Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 628)

• Applying policy changes without resetting neighbor
• Keepalive and hold time
• Specifying of routes not to be suppressed in route aggregation
• Specifying of source IP to be used in TCP connection to neighbor
• Adding of weight to each route received from neighbor
Peer groups
Neighbors having the same attributes and parameters can be grouped together by means of the peer-
group command. You must first create a peer-group, after which you can associate neighbor IP
addresses with the peer-group. All of the attributes that are allowed on a neighbor are allowed on a
peer-group as well.
Configurations for both creating a peer-group and associating neighbors to the peer-group are
available in BGP global mode. As an example, you can create a peer-group named "external-group"
as follows:
switch(config-bgp-router)# neighbor external-group peer-group
Subsequently, you can associate neighbors to "external-group," and configure attributes on the peer-
group as illustrated below:
switch(config-bgp-router)# neighbor 172.29.233.2 peer-group external-group
switch(config-bgp-router)# neighbor 10.120.121.2 peer-group external-group
switch(config-bgp-router)# neighbor external-group remote-as 1720
An attribute value configured explicitly for a neighbor takes precedence over the attribute value
configured on peer-group. In case neither the peer-group nor the individual neighbor has the attribute
configured, the default value for the attribute is used.
Four-byte AS numbers
Four-byte autonomous system numbers (ASNs) can be optionally configured on a device, peer-group,
or neighbor. If this is enabled, the device announces and negotiates "AS4" capability with its
neighbors. You can configure AS4 capability to be enabled or disabled at the BGP global level:
switch(config-bgp-router)# capability as4-enable
You can do the same at the neighbor or peer-group level:
switch(config-bgp-router)# neighbor 172.29.233.2 capability as4-enable
You can configure AS4 capability to be enabled for a neighbor while still keeping AS4 numbers
disabled at the global level, or vice-versa. The neighbor AS4 capability configuration takes
precedence. If AS4 capability is not configured on the neighbor, then the peer-group configuration
takes effect. The global configuration is used if AS4 capability is configured neither at the neighbor nor
at the peer-group level. If a device having a 4-byte ASN tries to connect to a device that does not have
AS4 support, peering will not be established.
Route redistribution
The redistribution of static, connected, and OSPF routes into BGP is supported. Similarly, routes
learned through BGP can also be redistributed into OSPF. An optional route-map can be specified,
and this map will be consulted before routes are added to BGP. Management routes are not
redistributed.
You configure redistribution under IPv4 address-family mode:
switch(config-bgp-router)# address-family ipv4 unicast
Peer groups
628 Network OS Administrator’s Guide
53-1003225-04