spring N. Kumar
Internet-Draft C. Pignataro
Intended status: Informational N. Akiya
Expires: January 2, 2015 Cisco Systems, Inc.
R. Geib
Deutsche Telekom
G. Mirsky
Ericsson
July 1, 2014
OAM Requirements for Segment Routing Network
draft-kumar-spring-sr-oam-requirement-01
Abstract
This document describes a list of functional requirement for OAM in
Segment Routing (SR) based network.
Status of This Memo
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This Internet-Draft will expire on January 2, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements notation . . . . . . . . . . . . . . . . . . . . 2
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
4. Detailed Requirement list . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 4
8. Contributing Authors . . . . . . . . . . . . . . . . . . . . 4
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
9.1. Normative References . . . . . . . . . . . . . . . . . . 5
9.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
[I-D.filsfils-spring-segment-routing] introduces and explains Segment
Routing architecture that leverages source routing and tunneling
standards which can be applied directly to MPLS dataplane with no
changes on forwarding plane and on IPv6 dataplane with new Routing
Extension Header.
This document list the OAM requirements for Segment Routing based
network which can further be used to produce OAM tools, either
through enhancing existing OAM tools or constructing new OAM tools,
for path liveliness and service validation.
2. Requirements notation
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].
3. Terminology
SR OAM Packet: OAM probe originated and processed within SR domain(s)
ECMP: Equal Cost Multipath
SR: Segment Routing
UCMP: Unequal Cost Multipath
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Initiator: Centralized OAM initiator or PMS as referred in
[I-D.geib-spring-oam-usecase]
4. Detailed Requirement list
This section list the OAM requirement for Segment Routing based
network. The below listed requirement MUST be supported with both
MPLS and IPv6 dataplane:
REQ#1: SR OAM MUST support both On-demand and Continuous OAM
functionality.
REQ#2: The SR OAM packet MUST follow exactly the same path as
dataplane traffic.
REQ#3: The SR OAM packet MUST have the ability to discover and
exercise equal cost multipath (ECMP) paths.
REQ#4: The SR OAM packet MUST have the ability to discover and
exercise unequal cost multipath (UCMP) paths.
REQ#5: The SR OAM packet MUST have ability to exercise any
available paths, not just best path available.
REQ#6: The forwarding semantic of adjacency Segment ID raises a
need for additional consideration to detect any failure in
forwarding to the right adjacency. SR OAM MUST have the
ability to detect any failure in Node SID and adjacency
segment based forwarding.
REQ#7: SR OAM MUST have the ability to be initialized from an
arbitrary node to perform connectivity verification and
continuity check to any other node within SR domain.
REQ#8: In case of any failure with continuity check, SR OAM SHOULD
support rapid Connectivity Fault localization to isolate the
node on which the failure occurs.
REQ#9: SR OAM SHOULD also have the ability to be initialized from a
centralized controller.
REQ#10: When SR OAM is initialized from centralized controller, it
MUST have the ability to alert any edge node in SR domain
about the corresponding path or service failure. The node
on receiving the alert MAY take a local protection action or
pop an informational message.
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REQ#11: When SR OAM is initialized from centralized controller, it
SHOULD support node redundancy. If primary Initiator fails,
secondary one MUST take over the responsibility without
having any impact on customer traffic.
REQ#12: SR OAM MUST have the ability to measure Packet loss, Packet
Delay or Delay variation.
REQ#13: When a new path is instantiated, SR OAM SHOULD allow path
verification without noticeable delay.
REQ#14: The above listed requirements SHOULD be supported without
any scalability limitation imposed and SHOULD be extensible
to accommodate any new SR functionality.
REQ#15: SR OAM SHOULD NOT create or maintain per path state entry in
any other nodes other than the Initiator.
REQ#16: When traffic engineering is initiated by centralized
controller device, and when SR OAM is performed by
individual nodes, there MUST be a mechanism to communicate
failure to centralized controller device.
REQ#17: When service instruction is present in SR OAM packet header,
there MUST be a method to disallow applying the service to
the OAM packet to handle cases where that may result in
unintended corruption of the OAM packet.
5. IANA Considerations
This document does not propose any IANA consideration.
6. Security Considerations
This document list the OAM requirement for Segment Routing network
and does not raise any security considerations.
7. Acknowledgement
The authors would like to thank Stefano Previdi for his review.
8. Contributing Authors
Sriganesh Kini
Ericsson
Email: sriganesh.kini@ericsson.com
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9. References
9.1. Normative References
[I-D.filsfils-spring-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-spring-
segment-routing-04 (work in progress), July 2014.
[I-D.geib-spring-oam-usecase]
Geib, R., Filsfils, C., Pignataro, C., and N. Kumar, "Use
case for a scalable and topology aware MPLS data plane
monitoring system", draft-geib-spring-oam-usecase-02 (work
in progress), July 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
9.2. Informative References
[RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379,
February 2006.
[RFC6291] Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
D., and S. Mansfield, "Guidelines for the Use of the "OAM"
Acronym in the IETF", BCP 161, RFC 6291, June 2011.
[RFC6424] Bahadur, N., Kompella, K., and G. Swallow, "Mechanism for
Performing Label Switched Path Ping (LSP Ping) over MPLS
Tunnels", RFC 6424, November 2011.
[RFC6425] Saxena, S., Swallow, G., Ali, Z., Farrel, A., Yasukawa,
S., and T. Nadeau, "Detecting Data-Plane Failures in
Point-to-Multipoint MPLS - Extensions to LSP Ping", RFC
6425, November 2011.
Authors' Addresses
Nagendra Kumar
Cisco Systems, Inc.
7200 Kit Creek Road
Research Triangle Park, NC 27709
US
Email: naikumar@cisco.com
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Carlos Pignataro
Cisco Systems, Inc.
7200 Kit Creek Road
Research Triangle Park, NC 27709-4987
US
Email: cpignata@cisco.com
Nobo Akiya
Cisco Systems, Inc.
2000 Innovation Drive
Kanata, ON K2K 3E8
Canada
Email: nobo@cisco.com
Ruediger Geib
Deutsche Telekom
Heinrich Hertz Str. 3-7
Darmstadt 64295
Germany
Email: Ruediger.Geib@telekom.de
Greg Mirsky
Ericsson
Email: gregory.mirsky@ericsson.com
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