RFC 1721 (rfc1721) - Page 2 of 4
RIP Version 2 Protocol Analysis
Alternative Format: Original Text Document
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.
2.4 Authentication
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.
2.5 Multicasting
RIP-2 packets may be multicast instead of being broadcast. The use
of an IP multicast address reduces the load on hosts which do not
support routing protocols. It also allows RIP-2 routers to share
information which RIP-1 routers cannot hear. This is useful since a
RIP-1 router may misinterpret route information because it cannot
apply the supplied subnet mask.
3. RIP-2 MIB
The MIB for RIP-2 allows for monitoring and control of RIP's
operation within the router. In addition to global and per-interface
counters and controls, there are per-peer counters which provide the
status of RIP-2 "neighbors".
Malkin