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Foundation Summary 243
Table 7-6
OSPF Network Types
Type
Comments
Point-to-point
Connects a single pair of routes over point-to-point serial links. Does not elect a
DR or BDR. Dynamically establishes a neighbor relationship.
Broadcast
Connects two or more routers over broadcast media. Elects a DR and a BDR.
Establishes adjacencies between each neighbor and the DR and BDR.
Nonbroadcast
Connects more than two routes. Requires manual configuration to establish
neighbor relationships. Elects a DR and a BDR.
Point-to-multipoint
A configuration applied to NBMA networks. Connects more than two routers.
Dynamically establishes a neighbor relationship. Does not elect a DR or BDR.
Table 7-7
IGRP Features
Feature
Comments
Scalability
Can be configured for large internetworks. Can scale up to 255 hops.
Sophisticated metric
Uses a composite metric of bandwidth, delay, reliability, load, and hop-
count.
Multiple paths
Can maintain up to four unequal paths between source and destination.
Fast response
Sends updates when route topology changes.
Table 7-8
EIGRP Characteristics
Feature
Comments
Neighbor
discovery
Routers dynamically learn about other routers on their directly attached networks.
Routers also can discover when their neighbors become unreachable or
inoperative.
Manual
summarization
By default, EIGRP summarizes at the classful boundary. EIGRP can be
configured to pass discontiguous subnets.
Redistributive
compatibility
with IGRP
Automatic redistribution when IGRP has the same autonomous system.
Supports VLSM
Allows flexibility in IP addressing.
Low use of
bandwidth
EIGRP does not send updates unless hello packets detect a change in network
topology.
87200333.book Page 243 Wednesday, August 22, 2001 2:37 PM