RIP Version 2 Protocol Analysis (RFC1721)
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2019-Feb-12
Internet Society Requests For Comment (RFCs)
As required by Routing Protocol Criteria (RFC 1264), this report documents the key features of the RIP-2 protocol and the current implementation experience. This report is a prerequisite to advancing RIP-2 on the standards track. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.
Network Working Group G. Malkin Request for Comments: 1721 Xylogics, Inc. Obsoletes: 1387 November 1994 Category: Informational
RIP Version 2 Protocol Analysis
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.
As required by Routing Protocol Criteria (RFC 1264), this report documents the key features of the RIP-2 protocol and the current implementation experience. This report is a prerequisite to advancing RIP-2 on the standards track.
The RIP-2 protocol owes much to those who participated in the RIP-2 working group. A special thanks goes to Fred Baker, for his help on the MIB, and to Jeffrey Honig, for all his comments.
1. Protocol Documents
The RIP-2 applicability statement is defined in RFC 1722 .
The RIP-2 protocol description is defined in RFC 1723 . This memo obsoletes RFC 1388, which specifies an update to the "Routing Information Protocol" RFC 1058 (STD 34).
The RIP-2 MIB description is defined in RFC 1724 . This memo obsoletes RFC 1389.
2. Key Features
While RIP-2 shares the same basic algorithms as RIP-1, it supports several new features. They are: external route tags, subnet masks, next hop addresses, and authentication.
The significant change from RFC 1388 is the removal of the domain field. There was no clear agreement as to how the field would be used, so it was determined to leave the field reserved for future expansion.
Malkin [Page 1]
RFC 1721 RIP-2 Analysis November 1994
2.1 External Route Tags
The route tag field may be used to propagate information acquired from an EGP. The definition of the contents of this field are beyond the scope of this protocol. However, it may be used, for example, to propagate an EGP AS number.
2.2 Subnet Masks
Inclusion of subnet masks was the original intent of opening the RIP protocol for improvement. Subnet mask information makes RIP more useful in a variety of environments and allows the use of variable subnet masks on the network. Subnet masks are also necessary for implementation of "classless" addressing, as the CIDR work proposes.
2.3 Next Hop Addresses
Support for next hop addresses allows for optimization of routes in an environment which uses multiple routing protocols. For example, if RIP-2 were being run on a network along with another IGP, and one router ran both protocols, then that router could indicate to the other RIP-2 routers that a better next hop than itself exists for a given destination.
One significant improvement RIP-2 offers over RIP-1, is the addition of an authentication mechanism. Essentially, it is the same extensible mechanism provided by OSPF. Currently, only a plain-text password is defined for authentication. However, more sophisticated authentication schemes can easily be incorporated as they are defined.
RIP-2 packets may be multicast instead of being broadcast....