Introduction
Aggregate network is not advertised.
Core Issue
The most common reason for this problem is a more specific route(s) of the aggregate not existing in the Border Gateway Protocol (BGP) table. This can be seen by looking for more specific prefixes in the BGP table by issuing the the show ip bgp {prefix mask} longer command. The prefix mask entered would be the aggregate route and the mask pair that is being generated.
Resolution
In order to generate and advertise an aggregate route, a more specific route must exist in the BGP table. To accomplish this, perform one of these steps:
- Generate the more specific route by issuing the network command under the router BGP configuration.
- Redistribute a static route for the more specific route under the router BGP configuration.
- Receive the more specific route from the BGP peer.
More Information
show ip bgp
To display entries in the Border Gateway Protocol (BGP) routing table, use the show ip bgp command in user EXEC or privileged EXEC mode.
show ip bgp [ ip-address [ mask [ longer-prefixes [injected] | shorter-prefixes [length] | bestpath | multipaths | subnets ] | bestpath | multipaths ] | all | oer-paths | prefix-list name | pending-prefixes | route-map name ]
Syntax Description
ip-address | (Optional) IP address entered to filter the output to display only a particular host or network in the BGP routing table. |
mask | (Optional) Mask to filter or match hosts that are part of the specified network. |
longer-prefixes | (Optional) Displays the specified route and all more-specific routes. |
injected | (Optional) Displays more specific prefixes injected into the BGP routing table. |
shorter-prefixes | (Optional) Displays the specified route and all less-specific routes. |
length | (Optional) The prefix length. The range is a number from 0 to 32. |
bestpath | (Optional) Displays the best path for this prefix. |
multipaths | (Optional) Displays multipaths for this prefix. |
subnets | (Optional) Displays the subnet routes for the specified prefix. |
all | (Optional) Displays all address family information in the BGP routing table. |
oer-paths | (Optional) Displays Optimized Edge Routing (OER) controlled prefixes in the BGP routing table. |
prefix-list name | (Optional) Filters the output based on the specified prefix list. |
pending-prefixes | (Optional) Displays prefixes that are pending deletion from the BGP routing table. |
route-map name | (Optional) Filters the output based on the specified route map. |
network (BGP and multiprotocol BGP)
To specify the networks to be advertised by the Border Gateway Protocol (BGP) and multiprotocol BGP routing processes, use the network command in address family or router configuration mode. To remove an entry from the routing table, use the no form of this command.
network { network-number [ mask network-mask ] | nsap-prefix } [ route-map map-tag ]
no network { network-number [ mask network-mask ] | nsap-prefix } [ route-map map-tag ]
Syntax Description
network-number | Network that BGP or multiprotocol BGP will advertise. |
masknetwork-mask | (Optional) Network or subnetwork mask with mask address. |
nsap-prefix | Network service access point (NSAP) prefix of the Connectionless Network Service (CLNS) network that BGP or multiprotocol BGP will advertise. This argument is used only under NSAP address family configuration mode. |
route-mapmap-tag | (Optional) Identifier of a configured route map. The route map should be examined to filter the networks to be advertised. If not specified, all networks are advertised. If the keyword is specified, but no route map tags are listed, no networks will be advertised. |
Reference
