Configuring BGP
Configuring Redistribution
OmniSwitch AOS Release 7 Advanced Routing Configuration Guide
March 2011
page 3-53
Configuring Redistribution
It is possible to configure the BGP protocol to advertise routes learned from other routing protocols (exter-
nal routes) into the BGP network. Such a process is referred to as route redistribution and is configured
using the
ip redist
command.
BGP redistribution uses route maps to control how external routes are learned and distributed. A route
map consists of one or more user-defined statements that can determine which routes are allowed or
denied access to the BGP network. In addition a route map may also contain statements that modify route
parameters before they are redistributed.
When a route map is created, it is given a name to identify the group of statements that it represents. This
name is required by the
ip redist
command. Therefore, configuring BGP route redistribution involves the
following steps:
1
Create a route map, as described in
“Using Route Maps” on page 3-53
.
2
Configure redistribution to apply a route map, as described in
“Configuring Route Map Redistribu-
tion” on page 3-57
.
Using Route Maps
A route map specifies the criteria that are used to control redistribution of routes between protocols. Such
criteria is defined by configuring route map statements. There are three different types of statements:
•
Action
. An action statement configures the route map name, sequence number, and whether or not
redistribution is permitted or denied based on route map criteria.
•
Match.
A match statement specifies criteria that a route must match. When a match occurs, then the
action statement is applied to the route.
•
Set.
A set statement is used to modify route information before the route is redistributed into the
receiving protocol. This statement is only applied if all the criteria of the route map is met and the
action permits redistribution.
The
ip route-map
command is used to configure route map statements and provides the following
action
,
match
, and
set
parameters:
Refer to the “IP Commands” chapter in the
OmniSwitch CLI Reference Guide
for more information about
the ip route-map command parameters and usage guidelines.
Once a route map is created, it is then applied using the
ip redist
command. See
“Configuring Route Map
Redistribution” on page 3-57
for more information.
ip route-map action ...
ip route-map match ...
ip route-map set ...
permit
deny
ip-address
ip-nexthop
ipv6-address
ipv6-nexthop
tag
ipv4-interface
ipv6-interface
metric
route-type
metric
metric-type
tag
community
local-preference
level
ip-nexthop
ipv6-nexthop
