Configuring BGP4

USING THE CLI

To change the default administrative distances for EBGP, IBGP, and Local BGP, enter a command such as the following:

HP9300(config-bgp-router)# distance 180 160 40

Syntax: distance <external-distance> <internal-distance> <local-distance>

The <external-distance> sets the EBGP distance and can be a value from 1 – 255.

The <internal-distance> sets the IBGP distance and can be a value from 1 – 255.

The <local-distance> sets the Local BGP distance and can be a value from 1 – 255.

USING THE WEB MANAGEMENT INTERFACE

1.Log on to the device using a valid user name and password for read-write access. The System configuration panel is displayed.

2.Click on the plus sign next to Configure in the tree view to expand the list of configuration options.

3.Click on the plus sign next to BGP in the tree view to expand the list of BGP option links.

4.Click on the General link to display the BGP configuration panel, shown in Figure 10.2 on page 10-8.

5.Change the number in the External Distance field to change the EBGP distance. You can enter a number from 1 – 255.

6.Change the number in the Internal Distance field to change the IBGP distance. You can enter a number from

1– 255.

7.Change the number in the Local Distance field to change the local distance. You can enter a number from

1– 255.

8.Click the Apply button to apply the changes to the device’s running-config file.

9.Select the Save link at the bottom of the dialog. Select Yes when prompted to save the configuration change to the startup-config file on the device’s flash memory.

Configuring the routing switch To Always Compare Multi-Exit Discriminators (MEDs)

A Multi-Exit Discriminator (MED) is a value that the BGP4 algorithm uses when comparing multiple paths received from different BGP4 neighbors in the same AS for the same route. In BGP4, a route’s MED is equivalent to its “metric”.

By default, the routing switch compares the MED values only among paths through the same AS. For example, if the routing switch receives BGP4 updates from a remote AS with multiple paths for the same route, the routing switch compares the MEDs in those paths to select a preferred path for the route.

You can change the routing switch’s default behavior and configure the routing switch to instead compare the MEDs for all paths for a route, regardless of the AS through which the paths pass. For example, if the routing switch receives UPDATES for the same route from neighbors in three ASs, the routing switch would compare the MEDs of all the paths together, rather than comparing the MEDs for the paths in each AS individually.

To configure the routing switch to always compare MEDs for all paths for a route, use either of the following methods:

USING THE CLI

To configure the routing switch to always compare MEDs, enter the following command:

HP9300(config-bgp-router)# always-compare-med

Syntax: [no] always-compare-med

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