background image
Troubleshooting RIP
335
These types and codes allow ICMP to communicate network status and
information among hosts and routers. ICMP is a very useful protocol in the
troubleshooting arsenal.
Troubleshooting RIP
R
IP was first designed for Xerox. The protocol, known as routed, was
later used in UNIX. Thereafter, RIP was implemented as a TCP/IP routing
protocol. RIP is used by most versions of Novell NetWare for routing. Other
protocols have been derived from RIP.
RIP1 and RIP2
The original version of RIP (RIP1) had several limitations that restricted its
use and scalability. Problems such as the frequent routing updates and lim-
ited hop-count needed to be overcome.
RIP uses UDP broadcasts to flood route updates. Every router floods the
network with its update. RIP also features split horizon and poison reverse
updates to prevent routing loops. RIP updates every 30 seconds and has a
hop-count limit of 16 hops.
RIP2 functions in much the same way as RIP1, but with a few enhance-
ments. RIP2 supports classless routing (CIDR), route summarization, and
variable length subnet masks (VLSM).
show Commands
The show commands that are useful for troubleshooting RIP1 and RIP2 are
listed in Table 6.4.
T A B L E 6 . 4
RIP-Related show Commands
Command
Description
show ip route rip
Displays the RIP route table
show ip route
Displays the IP route table
show ip interface
Displays IP interface configuration
show running-config
Displays the running configuration
Copyright ©2000 SYBEX , Inc., Alameda, CA
www.sybex.com