466CHAPTER 30: CONFIGURING BGP

peer and advertises it to other EBGP peers, it will try to check whether this destination can be reached through its AS.

Perform the following configurations in BGP view.

Table 549 Configure Synchronization of BGP and IGP

 

Operation

Command

 

 

 

 

Synchronize BGP with IGP

synchronization

 

 

 

 

Prohibit synchronizing BGP with IGP

undo synchronization

 

 

 

 

By default, BGP synchronizes with IGP.

 

3Com routers provide the ability to cancel BGP and IGP synchronization so the

 

route from IBGP can be distributed without continuously checking if the IGP route

 

still exists.

 

 

The synchronization of a border router can be shut down safely in the following

 

cases:

 

 

All the routers of an AS can form an IBGP totally-closed network. In such a

 

case, a route known from any border router's EBGP can be automatically

 

transferred to any other router through IBGP so that the connection of the AS

 

is insured.

 

 

When AS is not a transitional AS.

 

Configuring the

BGP can import route information that is found by running IGP in another AS to its

Interactions between

own AS.

 

BGP and an IGP

Perform the following configurations in BGP view.

 

 

Table 550 Configure Route Import for BGP

 

 

 

 

Operation

Command

 

 

 

 

Configure route import for BGP

import-route protocol [ med med ] [

 

 

route-policy policy-name]

 

 

 

 

Cancel route distribution for BGP

undo import-route protocol

 

 

 

By default, BGP does not import routes from other domains into the routing table.

The protocol attribute specifies the source routing domain that can be imported.

At present, BGP can import routes domain such as connected, static, RIP, OSPF and

OSPF-ASE.

See “Configure Route Import” in “Configuration of IP Routing Policy” for the details of routing import.

The import-routecommand cannot import the default route into BGP, so you must use the default-informationcommand to import the default route into BGP.

Perform the following configurations in BGP view.

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3Com 10014299 By default, BGP synchronizes with IGP, Still exists, Is insured When AS is not a transitional AS Configuring