Network Working Group Acee Lindem (Redback Networks) Internet Draft Expiration Date: August 2004 Proposed Status: Informational File name: draft-ietf-ospf-graceful-impl-report-03.txt Mar 2004 Graceful OSPF Restart Implementation Report draft-ietf-ospf-graceful-impl-report-03.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 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 ................................. 5 12 Acknowledgments ........................................ 6 13 Author's Address ....................................... 6 Lindem [Page 1]
Internet Draft Graceful OSPF Restart Implementation Report Mar 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. Lindem [Page 2]
Internet Draft Graceful OSPF Restart Implementation Report Mar 2004 2. Implementation Experience Eight 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, and Alcatel. 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. Five successfully tested interoperability with Juniper. Juniper successfully tested interoperability with Force10 Networks. 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. Three vendors made it configurable (two defaulted it to enabled and the other disabled), another made it a compile option (shipping with strict LSA checking disabled), another didn't implement it at all, and three 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. Six vendors implemented the option of received grace LSA only applying to the adjacency on which it was received. Two 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]. Three vendors implemented extensions and five did not. It should be noted that such extensions are beyond the scope of Graceful OSPF Restart [GRACE]. Lindem [Page 3]
Internet Draft Graceful OSPF Restart Implementation Report Mar 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. Lindem [Page 4]
Internet Draft Graceful OSPF Restart Implementation Report Mar 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. 11. Informative References [VPN] Rosen, E., Rekhter, Y. "BGP/MPLS IP VPNs", draft-ietf-l3vpn-rfc2547bis-01.txt, September 2003, work in progress. Lindem [Page 5]
Internet Draft Graceful OSPF Restart Implementation Report Mar 2004 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) 13. Author's Address Acee Lindem Redback Networks 102 Carric Bend Court Cary, NC 27519 Email: acee@redback.com Lindem [Page 6]
