Brocade Communications Systems ICX 7250 series, Руководство по настройке

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• IGP metric to BGP next hop
Route maps
Route maps must be applied to IPv6 unicast address prefixes in IPv6 address family configuration mode.
By default, route maps that are applied under IPv4 address family configuration mode using the neighbor route-map command are
applied to only IPv4 unicast address prefixes. To apply route maps to IPv6 unicast address prefixes, the neighbor route-map command
must be used in IPv6 address family configuration mode. The route maps are applied as the inbound or outbound routing policy for
neighbors under the specified address family. Configuring separate route maps under each address family type simplifies managing
complicated or different policies for each address family.
BGP4+ outbound route filtering
The BGP4+ Outbound Route Filtering Capability (ORF) feature is used to minimize the number of BGP updates sent between BGP
peers.
When the ORF feature is enabled, unwanted routing updates are filtered out, reducing the amount of system resources required for
generating and processing routing updates. The ORF feature is enabled through the advertisement of ORF capabilities to peer routers.
The locally configured BGP4+ inbound prefix filters are sent to the remote peer so that the remote peer applies the filter as an outbound
filter for the neighbor.
The ORF feature can be configured with send and receive ORF capabilities. The local peer advertises the ORF capability in send mode,
indicating that it will accept a prefix list from a neighbor and apply the prefix list to locally configured ORFs. The local peer exchanges the
ORF capability in send mode with a remote peer for a prefix list that is configured as an inbound filter for that peer locally. The remote
peer only sends the first update once it receives a ROUTEREFRESH request or BGP ORF with IMMEDIATE from the peer. The local
and remote peers exchange updates to maintain the ORF on each router.
BGP4+ confederations
A large autonomous system (AS) can be divided into multiple subautonomous systems and grouped into a single BGP4+ confederation.
Each subautonomous system must be uniquely identified within the confederation AS by a subautonomous system number. Within each
subautonomous system, all the rules of internal BGP (IBGP) apply. For example, all BGP routers inside the subautonomous system must
be fully meshed. Although EBGP is used between subautonomous systems, the subautonomous systems within the confederation
exchange routing information like IBGP peers. Next hop, Multi Exit Discriminator (MED), and local preference information is preserved
when crossing subautonomous system boundaries. To the outside world, a confederation looks like a single AS.
The AS path list is a loop-avoidance mechanism used to detect routing updates leaving one subautonomous system and attempting to
re-enter the same subautonomous system. A routing update attempting to re-enter a subautonomous system it originated from is
detected because the subautonomous system sees its own subautonomous system number listed in the update's AS path.
Route maps
Brocade FastIron Layer 3 Routing Configuration Guide
402 53-1003903-04