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Cisco Nexus 3548 Switch NX-OS Unicast Routing Command Reference
OL-27852-01
Chapter Unicast Routing Commands
aggregate-address (BGP)
Using the
as-set
keyword creates an aggregate entry using the same rules that the command follows
without this keyword, but the path advertised for this route will be an AS_SET consisting of all elements
contained in all paths that are being summarized. Do not use this form of the
aggregate-address
command when aggregating many paths, because this route must be continually withdrawn and updated
as autonomous system path reachability information for the summarized routes changes.
Using the
summary-only
keyword not only creates the aggregate route (for example, 192.*.*.*) but also
suppresses advertisements of more-specific routes to all neighbors. If you want to suppress only
advertisements to certain neighbors, you may use the
neighbor distribute-list
command, with caution.
If a more-specific route leaks out, all BGP routers will prefer that route over the less-specific aggregate
you are generating (using longest-match routing).
Using the
suppress-map
keyword creates the aggregate route but suppresses advertisement of specified
routes. You can use the match clauses of route maps to selectively suppress some more-specific routes
of the aggregate and leave others unsuppressed. IP access lists and autonomous system path access lists
match clauses are supported.
Using the
advertise-map
keyword selects specific routes that will be used to build different components
of the aggregate route, such as AS_SET or community. This form of the
aggregate-address
command
is useful when the components of an aggregate are in separate autonomous systems and you want to
create an aggregate with AS_SET, and advertise it back to some of the same autonomous systems. You
must remember to omit the specific autonomous system numbers from the AS_SET to prevent the
aggregate from being dropped by the BGP loop detection mechanism at the receiving router. IP access
lists and autonomous system path access lists match clauses are supported.
Using the
attribute-map
keyword allows attributes of the aggregate route to be changed. This form of
the
aggregate-address
command is useful when one of the routes forming the AS_SET is configured
with an attribute such as the community no-export attribute, which would prevent the aggregate route
from being exported. An attribute map route map can be created to change the aggregate attributes.
This command requires the LAN Enterprise Services license.
Examples
AS-Set Example
This example shows how to create an aggregate BGP address in router configuration mode. The path
advertised for this route will be an AS_SET consisting of all elements contained in all paths that are
being summarized.
switch#
configure terminal
switch(config)#
router bgp 64496
switch(config-router)#
aggregate-address 10.0.0.0 255.0.0.0 as-set
switch(config-router)#
Summary-Only Example
This example shows how to create an aggregate BGP address in address family configuration mode and
apply it to the multicast database (SAFI) under the IP Version 4 address family. Because the
summary-only
keyword is configured, more-specific routes are filtered from updates.
switch#
configure terminal
switch(config)#
router bgp 64496
switch(config-router)#
address-family ipv4 multicast
switch(config-router-af)#
aggregate-address 10.0.0.0 255.0.0.0 summary-only
switch(config-router-af)#
