Internet DRAFT - draft-xu-isis-service-function-adv
draft-xu-isis-service-function-adv
ISIS Working Group X. Xu
Internet-Draft N. Wu
Intended status: Standards Track Huawei
Expires: November 11, 2017 H. Shah
Ciena
L. Contreras
Telefonica I+D
May 10, 2017
Advertising Service Functions Using IS-IS
draft-xu-isis-service-function-adv-05
Abstract
The MPLS source routing mechanism developed by Source Packet Routing
in Networking (SPRING) WG can be leveraged to realize a unified
source routing instruction which works across both IPv4 and IPv6
underlays in addition to the MPLS underlay. The unified source
routing instruction can be used to realize a transport-independent
service function chaining by encoding the service function path
information or service function chain information as an MPLS label
stack. This document describes how to advertise service functions
and their corresponding attributes (e.g., service function label)
using IS-IS.
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 November 11, 2017.
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Copyright Notice
Copyright (c) 2017 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
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Solution Description . . . . . . . . . . . . . . . . . . . . 3
3.1. Service Function Sub-TLV . . . . . . . . . . . . . . . . 3
3.2. SF Label Sub-TLV . . . . . . . . . . . . . . . . . . . . 4
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
[I-D.xu-mpls-service-chaining] describes how to leverage the unified
source routing instruction
[I-D.xu-mpls-unified-source-routing-instruction] to realize a
transport-independent service function chaining by encoding the
Service Function Path (SFP) or Service Function Chain (SFC)
information as an MPLS label stack. To allow a service classifier to
attach the MPLS label stack which represents a particular SFP or SFC
to the selected traffic, the service classifier needs to know on
which Service Function Forwarder (SFF) a given Service Function (SF)
is located and what service function label is used to indicate that
SF. This document describes how to advertise SFs and their
corresponding attributes (e.g., service function label) using IS-IS.
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2. Terminology
This memo makes use of the terms defined in
[I-D.xu-mpls-service-chaining] and [RFC4971].
3. Solution Description
SFFs within the SFC domain need to advertise each SF they are
offering by using a new sub-TLV of the IS-IS Router CAPABILITY TLV
[RFC4971]. This new sub-TLV is called as Service Function sub-TLV.
The Service Function sub-TLV could appear multiple times wihin a
given IS-IS Router CAPABILITY TLV when more than one SF needs to be
advertised. The scope of the advertisement depends on the
application but it is recommended that it SHOULD be domain-wide. To
support the approach of encoding SFP information in the form of an
MPLS label stack as described in [I-D.xu-mpls-service-chaining], SFFs
SHOULD allocate a locally significant MPLS label to each SF they are
offering. Therefore, SFFs need to advertise the corresponding
service function label to each SF they are offering by using a sub-
TLV of the above Service Function sub-TLV, called SF Label sub-TLV.
3.1. Service Function Sub-TLV
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=TBD1 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Function Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Sub-TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD1.
Length: variable.
Service Function Identifier: A unique identifier that represents
an SF within an SFC-enabled domain.
Sub-TLVs: contains zero or more sub-TLVs corresponding to the
particular attributes of a given SF. The SF Label sub-TLV as
defined in Section 3.2 is one such sub-TLV. Other sub-TLVs are to
be defined in the future.
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3.2. SF Label Sub-TLV
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=TBD2 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Resv | SF Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD2.
Length: 3.
Value: The rightmost 20 bits represent an MPLS label which is the
SF Label of the corresponding SF.
4. Acknowledgements
TBD.
5. IANA Considerations
This document includes a request to IANA for allocating type codes
for the Service Function sub-TLV and the SF Label sub-TLV.
6. Security Considerations
This document does not introduce any new security risk.
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed.,
"Intermediate System to Intermediate System (IS-IS)
Extensions for Advertising Router Information", RFC 4971,
DOI 10.17487/RFC4971, July 2007,
<http://www.rfc-editor.org/info/rfc4971>.
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7.2. Informative References
[I-D.ietf-sfc-architecture]
Halpern, J. and C. Pignataro, "Service Function Chaining
(SFC) Architecture", draft-ietf-sfc-architecture-11 (work
in progress), July 2015.
[I-D.xu-mpls-service-chaining]
Xu, X., Bryant, S., Assarpour, H., Shah, H., Contreras,
L., and d. daniel.bernier@bell.ca, "Service Chaining using
MPLS Source Routing", draft-xu-mpls-service-chaining-00
(work in progress), October 2016.
[I-D.xu-mpls-unified-source-routing-instruction]
Xu, X., Bryant, S., Raszuk, R., Chunduri, U., Contreras,
L., Jalil, L., and H. Assarpour, "Unified Source Routing
Instruction using MPLS Label Stack", draft-xu-mpls-
unified-source-routing-instruction-00 (work in progress),
March 2017.
Authors' Addresses
Xiaohu Xu
Huawei
Email: xuxiaohu@huawei.com
Nan Wu
Huawei
Email: eric.wu@huawei.com
Himanshu Shah
Ciena
Email: hshah@ciena.com
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Luis M. Contreras
Telefonica I+D
Ronda de la Comunicacion, s/n
Sur-3 building, 3rd floor
Madrid, 28050
Spain
Email: luismiguel.contrerasmurillo@telefonica.com
URI: http://people.tid.es/LuisM.Contreras/
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