Disabling automatic route summarization – Cisco ASA 5505 User Manual

Page 522

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Cisco ASA 5500 Series Configuration Guide using the CLI

Chapter 27 Configuring EIGRP

Customizing EIGRP

Both the hello interval and the advertised hold time are configured on a per-interface basis. We
recommend setting the hold time to be at minimum three times the hello interval.

To configure the hello interval and advertised hold time, perform the following steps:

Detailed Steps

Disabling Automatic Route Summarization

Automatic route summarization is enabled by default. The EIGRP routing process summarizes on
network number boundaries. This can cause routing problems if you have noncontiguous networks.

For example, if you have a router with the networks 192.168.1.0, 192.168.2.0, and 192.168.3.0
connected to it, and those networks all participate in EIGRP, the EIGRP routing process creates the
summary address 192.168.0.0 for those routes. If an additional router is added to the network with the
networks 192.168.10.0 and 192.168.11.0, and those networks participate in EIGRP, they will also be
summarized as 192.168.0.0. To prevent the possibility of traffic being routed to the wrong location, you
should disable automatic route summarization on the routers creating the conflicting summary
addresses.

To disable automatic route summarization, enter the following commands:

Command

Purpose

Step 1

interface

phy_if

Example:

hostname(config)# interface phy_if

Enters interface configuration mode for the interface on which
you are configuring the hello interval or advertised hold time.

Step 2

hello-interval eigrp

as-num seconds

Example:

hostname(config)# hello-interval eigrp 2

60

Changes the hello interval.

Step 3

hold-time eigrp

as-num seconds

Example:

hostname(config)# hold-time eigrp 2 60

Changes the hold time.

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