Huawei S6700 Series Configuration Manual page 422

S6700 Series Ethernet Switches
Configuration Guide - IP Routing
Context
After changing a BGP import policy, you must reset BGP connections for the new import policy
to take effect, interrupting these BGP connections temporarily. BGP route-refresh allows the
system to refresh a BGP routing table dynamically without tearing down any BGP connection
if routing policies are changed.
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Perform the following steps on a BGP switch:
Procedure
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Issue 01 (2012-03-15)
If a device's peer supports route-refresh, the refresh bgp command can be used on the
device to softly reset the BGP connection with the peer and update the BGP routing table.
If a device's peer does not support route-refresh, the peer keep-all-routes command can
be used on the device to remain all routing updates received from the peer so that the device
can refresh its routing table without closing the connection with the peer.
If the device's peers support route-refresh, perform the following operations:
1. (Optional) Enable route-refresh.
a. Run:
system-view
The system view is displayed.
b. Run:
bgp as-number
The BGP view is displayed.
c. Run:
peer { ipv4-address | group-name } capability-advertise route-refresh
Route-refresh is enabled.
By default, route-refresh is enabled.
If route-refresh is enabled on all BGP switches and the import policy of the local
switch is changed, the local switch sends a route-refresh message to peers or peer
groups. After receiving the message, the peers or peer groups resend routing
information to the local BGP switch. This enables the local switch to dynamically
refresh its BGP routing table and apply the new routing policy without closing any
BGP connections.
2. Configure BGP soft reset.
a. Run the refresh bgp [ vpn-instance vpn-instance-name ipv4-family ] { all |
ipv4-address | group group-name | external | internal } { export | import }
command in the user view to softly reset the BGP connections between the
devices and its peers or peer groups.
external softly resets an EBGP connection, and internal softly resets an IBGP
connection.
export triggers outbound BGP soft reset, and import triggers inbound BGP soft reset.
If the device's peers do not support route-refresh, perform the following operations:
– Configure the device to store all the routing updates received from its peers or peer
groups.
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