Using Soft Reconfiguration - Dell PowerConnect B-RX Configuration Manual

Using soft reconfiguration

The soft reconfiguration feature places policy changes into effect without resetting the BGP4
session. Soft reconfiguration does not request the neighbor or group to send its entire BGP4 table,
nor does the feature reset the session with the neighbor or group. Instead, the soft reconfiguration
feature stores all the route updates received from the neighbor or group. When you request a soft
reset of inbound routes, the software performs route selection by comparing the policies against
the stored route updates, instead of requesting the neighbor's BGP4 route table or resetting the
session with the neighbor.
When you enable the soft reconfiguration feature, it sends a refresh message to the neighbor or
group if the neighbor or group supports dynamic refresh. Otherwise, the feature resets the
neighbor session. This step is required to ensure that the soft reconfiguration feature has a
complete set of updates to use, and occurs only once, when you enable the feature. The feature
accumulates all the route updates from the neighbor, eliminating the need for additional refreshes
or resets when you change policies in the future.
To use soft reconfiguration:
•
•
•
Enabling soft reconfiguration
To configure a neighbor for soft reconfiguration, enter a command such as the following.
BigIron RX(config-bgp)# neighbor 10.10.200.102 soft-reconfiguration inbound
This command enables soft reconfiguration for updates received from 10.10.200.102. The
software dynamically refreshes or resets the session with the neighbor, then retains all route
updates from the neighbor following the reset.
Syntax: [no] neighbor <ip-addr> | <peer-group-name> soft-reconfiguration inbound
NOTE
The syntax related to soft reconfiguration is shown. For complete command syntax, refer to
"Configuring BGP4 neighbors"
Placing a policy change into effect
To place policy changes into effect, enter a command such as the following.
BigIron RX(config-bgp)# clear ip bgp neighbor 10.10.200.102 soft in
This command updates the routes by comparing the route policies against the route updates that
the device has stored. The command does not request additional updates from the neighbor or
otherwise affect the session with the neighbor.
Syntax: clear ip bgp neighbor <ip-addr> | <peer-group-name> soft in
NOTE
If you do not specify "in", the command applies to both inbound and outbound updates.
BigIron RX Series Configuration Guide
53-1002253-01
Enable the feature.
Make the policy changes.
Apply the changes by requesting a soft reset of the inbound updates from the neighbor or
group.
on page 771 and "Configuring a BGP4 peer group"
26
Filtering
on page 778.
817