Brocade Communications Systems ICX 6650 Dynamically refreshing routes

394 Brocade ICX 6650 Layer 3 Routing Configuration Guide

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Updating route information and resetting a neighbor session

•RFC 2918, which describes the dynamic route refresh capability

The dynamic route refresh capability is enabled by default and cannot be disabled. When the Layer

3 switch sends a BGP4 OPEN message to a neighbor, the Layer 3 switch includes a Capability

Advertisement to inform the neighbor that the Layer 3 switch supports dynamic route refresh.

NOTE

The option for dynamically refreshing routes received from a neighbor requires the neighbor to

support dynamic route refresh. If the neighbor does not support this feature, the option does not

take effect and the software displays an error message. The option for dynamically re-advertising

routes to a neighbor does not require the neighbor to support dynamic route refresh.

To use the dynamic refresh feature, use either of the following methods.

Dynamically refreshing routes

The following sections describe how to dynamically refresh BGP4 routes to place new or changed

filters into effect.

To request a dynamic refresh of all routes from a neighbor, enter a command such as the following.

Brocade(config-bgp-router)#clear ip bgp neighbor 192.168.1.170 soft in

This command asks the neighbor to send its BGP4 table (Adj-RIB-Out) again. The Layer 3 switch

applies its filters to the incoming routes and adds, modifies, or removes BGP4 routes as necessary.

out]]

The all | ip-addr | peer-group-name | as-num option specifies the neighbor. The ip-addr parameter

specifies a neighbor by its IP interface with the Layer 3 switch. The peer-group-name specifies all

neighbors in a specific peer group. The as-num parameter specifies all neighbors within the

specified AS. The all parameter specifies all neighbors.

The soft-outbound parameter updates all outbound routes by applying the new or changed filters,

but sends only the existing routes affected by the new or changed filters to the neighbor.

The soft [in | out] parameter specifies whether you want to refresh the routes received from the

neighbor or sent to the neighbor:

•soft in does one of the following:

-If you enabled soft reconfiguration for the neighbor or peer group, soft in updates the

routes by comparing the route policies against the route updates that the Layer 3 switch

has stored. Soft reconfiguration does not request additional updates from the neighbor or

otherwise affect the session with the neighbor. Refer to “Using soft reconfiguration” on

page391.

-If you did not enable soft reconfiguration, soft in requests the neighbor entire BGP4 route

table (Adj-RIB-Out), then applies the filters to add, change, or exclude routes.

-If a neighbor does not support dynamic refresh, soft in resets the neighbor session.

•soft out updates all outbound routes, then sends the Layer 3 switch entire BGP4 route table

(Adj-RIB-Out) to the neighbor, after changing or excluding the routes affected by the filters.

If you do not specify in or out, the Layer 3 switch performs both options.