3Com S7906E Configuration Manual page 1418

To do...
Apply a filter policy to routes
received
Configure to permit the routes
with their AS numbers
contained in their AS_PATH
attributes being the local AS
number (this operation can also
specify the number of the AS
number occurrences allowed)
AS number contained in the AS_PATH attribute can be used for route loop detect. With EBGP running
between a MCE and a site, the routes advertised by an MCE device to the site carry the local AS
number. So do the routes advertised by the site. In this case, you need to configure to permit the routes
with their AS numbers contained in their AS_PATH attributes being the local AS number on MCE
devices for the routes advertised by the site to be received and processed by the MCE device.
2) Configuration on the site
The site configuration procedures vary with device model. The following takes an S7900E Ethernet
switch as an example. As for switches from other vendors, refer to the corresponding user manuals.
Follow these steps to configure the site:
To do...
Enter system view
Enter BGP view
Configure the PE as a peer
Configure to import routes
Use the command...
filter-policy { acl-number |
ip-prefix ip-prefix-name }
import
peer { group-name |
ip-address } allow-as-loop
[ number ]
Use the command...
system-view
bgp as-number
peer { group-name | ip-address }
as-number as-number
import-route protocol
[ process-id ] [ med med-value |
route-policy route-policy-name ]
*
2-7
Remarks
Optional
By default, received routes are
not filtered.
Optional
By default, routes with their AS
numbers contained in their
AS_PATH attributes being the
local AS number are denied.
Remarks
—
—
Required
Optional
The site must advertise the
addresses of the reachable
VPN segments to the MCE
connected to the site.