Brocade Communications Systems ICX 7250 series, Configuration Manual

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device(config-routemap TAG_IP)# set tag 100
device(config-routemap TAG_IP)# router bgp
device(config-bgp)# table-map TAG_IP
Configuring cooperative BGP4 route filtering
By default, the device performs all filtering of incoming routes locally, on the device itself. You can use cooperative BGP4 route filtering
to cause the filtering to be performed by a neighbor before it sends the routes to the device. Cooperative filtering conserves resources by
eliminating unnecessary route updates and filter processing. For example, the device can send a deny filter to a neighbor, which the
neighbor uses to filter out updates before sending them to the device. The neighbor saves the resources it would otherwise use to
generate the route updates, and the device saves the resources it would use to filter out the routes.
When you enable cooperative filtering, the device advertises this capability in its Open message to the neighbor when initiating the
neighbor session. The Open message also indicates whether the device is configured to send filters, receive filters, or both, and the types
of filters it can send or receive. The device sends the filters as Outbound Route Filters (ORFs) in route refresh messages.
To configure cooperative filtering, perform the following tasks on the device and on the BGP4 neighbor:
• Configure the filter.
NOTE
Cooperative filtering is currently supported only for filters configured using IP prefix
lists.
• Apply the filter as an inbound filter to the neighbor.
• Enable the cooperative route filtering feature on the device. You can enable the device to send ORFs to the neighbor, to receive
ORFs from the neighbor, or both. The neighbor uses the ORFs you send as outbound filters when it sends routes to the device.
Likewise, the device uses the ORFs it receives from the neighbor as outbound filters when sending routes to the neighbor.
• Reset the BGP4 neighbor session to send and receive ORFs.
• Perform these steps on the other device.
NOTE
If the device has inbound filters, the filters are still processed even if equivalent filters have been sent as ORFs to the
neighbor.
Enabling cooperative filtering
To configure cooperative filtering, enter commands such as the following.
device(config)# ip prefix-list Routesfrom10234 deny 10.20.0.0/24
device(config)# ip prefix-list Routesfrom10234 permit 0.0.0.0/0 le 32
device(config)# router bgp
device(config-bgp-router)# neighbor 10.2.3.4 prefix-list Routesfrom1234 in
device(config-bgp-router)# neighbor 10.2.3.4 capability orf prefixlist send
The first two commands configure statements for the IP prefix list Routesfrom1234. The first command configures a statement that
denies routes to 10.20.20./24. The second command configures a statement that permits all other routes. Once you configure an IP
prefix list statement, all routes not explicitly permitted by statements in the prefix list are denied.
The next two commands change the CLI to the BGP4 configuration level, then apply the IP prefix list to neighbor 10.2.3.4. The last
command enables the device to send the IP prefix list as an ORF to neighbor 10.2.3.4. When the device sends the IP prefix list to the
neighbor, the neighbor filters out the 10.20.0.x routes from its updates to the device. This assumes that the neighbor is also configured
for cooperative filtering.
Filtering
Brocade FastIron Layer 3 Routing Configuration Guide
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