Changing Policies Without Disruption; Soft Reconfiguration - Juniper BGP - CONFIGURATION GUIDE V 11.1.X Configuration Manual

Changing Policies Without Disruption

Changing policies can cause major network disruptions when you bring down sessions
to reapply the modified policies. You can use either of the methods in this section
to minimize network disruptions.

Soft Reconfiguration

You can use soft reconfiguration to enable the nondisruptive reapplication of inbound
policies. Issuing the command causes the router to store copies of the routes received
from the specified peer or from all members of the specified peer group. The route
copies are stored unmodified, before application of inbound policies.
If you then change your inbound policies, you can apply them to the stored routes
without clearing your BGP sessions and causing network disruptions by issuing
the clear ip bgp soft in command.
neighbor soft-reconfiguration inbound
Use the soft out option to reapply outbound policy and resend routes without
clearing the BGP session.
This command takes effect immediately.
There is no no version.
See clear bgp ipv6.
See clear ip bgp.
Use to initiate the storage of copies of routes received from the specified IP
address or from all members of the specified peer group.
Use with the clear ip bgp soft in command to reapply inbound policies to stored
routes without clearing the BGP sessions.
Example
host1(config)#router bgp 37
host1(config-router)#neighbor 192.168.1.1 remote-as 42
host1(config-router)#neighbor 192.168.1.1 soft-reconfiguration inbound
If you specify a BGP peer group by using the peerGroupName argument, all the
members of the peer group inherit the characteristic configured with this
command unless it is overridden for a specific peer.
If the route-refresh capability was negotiated with the peer, BGP immediately
sends a route-refresh message to the peer to populate the Adj-RIBs-In table.
If the route-refresh capability was not negotiated with the peer, BGP automatically
bounces the session. The Adj-RIBs-In table is repopulated when routes are
received from the peer after the session comes back up.
Chapter 1: Configuring BGP Routing
Configuring BGP Routing Policy
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