.xu-spring-sfc-use-case]
Xu, X., "Service Function Chaining Use Case", draft-xu-
spring-sfc-use-case-00 (work in progress), April 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4971] Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate
System to Intermediate System (IS-IS) Extensions for
Advertising Router Information", RFC 4971, July 2007.
7.2. Informative References
[I-D.filsfils-rtgwg-segment-routing]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R.,
Ytti, S., Henderickx, W., Tantsura, J., and E. Crabbe,
"Segment Routing Architecture", draft-filsfils-rtgwg-
segment-routing-01 (work in progress), October 2013.
Author's Address
Xiaohu Xu
Huawei
Email: xuxiaohu@huawei.com
Xu Expires October 24, 2014 [Page 5]
