3Com 7700 Configuration Manual page 140

132 C 5: R P
HAPTER OUTING
O
ROTOCOL PERATION
Defining the AS Path List The routing information packet of the BGP includes
an AS path domain. The AS path-list can be used to match with the AS path
domain of the BGP routing information to filter the routing information, which
does not conform to the requirements. For the same list number, the user can
define multiple pieces of an AS path-list. Each AS path list is identified with digit.
Please perform the following configurations in the system view.
Table 117 Defining the AS Path List
Operation
Define the AS path list
Delete the specified AS list
By default, no AS path list is defined.
During matching, the relationship of "OR" is available between the members
(acl-number) of the ACLs, so that when the routing information passes through
one piece of this group of lists, it means that the routing information has been
filtered by this group of as-path lists identified with this list number.
Defining Route Policy For information, see "Define a Route Policy".
Defining Match Principle For more information, see "Define If-match Clauses
for a Route Policy".
Define Evaluation Rules For more information, see "Define Apply Clauses for
a Route Policy".
Configuring BGP Route Filtering
Configure BGP to Filter the Received Route Information Perform the
following configurations in BGP view.
The routes received by the BGP can be filtered, and only those routes that meet
the certain conditions will be received by the BGP.
Table 118 Configure Imported Route Filtering
Operation
Configure received route filtering
Cancel the received route filtering
For details, see "Configuring Filtering for the Received Routes".
Configuring Filters on the Routes Distributed by the BGP The routes
distributed by the BGP can be filtered, and only those routes, which meet the
certain conditions, will be distributed by the BGP.
Command
ip as-path acl acl-number { permit | deny }
as-regular-expression
undo ip as-path acl acl-number
Command
filter-policy { acl-number | ip-prefix ip-prefix-name [
gateway ip-prefix-name ] } import
undo filter-policy { acl-number | ip-prefix
ip-prefix-name [ gateway ip-prefix-name ] } import