Foundry Configuration Guide for the FESX, FSX, and FWSX
21 - 56 © Foundry Networks, Inc. December 2005
configured to send filters, receive filters or both, and the types of filters it can send or receive. The Layer 3 Switch
sends the filters as Outbound Route Filters (ORFs) in Route Refresh messages.
To configure cooperative filtering, perform the following tasks on the Layer 3 Switch and on its BGP4 neighbor:
• Configure the filter.
NOTE: The current release supports cooperative filtering only for filters configured using IP prefix lists.
• Apply the filter as in inbound filter to the neighbor.
• Enable the cooperative route filtering feature on the Layer 3 Switch. You can enable the Layer 3 Switch 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 Layer 3 Switch. Likewise, the Layer 3 Switch 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 Layer 3 Switch 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:
FESX424 Router(config)# ip prefix-list Routesfrom1234 deny 20.20.0.0/24
FESX424 Router(config)# ip prefix-list Routesfrom1234 permit 0.0.0.0/0 le 32
FESX424 Router(config)# router bgp
FESX424 Router(config-bgp-router)# neighbor 1.2.3.4 prefix-list Routesfrom1234 in
FESX424 Router(config-bgp-router)# neighbor 1.2.3.4 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 20.20.20./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
1.2.3.4. The last command enables the Layer 3 Switch to send the IP prefix list as an ORF to neighbor 1.2.3.4.
When the Layer 3 Switch sends the IP prefix list to the neighbor, the neighbor filters out the 20.20.0.x routes from
its updates to the Layer 3 Switch. (This assumes that the neighbor also is configured for cooperative filtering.)
Syntax: [no] neighbor <ip-addr> | <peer-group-name> capability orf prefixlist [send | receive]
The <ip-addr> | <peer-group-name> parameter specifies the IP address of a neighbor or the name of a peer group
of neighbors.
The send | receive parameter specifies the support you are enabling:
• send – The Layer 3 Switch sends the IP prefix lists to the neighbor.
• receive – The Layer 3 Switch accepts filters from the neighbor.
If you do not specify the capability, both capabilities are enabled.
The prefixlist parameter specifies the type of filter you want to send to the neighbor.
NOTE: The current release supports cooperative filtering only for filters configured using IP prefix lists.
Sending and Receiving ORFs
Cooperative filtering affects neighbor sessions that start after the filtering is enabled, but do not affect sessions
that are already established.
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