Concept Guide

In the above example conguration, the BGP timers are set with keepalive time as 80 seconds with which the system sends keepalive
messages to the BGP peer and holdtime as 120 seconds with which the system waits for a message from the BGP peer before concluding
that the peer is dead.
To view non-default values, use the show config command in CONFIGURATION ROUTER BGP mode or the show running-
config bgp command in EXEC Privilege mode.
Route-refresh and Soft-reconguration
BGP soft-reconguration allows for faster and easier route changing.
Changing routing policies typically requires a reset of BGP sessions (the TCP connection) for the policies to take eect. Such resets cause
undue interruption to trac due to hard reset of the BGP cache and the time it takes to re-establish the session. BGP soft-reconguration
allows for policies to be applied to a session without clearing the BGP Session. Soft-reconguration can be done on a per-neighbor basis
and can either be inbound or outbound.
BGP soft-reconguration clears the policies without resetting the TCP connection.
To reset a BGP connection using BGP soft-reconguration, use the clear ip bgp command in EXEC Privilege mode at the system
prompt.
When you change the BGP inbound policy locally, you need to process the updates received from a peer. The route-refresh capability allows
the local peer to reset inbound information dynamically by exchanging route-refresh requests to supporting peers. When an inbound policy
conguration is changed, then the Dell EMC Networking OS sends a refresh request message asking the peer to re-advertise updates.
Upon receiving the refresh request, the peer advertises the required information after applying the outbound lters. Route-refresh is
negotiated during the BGP session establishment and will be used only if both the BGP peers support this capability.
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 following message displays:
Received route refresh capability from peer.
If you specify a BGP peer group by using the peer-group-name argument, all members of the peer group inherit the characteristic
congured with this command.
• Enable soft-reconguration for the BGP neighbor specied.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | ipv6-address | peer-group-name} soft-reconfiguration inbound
BGP stores all the updates received by the neighbor but does not reset the peer-session.
Entering this command starts the storage of updates, which is required to do inbound soft-reconguration. Outbound BGP soft-
reconguration does not require inbound soft-reconguration to be enabled.
• Reset BGP connection using soft-reconguration.
EXEC Privilege mode
clear ip bgp [vrf vrf-name] [* | neighbor-address | as-number | ipv4 | ipv6 | peer-group-name
| dampening | flap-statistics] {soft {in | out}}
– *: Clears all peers.
– neighbor-address: Clears the IPv4 or IPv6 neighbor of this IP address.
– as-number: Clears the peers AS numbers.
– ipv4: Clears information for the IPv4 address family.
– ipv6: Clears information for the IPv6 address family.
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BGP IP version 4 (BGPv4) Overview