D-Link DI-1750 Reference Manual page 250

6.12.8 Configure BGP Neighbors
The purpose of BGP configuration is establishing the project of exchange route information. BGP must
be configured neighbors for exchange the route information with outside.
BGP supports two kinds of neighbors: internal and external. Internal neighbors are in the same
autonomous system; external neighbors are in different autonomous systems. Normally, external
neighbors are adjacent to each other and share a subnet, while internal neighbors may be anywhere in
the same autonomous system.
To configure BGP neighbors, use the following command in router configuration mode:
neighbor {ip-address | peer-group-name} remote-as
number
In the prompt Select 12 option ,prompt is as below:
(00)A.B.C.D
Please Input the code of command to be excute(0-0): 0
input 0，Select A.B.C.D option ，prompt is as below:
Please input a IP Address:
input IP ，then prompt is as below:
(00)default-originate
......
(08)remote-as
......
Please Input the code of command to be excute(0-17): 8
input 8，Select remote-as option ，prompt is as below:
(00)<1-65535>
Please Input the code of command to be excute(0-0): 0
input 0，prompt is as below:
Please input a digital number:Please input a string:
input number value ，prompt is as below:
(00)passive
(01)<cr>
Please Input the code of command to be excute(0-1): 1
Select 1 and confirm it.
See the "BGP Neighbor Configuration Examples" section at the end of this chapter for an example of
configuring BGP neighbors.
6.12.9 Configure BGP Soft Reconfiguration
Normally, BGP neighbor only exchanges all the routes while establishing the connection, after that only
the variable route can be exchanged. Whenever there is a change in the policy, the BGP session has to
be cleared for the new policy to take effect. Clearing a BGP session causes cache invalidation and
results in a tremendous impact on the operation of networks. Soft reconfiguration allows policies to be
configured and activated without clearing the BGP session. Soft reconfiguration is recommended; it is
done on a per-neighbor basis. When soft reconfiguration is used to generate inbound updates from a
neighbor, it is called inbound soft reconfiguration. When soft reconfiguration is used to send a new set
of updates to a neighbor, it is called outbound soft reconfiguration. Performing inbound reconfiguration
enables the new inbound policy to take effect. Performing outbound reconfiguration causes the new
local outbound policy take effect without resetting the BGP session. As a new set of updates is sent
during outbound policy reconfiguration, a new inbound policy of the neighbor can also take effect.
In order to generate new inbound updates without resetting the BGP session, the local BGP speaker
should store all the received updates without modification, regardless of whether it is accepted or
denied by the current inbound policy. This is memory intensive and should be avoided. On the other
hand, outbound soft reconfiguration does not have any memory overhead. One could trigger
anoutbound reconfiguration in the other side of the BGP session to make the new inbound policy take
effect.
Command
IP address of neighbor
Permit announcement of default route to neighbor
Specify a BGP neighor's AS
Autonomous system number of remote neighbor
Set the neighbor to passive
Model Name
Specifies a BGP neighbor.
- 248 -
Purpose