RIPng Protocol Applicability Statement (RFC2081)
Original Publication Date: 1997-Jan-01
Included in the Prior Art Database: 2000-Sep-13
Internet Society Requests For Comment (RFCs)
As required by Routing Protocol Criteria (RFC 1264), this report defines the applicability of the RIPng protocol within the Internet. This report is a prerequisite to advancing RIPng on the standards track.
Network Working Group G. Malkin
Request for Comments: 2081 Xylogics
Category: Informational January 1997
RIPng Protocol Applicability Statement
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
defines the applicability of the RIPng protocol within the Internet.
This report is a prerequisite to advancing RIPng on the standards
1. Protocol Documents
The RIPng protocol description is defined in RFC 2080.
This report describes how RIPng may be useful within the new IPv6
Internet. In essence, the environments in which RIPng is the IGP of
choice is comparable to the environments in which RIP-2 (RFC 1723) is
used in the IPv4 Internet. It is important to remember that RIPng is
a simple extrapolation of RIP-2; RIPng has nothing conceptually new.
Thus, the operational aspects of distance-vector routing protocols,
and RIP-2 in particular, within an autonomous system are well
It should be noted that RIPng is not intended to be a substitute for
OSPFng in large autonomous systems; the restrictions on AS diameter
and complexity which applied to RIP-2 also apply to RIPng. Rather,
RIPng allows the smaller, simpler, distance-vector protocol to be
used in environments which require authentication or the use of
variable length subnet masks, but are not of a size or complexity
which require the use of the larger, more complex, link-state
The remainder of this report describes how each of the features of
RIPng is useful within IPv6.
A goal in developing RIPng was to make the minimum necessary change
to RIP-2 to produce RIPng. In essence, the IPv4 address was expanded
into an IPv6 address, the IPv4 subnet mask was replaced with an IPv6
prefix length, the next-hop field was eliminated but the
functionality has been preserved, and authentication was removed.
The route tag field has been preserved. The maximum diameter of the
network (the maximum metric value) is 15; 16 still means infinity
The basic RIP header is unchanged. However, the size of a routing
packet is no longer arbitrarily limited. Because routing updates are
never forwarded, the routing packet size is now determined by the
physical media and the sizes of the headers which precede the routing
data (i.e., media MTU minus the combined header lengths). The number
routes which may be included in a routing update is the routing data
length divided by the size of a routing entry.
The address field of a routing entry is 128 bits in length, expanded
from the 32 bits available in RIP-2. This allows the RIP entry...