38-37
Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
Chapter38 Configuring IP Unicast Routing
Configuring EIGRP
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
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.
These sections contain this configuration information:
Default EIGRP Configuration, page38-37
Configuring Basic EIGRP Parameters, page38-40
Configuring EIGRP Interfaces, page38-41
Configuring EIGRP Route Authentication, page38-41
Configuring EIGRP Stub Routing, page38-42
Monitoring and Maintaining EIGRP, page38-44
Note To enable EIGRP, the stack master must be running the IP services image.
Default EIGRP Configuration
Table38-7 shows the default EIGRP configuration.
Table38-7 Default EIGRP Configuration
Feature Default Setting
Auto summary Disabled. Subprefixes are not summarized to the classful network
boundary when crossing classful network boundaries.
Default-information Exterior routes are accepted and default information is passed
between EIGRP processes when doing redistribution.
Default metric Only co nnected routes and interface static routes can be redistributed
without a default metric. The metric includes:
Bandwidth: 0 or greater kb/s.
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.