Network Working Group                          Internet Architecture Board
Request for Comments: 1370                             Lyman Chapin, Chair
                                                             October 1992


                   Applicability Statement for OSPF

Status of this Memo

  This memo is an IAB standards track Applicability Statement for the
  Internet community, and requests discussion and suggestions for
  improvements.  Please refer to the current edition of the "IAB
  Official Protocol Standards" for the standardization state and status
  of this specification.  Distribution of this memo is unlimited.

1. INTRODUCTION

  Users and vendors have expressed a strong need for IP routers from
  different vendors that can interoperate using a common Interior
  Gateway Protocol (IGP).  There is therefore an urgent requirement for
  a high-functionality non-proprietary 'open' IGP that will be
  ubiquitously available from all IP router vendors.

  The Open Shortest Path First (OSPF) routing protocol [1] was
  developed by the IETF to fill this need.  This Applicability
  Statement specifies the circumstances under which OSPF must be
  implemented by router vendors.  The history of OSPF development and
  the reasoning behind this Applicability Statement will be found in
  [5].

  This Applicability Statement places a requirement on vendors claiming
  conformance to this standard, in order to assure that users will have
  the option of deploying OSPF when they need a multivendor,
  interoperable IGP in their environment.  Users are of course free to
  use whatever routing protocol best meets their requirements.

2.  APPLICABILITY OF OSPF

  An IP router that implements any routing protocol (other than static
  routes) is required to implement OSPF [1] and the OSPF MIB [2].
  Within OSPF, implementation of all features except TOS (Type-of-
  Service) routing is required; implementation of TOS routing is
  recommended.

  This requirement does not prevent a router from implementing other
  routing protocols in addition to OSPF.  Complete and definitive
  requirements on all aspects of an IP router will be found in a
  forthcoming Applicability Statement: "Requirements for IP Routers"



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RFC 1370             Applicability Statement: OSPF          October 1992


  [4], currently in preparation in the IETF.  "Requirements for IP
  Routers", when it becomes a Standard, will take precedence if its
  requirements for OSPF should conflict with this present RFC.

  It should be noted that OSPF is intended for use by routers for
  exchanging dynamic routing information, and not for use by hosts.  As
  discussed in Section 3.3.1.4 of STD-2, "Requirements for Internet
  Hosts -- Communication Layers" [3], 'wiretapping' of routing
  protocols by hosts is not recommended.  Recommended mechanisms for a
  host to use for discovering local routers and detecting dead routers
  will be found in [3].  In particular, the ICMP Router Discovery
  messages, under development, will provide a standard way for a host
  to learn the addresses of local routers [6].

3.  REFERENCES

  [1] Moy, J., "OSPF Version 2", RFC 1247, Proteon, Inc., July 1991.

  [2] Baker, F., and R. Coltun, "OSPF Version 2 Management Information
      Base", RFC 1253, ACC, Computer Science Center, August 1991.

  [3] Braden, R., Editor, "Requirements for Internet Hosts --
      Communication Layers", IETF, STD 3, RFC 1122, October 1989.

  [4] Almquist, P., Editor, "Requirements for IP Routers", Work in
      Preparation, IETF.

  [5] Gross, P., Editor, "Choosing a "Common IGP" for the IP Internet
      (The IESG's Recommendation to the IAB)", RFC 1371, IESG, October
      1992.

  [6] Deering, S., Editor, "ICMP Router Discovery Messages", RFC 1256,
      Xerox PARC, September 1991.

Security Considerations

  Security issues are not discussed in this memo.

Author's Address

  A. Lyman Chapin
  BBN Communications Corporation
  150 Cambridge Park Drive
  Cambridge, MA  02140

  Phone: 617-873-3133
  Fax:   617-873-4086
  Email: [email protected]



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