HP 7102dl - ProCurve Secure Router Configuration Manual page 827

Follow these steps to set multi-exit discriminators:
1. Divide your network into various destinations for traffic. Divide the
network into as many sections as your organization has connections to
ISP routers. Determine which connections you would like external neigh-
bors to use for traffic destined to the various sections of the network.
Create a separate prefix list to select the set of routes to each section of
the network. For example, you could configure two prefix lists: one that
selects routes to one half of you network and one that selects routes to
the other half.
See "Filtering Advertised Routes According to Network Address" on page
15-92 or "Creating Prefix Lists: Configuring Filters for Route Exchange"
on page 15-81 to learn how to create the necessary lists.
2. You should configure a separate route map for each neighbor to which
your router connects. In each route map, you should configure a separate
route map entry for each set of routes that applies to a section of the
network.
3. First create the route map entry for the set of routes that you want to
advertise as preferable to the first neighbor:
Syntax: route-map <mapname> <sequence number>
4. Select the set of routes using a match command. You can use various
attributes to select routes, including the destination network address and
prefix length or community.
Classifying routes according to their destination address is the typical way
to group routes to one section of your network. Use a prefix list to select
these routes and then associate the prefix list with the route map entry.
Enter:
Syntax: match ip address prefix <listname>
5. Set the metric for the routes you have selected:
Syntax: set metric <value>
Enter a value between 0 and 429467295. Configure a lower metric than
that set for these routes in any other route map.
6. Configure a route map entry with the same name but different sequence
number for the set of routes to the next section of the network. Repeat
steps 3 through 5. You should configure a higher metric for these routes
than that you configured for the first set of routes.
Configure a route map entry for each section of the network.
IP Routing—Configuring RIP, OSPF, BGP, and PBR
Configuring BGP
15-101