Dell BigIron RX Series, Configuration Manual

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BigIron RX Series Configuration Guide 779
53-1002253-01
Configuring a BGP4 peer group
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You must configure a peer group before you can add neighbors to the peer group.
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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 device.
You can override neighbor parameters on an individual neighbor basis.
•
If you do not specify a parameter for an individual neighbor, the neighbor uses the value in the
peer group.
•
If you set the parameter for the individual neighbor, that value overrides the value you set in
the peer group.
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If you add a parameter to a peer group that already contains neighbors, the parameter value is
applied to neighbors that do not already have the parameter explicitly set. If a neighbor has
the parameter explicitly set, the explicitly set value overrides the value you set for the peer
group.
•
If you remove the setting for a parameter from a peer group, the value for that parameter
changes to the default value for all the neighbors in the peer group that do not have that
parameter individually set.
Configuring a peer group
To configure a peer group, enter commands such as the following at the BGP configuration level.
BigIron RX(config-bgp)# neighbor PeerGroup1 peer-group
BigIron RX(config-bgp)# neighbor PeerGroup1 description “EastCoast Neighbors”
BigIron RX(config-bgp)# neighbor PeerGroup1 remote-as 100
BigIron RX(config-bgp)# neighbor PeerGroup1 distribute-list out 1
The commands in this example configure a peer group called “PeerGroup1” and set the following
parameters for the peer group:
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A description, “EastCoast Neighbors”
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A remote AS number, 100
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A distribute list for outbound traffic
The software applies these parameters to each neighbor you add to the peer group. You can
override the description parameter for individual neighbors. If you set the description parameter
for an individual neighbor, the description overrides the description configured for the peer group.
Syntax: neighbor <peer-group-name> peer-group