BGP Commands
©2008 Allied Telesis Inc. All rights reserved.
Software Version 5.2.1
AlliedWare Plus
TM
Operating System Software Reference C613-50003-00 REV E
31.5
aggregate-address
This command enables the BGP aggregate entries. By default this feature is disabled.
Aggregates are used to minimize the size of routing tables. Aggregation combines the
characteristics of several different routes and advertises a single route. This command creates
an aggregate entry in the BGP routing table if any more-specific BGP routes are available in the
specified range. Using the
summary-only
parameter advertises the prefix only, suppressing
the more-specific routes to all neighbors. In the following example Router1 will propagate
network 172.0.0.0 and suppresses the more specific route 172.10.0.0.
Router1#aggregate-address 172.0.0.0/ 8 summary-only
The
as-set
parameter creates an aggregate entry advertising the path for this route, consisting
of all elements contained in all paths being summarized. Use the
as-set
parameter to reduce
the size of path information by listing the AS number only once, even if it was included in
multiple paths that were aggregated. The
as-set
parameter is useful when aggregation of
information results in an incomplete path information. In the following configuration Router1
has set the
as-set
parameter. When sending aggregate information to Router2 this indicates
that 172.0.0.0 belongs to a set 100 and 200. Without the
as-set
parameter Router2 would
receive path information indicating that the information was originating from AS 300 and have
no knowledge that it was coming from two different autonomous systems. This might create
loops.
Router1#
router bgp 300
neighbor 2.2.2.2 remote-as 100
neighbor 3.3.3.3 remote-as 200
aggregate-address 172.0.0.0/8 summary-only as-set
The
no
form disables the BGP aggregate entries.
Syntax
aggregate-address <
ipaddr/m>
{summary-only|as-set}
no aggregate-address <
ipaddr/m>
{summary-only|as-set}
Mode
Router mode
Examples
Related Commands
match as-path
Parameter
Description
<
ipaddr/m>
Specifies the aggregate IPv4 address and mask.
summary-only
Filters more specific routes from updates.
as-set
Generates AS set path information
awplus#
configure terminal
awplus(config)#
router bgp 100
awplus(config-router)#
aggregate-address 10.0.0.0/8 as-set
summary-only