RFC 1992 (rfc1992) - Page 1 of 27

The Nimrod Routing Architecture

Network Working Group                                      I. Castineyra
Request for Comments: 1992                                           BBN
Category: Informational                                       N. Chiappa
                                                           M. Steenstrup
                                                                     BBN
                                                             August 1996


                    The Nimrod Routing Architecture

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   We present a scalable internetwork routing architecture, called
   Nimrod.  The Nimrod architecture is designed to accommodate a dynamic
   internetwork of arbitrary size with heterogeneous service
   requirements and restrictions and to admit incremental deployment
   throughout an internetwork.  The key to Nimrod's scalability is its
   ability to represent and manipulate routing-related information at
   multiple levels of abstraction.

Table of Contents

   1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 2
   2. Overview of Nimrod . . . . . . . . . . . . . . . . . . . . . . . 3
     2.1 Constraints of the Internetworking Environment  . . . . . . . 3
     2.2 The Basic Routing Functions . . . . . . . . . . . . . . . . . 5
     2.3 Scalability Features  . . . . . . . . . . . . . . . . . . . . 6
       2.3.1 Clustering and Abstraction  . . . . . . . . . . . . . . . 6
       2.3.2 Restricting Information Distribution  . . . . . . . . . . 7
       2.3.3 Local Selection of Feasible Routes  . . . . . . . . . . . 8
       2.3.4 Caching . . . . . . . . . . . . . . . . . . . . . . . . . 8
       2.3.5 Limiting Forwarding Information . . . . . . . . . . . . . 8
   3. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . 8
     3.1 Endpoints   . . . . . . . . . . . . . . . . . . . . . . . . . 9
     3.2 Nodes and Adjacencies . . . . . . . . . . . . . . . . . . . . 9
     3.3 Maps  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
       3.3.1 Connectivity Specifications  . . . . . . . . . . . . . . 10
     3.4  Locators  . . . . . . . . . . . . . . . . . . . . . . . . . 10
     3.5 Node Attributes  . . . . . . . . . . . . . . . . . . . . . . 11
       3.5.1 Adjacencies  . . . . . . . . . . . . . . . . . . . . . . 11
       3.5.2 Internal Maps  . . . . . . . . . . . . . . . . . . . . . 11
       3.5.3 Transit Connectivity . . . . . . . . . . . . . . . . . . 12



Castineyra, et. al.          Informational