The rst two commands congure statements for the IP prex list Routesfrom1234. The rst command congures a statement that
denies routes to 10.20.20./24. The second command congures a statement that permits all other routes. Once you congure an IP
prex list statement, all routes not explicitly permitted by statements in the prex list are denied.
The next two commands change the CLI to the BGP4 conguration level, then apply the IP prex list to neighbor 10.2.3.4. The last
command enables the device to send the IP prex list as an ORF to neighbor 10.2.3.4. When the device sends the IP prex list to the
neighbor, the neighbor lters out the 10.20.0.x routes from its updates to the device. This assumes that the neighbor is also congured
for cooperative ltering.
Syntax: [no] neighbor ip-addr | peer-group-name capability orf prexlist [ send | receive ]
The ip-addr | peer-group-name parameters specify the IP address of a neighbor or the name of a peer group of neighbors.
The send and receive parameters specify the support you are enabling:
• send - The device sends the IP prex lists to the neighbor.
• receive - The device accepts lters from the neighbor.
If you do not specify the capability, both capabilities are enabled.
The prexlist parameter species the type of lter you want to send to the neighbor.
NOTE
The current release supports cooperative ltering only for lters congured using IP prex
lists.
Sending and receiving ORFs
Cooperative
ltering aects neighbor sessions that start after the ltering is enabled, but do not aect sessions that are already
established.
To activate cooperative ltering, reset the session with the neighbor. This is required because the cooperative ltering information is
exchanged in Open messages during the start of a session.
To place a prex-list change into eect after activating cooperative ltering, perform a soft reset of the neighbor session. A soft reset
does not end the current session, but sends the prex list to the neighbor in the next route refresh message.
NOTE
Make sure cooperative ltering is enabled on the device and on the neighbor before you send the
lters.
To reset a neighbor session and send ORFs to the neighbor, enter a command such as the following.
device# clear ip bgp neighbor 10.2.3.4
This command resets the BGP4 session with neighbor 10.2.3.4 and sends the ORFs to the neighbor. If the neighbor sends ORFs to the
device, the device accepts them if the send capability is enabled.
To perform a soft reset of a neighbor session and send ORFs to the neighbor, enter a command such as the following.
device# clear ip bgp neighbor 10.2.3.4 soft in prefix-list
Syntax: clear ip bgp neighbor ip-addr [ soft in prex-lter | soft in prex-list ]
If you use the soft in prex-lter parameter, the device sends the updated IP prex list to the neighbor as part of its route refresh
message to the neighbor.
Filtering
FastIron Ethernet Switch Layer 3 Routing
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