Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 534)

The advertise-map map-name parameter configures the device to advertise the more specific routes
in the specified route map.
The attribute-map map-name parameter configures the device to set attributes for the aggregate
routes based on the specified route map.
NOTE
For the suppress-map, advertise-map, and attribute-map parameters, the route map must already
be defined.
To remove an aggregate route from a BGP4 neighbor advertisement, use the no form of this
command without any parameters.
Using route maps
You can use a route map to filter and change values in BGP4+ routes. Currently, you can apply a
route map to IPv6 unicast routes that are independent of IPv4 routes.
To configure a route map to match on IPv6 unicast routes, enter commands such as the following.
device(config)# router bgp
device(config-bgp-router)# address-family ipv6 unicast
device(config-bgp-ipv6u)# neighbor 2001:db8:df78::67 remote-as 1001
device(config-bgp-ipv6u)# neighbor 2001:db8:df78::67 route-map in map1
device(config-bgp-ipv6u)# exit
device(config)# ipv6 prefix-list ipv6_uni seq 10 permit 2001:db8::/32
device(config)# route-map map1 permit 10
device(config-routemap-map1)# match ipv6 address prefix-list ipv6_uni
This example configures a route map named "map1" that permits incoming IPv6 unicast routes that
match the prefix list named "ipv6_uni" (2001:db8::/32). Note that you apply the route map while at the
BGP4+ unicast address family configuration level.
Enabling next-hop recursion
For each BGP4+ route learned, the device performs a route lookup to obtain the IPv6 address of the
next-hop for the route. A BGP4+ route is eligible for addition in the IPv6 route table only if the following
conditions are true:
• The lookup succeeds in obtaining a valid next-hop IPv6 address for the route.
• The path to the next-hop IPv6 address is an IGP path or a static route path.
By default, the software performs only one lookup for the next-hop IPv6 address for the BGP4+ route.
If the next-hop lookup does not result in a valid next-hop IPv6 address, or the path to the next-hop
IPv6 address is a BGP4+ path, the software considers the BGP4+ route destination to be
unreachable. The route is not eligible to be added to the IPv6 route table.
The BGP4+ route table can contain a route with a next-hop IPv6 address that is not reachable through
an IGP route, even though the device can reach a hop farther away through an IGP route. This can
occur when the IGPs do not learn a complete set of IGP routes, so the device learns about an internal
route through IBGP instead of through an IGP. In this case, the IPv6 route table will not contain a route
that can be used to reach the BGP4+ route destination.
To enable the device to find the IGP route to the next-hop gateway for a BGP4+ route, enable
recursive next-hop lookups. With this feature enabled, if the first lookup for a BGP4+ route results in
an IBGP path that originated within the same AS, rather than an IGP path or static route path, the
device performs a lookup on the next-hop IPv6 address for the next-hop gateway. If this second
lookup results in an IGP path, the software considers the BGP4+ route to be valid and adds it to the
Using route maps
534 FastIron Ethernet Switch Layer 3 Routing Configuration Guide
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