Cisco WS-C3550-12G Software Configuration Manual page 577

Chapter 22 Configuring IP Unicast Routing
feasible successors, but there are neighbors advertising the destination, a recomputation must occur.
This is the process whereby a new successor is determined. The amount of time it takes to recompute
the route affects the convergence time. Recomputation is processor-intensive; it is advantageous to
avoid recomputation if it is not necessary. When a topology change occurs, DUAL tests for feasible
successors. If there are feasible successors, it uses any it finds to avoid unnecessary recomputation.
The protocol-dependent modules are responsible for network layer protocol-specific tasks. An
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example is the IP EIGRP module, which is responsible for sending and receiving EIGRP packets
that are encapsulated in IP. It is also responsible for parsing EIGRP packets and informing DUAL
of the new information received. EIGRP asks DUAL to make routing decisions, but the results are
stored in the IP routing table. EIGRP is also responsible for redistributing routes learned by other
IP routing protocols.
Table 22-9
Table 22-9 Default EIGRP Configuration
Feature
Auto summary
Default-information
Default metric
Distance
EIGRP log-neighbor changes
IP authentication key-chain
IP authentication mode
IP bandwidth-percent
IP hello interval
IP hold-time
IP split-horizon
IP summary address
Metric weights
78-11194-03
shows the default EIGRP configuration.
Default Setting
Enabled. Subprefixes are summarized to the classful network
boundary when crossing classful network boundaries.
Exterior routes are accepted and default information is passed
between IGRP or EIGRP processes when doing redistribution.
Only connected routes and interface static routes can be redistributed
without a default metric. The metric includes:
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Internal distance: 90.
External distance: 170.
Disabled. No adjacency changes logged.
No authentication provided.
No authentication provided.
50 percent.
For low-speed nonbroadcast multiaccess (NBMA) networks:
60 seconds; all other networks: 5 seconds.
For low-speed NBMA networks: 180 seconds; all other networks:
15 seconds.
Enabled.
No summary aggregate addresses are predefined.
tos: 0; k1 and k3: 1; k2, k4, and k5: 0
Bandwidth: 0 or greater kbps.
Delay (tens of microseconds): 0 or any positive number that is a
multiple of 39.1 nanoseconds.
Reliability: any number between 0 and 255 (255 means
100 percent reliability).
Loading: effective bandwidth as a number between 0 and 255
(255 is 100 percent loading).
MTU: maximum transmission unit size of the route in bytes. 0 or
any positive integer.
Catalyst 3550 Multilayer Switch Software Configuration Guide
Configuring EIGRP
22-47