Graceful OSPF Restart Implementation Report
draft-ietf-ospf-graceful-impl-report-05
The information below is for an old version of the document that is already published as an RFC.
| Document | Type | RFC Internet-Draft (ospf WG) | |
|---|---|---|---|
| Author | Acee Lindem | ||
| Last updated | 2015-10-14 (Latest revision 2004-04-28) | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text htmlized pdfized bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | (None) | ||
| IESG | IESG state | RFC 4167 (Informational) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | Alex D. Zinin | ||
| Send notices to | rohit@utstar.com |
draft-ietf-ospf-graceful-impl-report-05
Network Working Group Acee Lindem (Redback Networks)
Internet Draft
Expiration Date: October 2004 Proposed Status: Informational
File name: draft-ietf-ospf-graceful-impl-report-05.txt May 2004
Graceful OSPF Restart Implementation Report
draft-ietf-ospf-graceful-impl-report-05.txt
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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Abstract
Graceful OSPF Restart as specified in RFC 3623 provides a mechanism
whereby an OSPF router can stay on the forwarding path even as its
OSPF software is restarted. This document provides an
implementation report for this extension to the base OSPF protocol.
Table of Contents
1 Overview ............................................... 2
2 Implementation Experience .............................. 3
2.1 Implementation Differences ............................. 3
3 MIB Reference .......................................... 4
4 Authentication Mechanisms .............................. 4
5 List of Implementations ................................ 4
6 Test Scenarios ......................................... 4
7 Operational Experience ................................. 4
8 Security Considerations ................................ 5
9 Intellectual Property .................................. 5
10 Normative References ................................... 5
11 Informative References ................................. 6
12 Acknowledgments ........................................ 6
13 Author's Address ....................................... 6
Lindem [Page 1]
Internet Draft Graceful OSPF Restart Implementation Report May 2004
1. Overview
Today many Internet routers implement a separation of control and
forwarding functions. Certain processors are dedicated to control
and management tasks such as OSPF routing, while other processors
perform the data forwarding tasks. This separation creates the
possibility of maintaining a router's data forwarding capability
while the router's control software is restarted/reloaded. For the
OSPF protocol [1], this protocol mechanisms necessary to accomplish
this are described in Graceful OSPF Restart [GRACE].
This document satisfies the RFC 1264 [CRITERIA] requirement for a
report on implementation experience for Graceful OSPF Restart.
Section 2 of this document contains the results of an
implementation survey. It also documents implementation differences
between the vendors responding to the survey. Section 3 contains a
MIB reference. Sections 4 provide an authentication reference.
Section 5 simply refers to the implementations listed in section 2.
Section 6 includes a minimal set of test scenarios. Finally,
section 7 includes a disclaimer with respect to operational
experience.
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Internet Draft Graceful OSPF Restart Implementation Report May 2004
2. Implementation Experience
Eleven vendors have implemented graceful OSPF and have completed
the implementation survey. These include Redback, Juniper, Motorola
Computer Group (formerly Netplane Systems), Mahi Networks,
Nexthop technologies, Force10 Networks, Procket, Alcatel, Laurel
Networks, DCL (Data Connection Limited), and Ericsson. All have
implemented restart from the perspective of both a restarting
and helper router. All but one vendor implemented both planned
and unplanned restart. All implementations are original. Seven
successfully tested interoperability with Juniper. Juniper
successfully tested interoperability with Force10 Networks. One
vendor tested with John Moy's GNU Public License implementation
[OSPFD]. Two vendors hadn't tested interoperability at the time of
the survey.
2.1 Implementation Differences
The first difference was whether or not strict LSA checking was
implemented and, if so, whether it was configurable. In the context
of graceful OSPF restart, strict LSA checking indicates whether or
not a changed LSA will result in termination of graceful restart
by a helping router. Four vendors made it configurable (three
defaulted it to enabled and one disabled), another made it
a compile option (shipping with strict LSA checking disabled),
another didn't implement it at all, and five implemented strict
LSA checking with no configuration option to disable it.
The second was whether a received grace LSA would be taken to apply
only to the adjacency on which it was received or all adjacencies
with the restarting router. This is a rather subtle difference
since it only applies to helping and restarting routers with more
than one full adjacency at the time or restart. Eight vendors
implemented the option of received grace LSA only applying to the
adjacency on which it was received. Three vendors applied the grace
LSA to all adjacencies with the grace LSA originator (i.e., the
restarting router).
The final difference was in whether or not additional extensions
were implemented to accommodate other features such as protocol
redistribution or interaction with MPLS VPNs [VPN]. Five vendors
implemented extensions and six did not. It should be noted that
such extensions are beyond the scope of Graceful OSPF
Restart [GRACE].
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Internet Draft Graceful OSPF Restart Implementation Report May 2004
3. MIB Reference
MIB objects for the Graceful OSPF Restart have been added to the
OSPF Version 2 Management Information Base [OSPFMIB]. Additions
include:
- Objects ospfRestartSupport, ospfRestartInterval, ospfRestartAge,
ospfRestartExitReason, and ospfRestartStrictLsaChecking to
ospfGeneralGroup.
- Objects ospfNbrRestartHelperStatus, ospfNbrRestartHelperAge,
and ospfNbrRestartHelperExitReason to ospfNbrEntry.
- Objects ospfVirtNbrRestartHelperStatus,
ospfVirtNbrRestartHelperAge, and
ospfVirtNbrRestartHelperExitReason to ospfVirtNbrEntry.
4. Authentication Mechanisms
The authentication mechanisms are the same as those implemented
by the base OSPF protocol [OSPF].
5. List of Implementations
Refer to section 2.
6. Test Scenarios
A router implementing graceful restart should test, at a minimum,
the following scenarios as both a restarting and helping
router. For all scenarios, monitoring data plane traffic may be
used to assure the restart is non-disruptive:
1. Operation over a broadcast network.
2. Operation over a P2P network.
3. Operation over a virtual link.
4. Operation using OSPF MD5 authentication.
5. Early graceful restart termination when an LSA consistency
is detected.
6. Early graceful restart termination when a flooded LSA
changes (if implemented).
7. Operational Experience
Since the feature is configurable it is difficult to evaluate
operational experience at this juncture. However, service providers
have tested and evaluated the feature.
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Internet Draft Graceful OSPF Restart Implementation Report May 2004
8. Security Considerations
This document does not address any security issues other a reference
to the RFC 2328 [OSPF]. Security considerations for the OSPF protocol
are included in RFC2328 [OSPF]. Security considerations for Graceful
OSPF Restart are included in [GRACE].
9. Intellectual Property
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
10. Normative References
[OSPF] Moy, J., "OSPF Version 2", RFC 2328, April 1998.
[GRACE] Moy, J., Pillay-Esnault, P., Lindem, A.,
"Graceful OSPF Restart", RFC 3623, July 2003.
[OSPFMIB] Joyal, D., et al, "OSPF Version 2 Management Information
Base", draft-ietf-ospf-mib-update-08.txt, December 2003,
work in progress.
[CRITERIA] Hinden, R., "Routing Protocol Criteria", RFC 1264,
October 1991.
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Internet Draft Graceful OSPF Restart Implementation Report May 2004
11. Informative References
[VPN] Rosen, E., Rekhter, Y. "BGP/MPLS IP VPNs",
draft-ietf-l3vpn-rfc2547bis-01.txt,
September 2003, work in progress.
[OSPFD] Moy, J., "OSPF Complete Implementation",
Addison-Wesley, 1991, ISBN 0-201-30966-1
12. Acknowledgments
The author wishes to acknowledge the individuals/vendors who have
completed the implementation survey.
- Anand Oswal (Redback Networks)
- Padma Pillay-Esnault (Juniper Networks)
- Vishwas Manral (Motorola Computer Group, formerly Netplane
System).
- Sriganesh Kini (Mahi Networks)
- Jason Chen (Force10 Networks)
- Daniel Gryniewicz (NextHop Technologies)
- Hasmit Grover (Procket Networks)
- Pramoda Nallur (Alcatel)
- Ardas Cilingiroglu (Laurel Networks)
- Philip Crocker (Data Connection Limited)
- Le-Vinh Hoang (Ericsson)
13. Author's Address
Acee Lindem
Redback Networks
102 Carric Bend Court
Cary, NC 27519
Email: acee@redback.com
Lindem [Page 6]