Understanding the network.pdf - Back to Home

As a rule, static routes have a role in every routing environment. They
should, however, be used as part of a sane routing strategy. Chapter
10 looks at different ways to use static routing in enterprise network
environments.
TCP/IP Interior Gateway Protocols
At this point, you should have a solid understanding of how IP
datagrams are routed, what the basic elements of dynamic routing
protocols are, and why they are necessary. This section provides you
with an overview of how RIP, IGRP, EIGRP, and OSPF work.
Implementation and configuration of these protocols are covered in
Chapter 10.
Routing Information Protocol, v1 and v2
RIP has the largest support base of any of the dynamic routing
protocols. Almost every Layer 3 network device on the market
supports at least one version or both versions of RIP. RIP is also
available on most of the popular operating systems (UNIX and
Windows NT), giving end-stations the capability to support multiple
network gateways. RIP's universal support and easy setup make it
very common in small, static point-to-point and redundant path LAN
networks.
RIP comes in two flavors: v1 and v2. RIPv1 is a basic single metric
distance vector protocol. RIPv1 provides support only for classful
addressing and is limited to a network radius of 15 hops (Layer 3
address segments) from the first router to the last.
RIPv2 fixes the security holes that existed in RIPv1, and provides
support for routing authentication, route summarization, CIDR, and
VLSM support. Both RIPv1 and RIPv2 use the same message format.
However, RIPv1 cannot read RIPv2 messages, so if both versions of
the protocols are running, compatibility options need to be enabled.
RIPv1 uses UDP (User Datagram Protocol) broadcasts (source and
destination port 520) to transport messages. RIPv2 uses the multicast
address 224.0.0.9 (also to port 520) to transport messages.
NOTE