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420 Chapter 6: Routing
Table 6-26 lists the features for summarization of the interior IP routing protocols.
Table 6-27 lists the similarities and differences between IP RIP and IPX RIP.
Table 6-28 summarizes the key concepts behind separate and integrated multiprotocol routing.
Uses authentication
Both clear text (RFC-defined) and MD5 encryption (Cisco-
added feature) can be used to authenticate the source of a
routing update.
Uses next-hop router IP address in
routing update
A router can advertise a route but direct any listeners to a
different router on that same subnet. This is done only when
the other router has a better route.
Uses external route tags
RIP can pass information about routes learned from an
external source and can be redistributed into RIP.
Provides multicast routing updates
Instead of sending updates to 255.255.255.255, the
destination IP address is 224.0.0.9, an IP multicast address.
This reduces the amount of processing required on non-
RIP-speaking hosts on a common subnet.
Table 6-26
Route Aggregation Comparison of Subnet Numbers
Routing Protocol
Auto Summary
Enabled?
Auto Summary
Disabled?
Route
Aggregation?
RIP Version 1
Yes, by default
Not allowed
No
IGRP
Yes, by default
Not allowed
No
RIP Version 2
Yes, by default
Allowed via configuration
No
EIGRP
Yes, by default
Allowed via configuration
Yes
OSPF
No, but can do equivalent
with aggregation
Yes
Yes
Table 6-27
RIP for IPX and IP Compared
Novell RIP
IP RIP
Uses distance vector
Uses distance vector
Is based on XNS RIP
Is based on XNS RIP
Uses 60-second update timer (default)
Uses 30-second update timer (default)
Uses timer ticks as primary metric and hop count
as secondary metric
Uses hop count as only metric
Table 6-25
RIP-2 Features (Continued)
Feature
Description
ch06.fm Page 420 Monday, March 20, 2000 5:11 PM