A BGP/IDRP Route Server alternative to a full mesh routing
RFC 1863
Document | Type |
RFC - Historic
(October 1995; No errata)
Obsoleted by RFC 4223
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Last updated | 2013-03-02 | ||
Stream | IETF | ||
Formats | plain text pdf htmlized bibtex | ||
Stream | WG state | WG Document | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 1863 (Historic) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group D. Haskin Request For Comments: 1863 Bay Networks, Inc. Category: Experimental October 1995 A BGP/IDRP Route Server alternative to a full mesh routing Status of this Memo This memo defines an Experimental Protocol for the Internet community. This memo does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited. Abstract This document describes the use and detailed design of Route Servers for dissemination of routing information among BGP/IDRP speaking routers. The intention of the proposed technique is to reduce overhead and management complexity of maintaining numerous direct BGP/IDRP sessions which otherwise might be required or desired among routers within a single routing domain as well as among routers in different domains that are connected to a common switched fabric (e.g. an ATM cloud). 1. Overview Current deployments of Exterior Routing protocols, such as the Border Gateway Protocol [BGP4] and the adaptation of the ISO Inter-Domain Routing Protocol [IDRP], require that all BGP/IDRP routers, which participate in inter-domain routing (border routers) and belong to the same routing domain, establish a full mesh connectivity with each other for purpose of exchanging routing information acquired from other routing domains. In large routing domains the number of intra- domain connections that needs to be maintained by each border route can be significant. In addition, it may be desired for a border router to establish routing sessions with all border routers in other domains which are reachable via a shared communication media. We refer to routers that are directly reachable via a shared media as adjacent routers. Such direct peering allows a router to acquire "first hand" information about destinations which are directly reachable through adjacent routers and select the optimum direct paths to these destinations. Establishment of BGP/IDRP sessions among all adjacent border routers would result in a full mesh routing connectivity. Unfortunately for Haskin Experimental [Page 1] RFC 1863 A BGP/IDRP Route Server October 1995 a switched media as ATM, SMDS or Frame Relay network which may inter-connect a large number of routers, due to the number of connections that would be needed to maintain a full mesh direct peering between the routers, makes this approach impractical. In order to alleviate the "full mesh" problem, this paper proposes to use IDRP/BGP Route Servers which would relay external routes with all of their attributes between client routers. The clients would maintain IDRP/BGP sessions only with the assigned route servers (sessions with more than one server would be needed if redundancy is desired). All routes that are received from a client router would be propagated to other clients by the Route Server. Since all external routes and their attributes are relayed unmodified between the client routers, the client routers would acquire the same routing information as they would via direct peering. We refer to such arrangement as virtual peering. Virtual peering allows client routers independently apply selection criteria to the acquired external routes according to their local policies as they would if a direct peering were established. The routing approach described in this paper assumes that border routers possess a mechanism to resolve the media access address of the next hop router for any route acquired from a virtual peer. It is fair to note that the approach presented in this paper only reduces the number of routing connection each border router needs to maintain. It does not reduce the volume of routing information that needs to maintained at each border router. Besides addressing the "full mesh" problems, the proposal attempts to achieve the following goals: - to minimize BGP/IDRP changes that need to be implemented in client routers in order to inter-operate with route servers; - to provide for redundancy of distribution of routing information to route server clients; - to minimize the amount of routing updates that have to be sent to route server clients; - to provide load distribution between route servers; - to avoid an excessive complexity of the interactions between Route Servers themselves. Haskin Experimental [Page 2] RFC 1863 A BGP/IDRP Route Server October 1995 2. Terms And Acronyms The following terms and acronyms are used in this paper: Routing Domain - a collection of routers with the same set ofShow full document text