- Allows the advertising/originating of major networks into BGP
- If no mask option, a classful subnet would be assumed
- If Auto-Summary is ENABLED: At least one subnet of the major network is required in the RIB before the route is originated in BGP
- If Auto-Summary is DISABLED: A exact route match is required in the RIB before the route is originated in BGP
- Route-Map option - Allows network parameters to be modified before they are entered into the BGP table
- BGP routes originated through "network" command have a origin code of 'i-igp'
network {major-network} [mask {net}] [route-map {name}]
2. Redistribution
- BGP routes originated through redistribution have a origin code of '?-incomplete'
access-list {number} permit {network}
redistribute {igp} [pid] [metric] [route-map] - Redistributes local static or connected routes into BGP table
redistribute {static|connected} [route-map] [metric]
3. Aggregation
- Specifies a aggregation range in BGP routing process.
- Default = more specific routes are sent
- The aggregate will be announced only if there is at least one network in the specified range in the BGP table (not the IGP table)
- Summary-only: Advertises only the aggregate and not the individual networks
- Routes originated with aggregate command has origin code of "i"
aggregate-address {aggregate} [mask] [summary-only]
- Specifies a suppress map to be referenced
- The prefixes within the aggregate, permitted/matched by the route-map will be suppressed from being advertised to neighbors
aggregate-address {aggregate} {mask} suppress-map {route-map} [summary-only]
- Specifies what routes to unsuppress on a per neighbor basis
neighbor {ip} unsuppress-map {route-map}
- Displays the configured filter lists
sh ip as-path-access-list [filter-list]
- Displays all routes permitted by the specified AS-path access-list
sh ip bgp filter-list {access-list-number}
- Displays all routes matching regular-expression in one or all filter-lists
sh ip bgp regexp {expression}
- Displays the prefix-list and the sequence numbers
sh ip prefix-list {list}[det|sum][longer]
sh ip bgp prefix-list {list-name}
- Configures an AS-path filter list
ip as-path access-list {1-199} [permit/deny] {regex}
- Configures a prefix-list, if [ge/le] is not defined, prefix is matched exactly
- [ge] Means greater than AND equals to
- [le] Means less than AND equals to
ip prefix-list {name} [seq] [permit|deny] {prefix} [ge] [le]
- Configures inbound/outbound AS-path filter for specific BGP neighbor
router bgp {asn}
neighbor {ip} filter-list {as-path-list} [in|out]- Applies filters for inbound/outbound BGP routing updates for a neighbor
neighbor {ip | peer-group} prefix-list list [in|out]
- Filters routes redistributed from specified routing process (into|outof) BGP distribute-list prefix-list {prefix-list} {in|out} {routing-process}
1. >> Matches all hosts routes
ip prefix-list A permit 0.0.0.0/0 ge 32
2. >> Any subnets in class A address space. (/1: 1st bit(0) can’t change)
ip prefix-list B permit 0.0.0.0/1 ge 9
3. >> Any subnets in class B address space. (/2: 1st 2 bits(10) can’t change)
ip prefix-list C permit 128.0.0.0/2 ge 17
4. >> Any subnets in class C address space. (/3: 1st 3 bits(110) can’t change)
ip prefix-list D permit 192.0.0.0/3 ge 24
5. >> Match any/all routes
ip prefix-list E permit 0.0.0.0/0 le 32
6. >> Match just the default route
ip prefix-list F permit 0.0.0.0/0
7. >> Matches any prefix in class A address space with more than 256 addresses
ip prefix-list G permit 0.0.0.0/1 le 24
8. >> Matches only a 10.0.0.0/8 route (no more, no less)
ip prefix-list H permit 10.0.0.0/8
9. >> Matches any route in the RFC-1918 pvt 10/8 range, (including 10.1.2.0/24)
ip prefix-list I permit 10.0.0.0/8 le 32
ip prefix-list J permit 172.16.0.0/12 le 32
11. >> Matches any route in the RFC-1918 pvt 192.168.0.0/16 range
ip prefix-list K permit 192.168.0.0/16 le 32
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