Configuration Guide User guide

FastIron Configuration Guide 1361
53-1002494-02
Basic configuration tasks required for BGP4
Adding a BGP4 peer group
A peer group is a set of BGP4 neighbors that share common parameters. Peer groups provide the
following benefits:
• Simplified neighbor configuration – You can configure a set of neighbor parameters and then
apply them to multiple neighbors. You do not need to individually configure the common
parameters individually on each neighbor.
• Flash memory conservation – Using peer groups instead of individually configuring all the
parameters for each neighbor requires fewer configuration commands in the startup-config
file.
You can perform the following tasks on a peer-group basis:
• Reset neighbor sessions
• Perform soft-outbound resets (the Layer 3 switch updates outgoing route information to
neighbors but does not entirely reset the sessions with those neighbors)
• Clear BGP message statistics
• Clear error buffers
Peer group parameters
You can set all neighbor parameters in a peer group. When you add a neighbor to the peer group,
the neighbor receives all the parameter settings you set in the group, except parameter values you
have explicitly configured for the neighbor. If you do not set a neighbor parameter in the peer group
and the parameter also is not set for the individual neighbor, the neighbor uses the default value.
Peer group configuration rules
The following rules apply to peer group configuration:
• You must configure a peer group before you can add neighbors to the peer group.
• If you remove a parameter from a peer group, the value for that parameter is reset to the
default for all the neighbors within the peer group, unless you have explicitly set that parameter
on individual neighbors. In this case, the value you set on the individual neighbors applies to
those neighbors, while the default value applies to neighbors for which you have not explicitly
set the value.
NOTE
If you enter a command to remove the remote AS parameter from a peer group, the software
checks to ensure that the peer group does not contain any neighbors. If the peer group does
contain neighbors, the software does not allow you to remove the remote AS. The software
prevents removing the remote AS in this case so that the neighbors in the peer group that are
using the remote AS do not lose connectivity to the Layer 3 switch.
• Once you add a neighbor to a peer group, you cannot configure the following outbound
parameters (the parameters governing outbound traffic) for the neighbor:
• Default-information-originate
• Next-hop-self
• Outbound route map
• Outbound filter list