SFC WG C. Wu
Internet-Draft Zhejiang University
Intended status: Standards Track C. Wang
Expires: June 6, 2015 W. Meng
ZTE Corporation
B. Khasnabish
ZTE TX, Inc.
December 3, 2014
Multi-Layer OAM for Service function Chaining
draft-wang-sfc-multi-layer-oam-01
Abstract
Since there are different notions of service chain, such as fully
abstract notion named SFC, half-fully abstraction notion named SFP
and fully specific notion named RSP, and there are different
components defined in SFC architecture, it seems reasonable to define
differentiated OAM for these different service chains. This document
tries to discuss the multi-layer OAM requirements in SFC domain and
provides a multi-layer OAM solution for different service chains.
Status of this Memo
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This Internet-Draft will expire on June 6, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Convention and Terminology . . . . . . . . . . . . . . . . . . 4
3. Requirement . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Multi-layer SFC OAM architecture . . . . . . . . . . . . . . . 7
5. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Normative References . . . . . . . . . . . . . . . . . . . 11
8.2. Informative References . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
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1. Introduction
Since there are different notions of service chain, such as fully
abstract notion named SFC, half-fully abstraction notion named SFP
and fully specific notion named RSP, and there are different
components defined in SFC architecture, it seems reasonable to define
differentiated OAM for these different service chains. This document
tries to discuss the multi-layer OAM requirements in SFC domain and
provides a multi-layer OAM solution for different service chains.
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2. Convention and Terminology
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 [RFC2119].
The terms are all defined in [I-D.ietf-sfc-architecture].
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3. Requirement
In fact, besides the link layer OAM, network layer OAM, SFC service
layer OAM is requisite in SFC Domain, which may be typically
illustrated in Figure 1.
+-----------+ +---+ +---+ +---+ +---+ +---+
|Classifier |---|SF1|---|SF2|---|SF3|---|SF4|---|SF5|
+-----------+ +---+ +---+ +---+ +---+ +---+
|------------SFC Service layer OAM------------|
Figure 1: typical SFC service layer OAM
Currently, according to the latest SFC architecture, we know that
there are several components defined in the SFC architecture, such as
SN, SFF, SF,etc, and the relationship between them like this:
serveral SFs may share the same SFF, and furthermore, serveral SFFs
may share the same SN(e.g, different SFFs residented in one service
node belong to different VPNs). As a result of that, multiple RSPs,
such as RSP1(SF1--SF3--SF5) and RSP2(SF2--SF4--SF6) in Figure 2, may
not share the same transmitting path, but they may share the same
SFFs path.
+---+ +---+ +---+ +---+ +---+ +---+
|SF1| |SF2| |SF3| |SF4| |SF5| |SF6|
+---+ +---+ +---+ +---+ +---+ +---+
\ / \ / \ /
+-----------+ +----+ +----+ +----+
|Classifier |---|SFF1|-----------|SFF2|-----------|SFF3|
+-----------+ +----+ +----+ +----+
Figure 2: different RSPs share the same SFFs path
And also, multiple SFPs, such as SFP1(SFF1--SFF3--SFF5)(e.g, VPN1)
and SFP2(SFF2--SFF4--SFF6)(e.g, VPN2) in Figure 3, may not share the
same SFFs, but they may share the same SNs path.
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+----+ +----+ +----+ +----+ +----+ +----+
|SFF1| |SFF2| |SFF3| |SFF4| |SFF5| |SFF6|
+----+ +----+ +----+ +----+ +----+ +----+
\ / \ / \ /
+-----------+ +----+ +----+ +----+
|Classifier |---|SN1 |------------|SN2 |-------------|SN3 |
+-----------+ +----+ +----+ +----+
Figure 3: different SFPs share the same SNs path
As for users who want to diagnose, troubleshoot a set of RSPs which
transmit the same SFFs, or a set of SFPs which transmit the same SNs,
there is an aggregative method which can aggregate a set of RSPs or a
set of SFPs into one, then, users only need to diagnose, troubleshoot
the aggregative one, rather than the separated one by one. And also,
if users are willing to diagnose and troubleshoot one by one, once
the connectivity between different SFs is not OK, users can detect
the connectivity between different SFFs where the SFs resident
instead to narrow the failure coverage. In other words, if the
connectivity between the detected SFFs is not OK, then the
connectivity problem is located. if the connectivity betwwen the
detected SFFs is OK, then the connectivity problem should be between
the detected SFs and the detected SFFs, which can help to improve the
efficiency of target location remarkably. Obviously, they can be
diagnosed, troubleshooted one by one or aggregatively according to
preferance.
As follow, this document tries to provide an architecture and a
solution for differentiated layer OAM for this requirement.
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4. Multi-layer SFC OAM architecture
Figure 4 is a possible architecture for multi-layer SFC OAM. In this
figure, it tries to figure out three possible layers. The layer 1 is
the most aggregative layer for service chain. It stretches the path
which SNs go through according to the sets of RSPs or SFPs or SFCs.
The layer 2 is the medium aggregative layer for service chain. It
outlines the path which SFFs go though according to the sets of RSPs
or SFPs or SFCs. The layer 3 is the specific path for service chain.
It is exactly the path which SFs go though according to the sets of
RSPs or SFPs or SFCs.
+---+ +---+ +----+ +----+ +-----+ +-----+ +------+ +------+
|SF1|..|SFn| |SF1'|..|SFn'| |SF1''|..|SFn''| |SF1'''|..|SFn'''|
+---+ +---+ +----+ +----+ +-----+ +-----+ +------+ +------+
\ / \ / | \ / \ / |
+----+ +----+ | +-----+ +-----+ |
|SFF1| ... |SFFn| | |SFF1'| ... |SFFn'| |
+----+ +----+ | +-----+ +-----+ |
\ / | | \ / | |
+-----------+ +-------+ | | +-------+ | |
|Classifier |------| SN1 |---|------|------------------| SNn | | |
+-----------+ +-------+ | | +-------+ | |
| | | | | |
|------|------|-Layer 1---------------| | |
| | | |
|------|--------Layer 2-----------------| |
| |
|--------------Layer 3-----------------|
| |
Figure 4: a possible architecture for multi-layer SFC OAM
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5. Solution
If anyone is interested in this requirement, I will update the
solution in the next version.
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6. Security Considerations
It will be considered in a future revision.
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7. IANA Considerations
It will be considered in a future revision.
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8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. Informative References
[I-D.boucadair-sfc-requirements]
Boucadair, M., Jacquenet, C., Jiang, Y., Parker, R.,
Pignataro, C., and K. Kengo, "Requirements for Service
Function Chaining (SFC)",
draft-boucadair-sfc-requirements-05 (work in progress),
July 2014.
[I-D.ietf-sfc-architecture]
Halpern, J. and C. Pignataro, "Service Function Chaining
(SFC) Architecture", draft-ietf-sfc-architecture-02 (work
in progress), September 2014.
[I-D.ietf-sfc-problem-statement]
Quinn, P. and T. Nadeau, "Service Function Chaining
Problem Statement", draft-ietf-sfc-problem-statement-10
(work in progress), August 2014.
[I-D.krishnan-sfc-oam-req-framework]
Krishnan, R., Ghanwani, A., Gutierrez, P., Lopez, D.,
Halpern, J., Kini, S., and A. Reid, "SFC OAM Requirements
and Framework", draft-krishnan-sfc-oam-req-framework-00
(work in progress), July 2014.
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Authors' Addresses
Wu Chunming
Zhejiang University
No.38 Zheda Road, Xihu District
Hangzhou
China
Email: wuchunming@zju.edu.cn
Cui Wang
ZTE Corporation
No.50 Software Avenue, Yuhuatai District
Nanjing
China
Email: wang.cui1@zte.com.cn
Wei Meng
ZTE Corporation
No.50 Software Avenue, Yuhuatai District
Nanjing
China
Email: meng.wei2@zte.com.cn,vally.meng@gmail.com
Bhumip Khasnabish
ZTE TX, Inc.
55 Madison Avenue, Suite 160
Morristown, New Jersey 07960
USA
Email: bhumip.khasnabish@ztetx.com
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