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BGP soft-reconfiguration clears the policies without resetting the TCP connection.
To reset a BGP connection using BGP soft-reconfiguration, 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 configuration 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 filters. 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 configured with this command.
● Enable soft-reconfiguration for the BGP neighbor specified.
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-reconfiguration. Outbound BGP
soft-reconfiguration does not require inbound soft-reconfiguration to be enabled.
● Reset BGP connection using soft-reconfiguration.
EXEC Privilege mode
clear ip bgp [vrf vrf-name] [* | neighbor-address | as-number | peer-group-name] {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.
○ peer-group-name: Clears all members of the specified peer group.
The example enables inbound soft-reconfiguration for the neighbor 10.108.1.1. All updates received from this neighbor are stored
unmodified, regardless of the inbound policy. When inbound soft-reconfiguration is done later, the stored information is used to
generate a new set of inbound updates
DellEMC(conf)# router bgp 100
DellEMC(conf-router_bgp)# neighbor 10.108.1.1 remote-as 20
DellEMC(conf-router_bgp)# neighbor 10.108.1.1 soft-reconfiguration inbound
DellEMC(conf-router_bgp)# exit
Route-refresh
This section explains how the soft-reconfiguration and route-refresh works. Soft-reconfiguration has to be configured explicitly
for a neighbor unlike route refresh, which is automatically negotiated between BGP peers when establishing a peer session.
The route-refresh updates will be sent, only if the neighbor soft-reconfiguration inbound command is not
configured in a BGP neighbor and when you do a soft reset using clear ip bgp {neighbor-address | peer-group-
name} soft in command.
If the neighbor soft-reconfiguration inbound command is already configured in the BGP neighbor, the route
refresh updates will not be sent. If you want to use route-refresh updates instead, remove the neighbor soft-
reconfiguration inbound configuration and do a hard reset once, using clear ip bgp {* | as-number | ipv4|
ipv6 | neighbor-address | peer-group-name} command. If you remove neighbor soft-reconfiguration
inbound configuration for an individual neighbor (not part of peer-group), it is sufficient to do a hard reset only for the
individual neighbor. If the neighbor is part of a peer-group and when neighbor soft-reconfiguration inbound is
removed from the peer group, you need to do a hard reset for the peer-group.
Border Gateway Protocol (BGP)
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