Dell S50V Switch User Manual


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264 | Border Gateway Protocol IPv4 (BGPv4)
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Use the clear ip bgp command in EXEC Privilege mode to reset a BGP connection using BGP soft
reconfiguration.
When inbound soft reconfiguration is enabled on a neighbor and you enter the
clear ip bgp soft in
command, the update database stored in the router is replayed and updates are reevaluated. The replay and
update process is triggered only if a route-refresh request is not negotiated with the peer. If a route-refresh
request is negotiated, BGP sends a request to the neighbor and receives all of the peer’s updates.
To use soft reconfiguration (or soft reset) without preconfiguration, both BGP peers must support the soft
route refresh capability, which is advertised 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 following message is displayed:
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.
The following example (Figure 10-33) shows how to enable 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 performed later, the stored information is used to generate a
new set of inbound updates.
Figure 10-33. Command example: router bgp
Command Syntax Command Mode Purpose
neighbor {ipv4-address | ipv6-address |
peer-group-name} soft-reconfiguration
inbound
CONFIG-ROUTER-
BGP
Enable inbound soft-reconfiguration for the
specified BGP neighbor. BGP stores all updates
received by the neighbor but does not reset the peer
session.
Entering this command starts the storage of updates on inbound routes,
which is required for inbound soft reconfiguration. Outbound BGP soft
reconfiguration does not require inbound soft reconfiguration to be enabled.
clear ip bgp { * | as-number | ipv4-
neighbor-addr | ipv6-neighbor-addr |
peer-group name} {ipv4 unicast | ipv4
multicast
| ipv6 unicast} soft [in | out]
EXEC Privilege Clears and reapplies policies on:
*: All peers
as-number: BGP routers that belong to the specified
AS
neighbor-addr: BGP neighbor with specified IP
address
Type of routes to be reapplied:
ipv4 unicast, ipv4 multicast, or ipv6 unicast
in: Reapplies only inbound policies
out: Reapplies only outbound policies
FTOS>router bgp 100
neighbor 10.108.1.1 remote-as 200
neighbor 10.108.1.1 soft-reconfiguration inbound