RIP Version 2 Protocol Analysis (RFC1721)
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2000-Sep-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.
Network Working Group G. Malkin
Request for Comments: 1721 Xylogics, Inc.
Obsoletes: 1387 November 1994
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
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
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. Howev...