Connectivity Guide

neighbor 32.1.1.2
remote-as 103
timers 61 181
no shutdown
Neighbor soft-reconguration
BGP soft-reconguration allows for fast and easy route changes. Changing routing policies requires a reset of BGP sessions or the TCP
connection, for the policies to take eect.
Resets cause undue interruption to trac due to the hard reset of the BGP cache, and the time it takes to re-establish the session. BGP
soft-reconguration allows for policies to apply to a session without clearing the BGP session. You can perform a soft-reconguration on a
per-neighbor basis, either inbound or outbound. BGP soft-reconguration clears the policies without resetting the TCP connection. After
conguring soft-reconguration, use the clear ip bgp command to make the neighbor use soft reconguration.
When you enable soft-reconguration for a neighbor and you execute the clear ip bgp soft in command, the update database
stored in the router replays and updates are re-evaluated. With this command, the replay and update process triggers only if a route-refresh
request is not negotiated with the peer. If the request is negotiated after using the clear ip bgp soft in command, BGP sends a
route-refresh request to the neighbor and receives all the peer’s updates.
To use soft reconguration, or soft reset without preconguration, both BGP peers must support soft route refresh. The soft route refresh
advertises in the OPEN message sent when the peers establish a TCP session. To determine whether a BGP router supports this capability,
use the show ip bgp neighbors command. If a router supports the route refresh capability, the Received route refresh
capability from peer
message displays.
1 Enable soft-reconguration for the BGP neighbor and BGP template in ROUTER-BGP mode. BGP stores all the updates that the
neighbor receives but does not reset the peer-session. Entering this command starts the storage of updates, which is required to do
inbound soft reconguration.
neighbor {ip-address} soft-reconfiguration inbound
2 Enter Address Family mode in ROUTER-NEIGHBOR mode.
address-family {[ipv4 | ipv6] [unicast]}
3 Congure soft-conguration for the neighbors belonging to the template.
soft-reconfiguration inbound
4 Clear all information or only specic details in EXEC mode.
clear ip bgp {neighbor-address | * } [soft in]
• * — Clears all peers.
• neighbor-address — Clears the neighbor with this IP address.
Soft-reconguration of IPv4 neighbor
OS10(conf-router-neighbor)# address-family ipv4 unicast
OS10(conf-router-bgp-neighbor-af)# soft-reconfiguration inbound
Soft-reconguration of IPv6 neighbor
OS10(conf-router-neighbor)# address-family ipv6 unicast
OS10(conf-router-bgp-neighbor-af)# soft-reconfiguration inbound
BGP commands
Layer 3
459