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Command or Action |
Purpose |
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enable
Example:
Device> enable
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Enables privileged EXEC mode.
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Enter your password if prompted.
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configure terminal
Example:
Device# configure terminal
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Enters global configuration mode. |
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router bgp autonomous-system-number
Example:
Device(config)# router bgp 45000
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Enters router configuration mode and creates a BGP routing process. |
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address-family ipv4 [unicast | multicast| vrf vrf-name]
Example:
Device(config-router)# address-family ipv4 unicast
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Specifies the IPv4 address family and enters address family configuration mode.
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The unicast keyword specifies the IPv4 unicast address family. By default, the router is placed in address family configuration mode for the IPv4 unicast address family if the unicast keyword is not specified with the address-family ipv4 command.
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The multicast keyword specifies IPv4 multicast address prefixes.
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The vrf keyword and vrf-name argument specify the name of the VRF instance to associate with subsequent IPv4 address family configuration mode commands.
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bgp nexthop route-map map-name
Example:
Device(config-router-af)# bgp nexthop route-map CHECK-NEXTHOP
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Permits a route map to selectively define routes to help resolve the BGP next hop.
-
In this example the route map named CHECK-NEXTHOP is created.
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exit
Example:
Device(config-router-af)# exit
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Exits address family configuration mode and enters router configuration mode. |
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exit
Example:
Device(config-router)# exit
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Exits router configuration mode and enters global configuration mode. |
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ip prefix-list list-name [seq seq-value] {deny network / length | permit network/length} [ge ge-value] [le le-value]
Example:
Device(config)# ip prefix-list FILTER25 seq 5 permit 0.0.0.0/0 le 25
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Creates a prefix list for BGP next-hop route filtering.
-
Selective next-hop route filtering supports prefix length matching or source protocol matching on a per address-family basis.
-
The example creates a prefix list named FILTER25 that permits routes only if the mask length is more than 25; this will avoid aggregate routes being considered as the next-hop route.
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route-map map-name [permit | deny] [sequence-number]
Example:
Device(config)# route-map CHECK-NEXTHOP deny 10
|
Configures a route map and enters route map configuration mode.
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In this example, a route map named CHECK-NEXTHOP is created. If there is an IP address match in the following match command, the IP address will be denied.
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match ip address prefix-list prefix-list-name [prefix-list-name...]
Example:
Device(config-route-map)# match ip address prefix-list FILTER25
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Matches the IP addresses in the specified prefix list.
-
Use the prefix-list-name argument to specify the name of a prefix list. The ellipsis means that more than one prefix list can be specified.
Note |
Only the syntax applicable to this task is used in this example. For more details, see the Cisco IOS IP Routing: BGP Command Reference. |
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exit
Example:
Device(config-route-map)# exit
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Exits route map configuration mode and enters global configuration mode. |
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route-map map-name [permit | deny] [sequence-number]
Example:
Device(config)# route-map CHECK-NEXTHOP permit 20
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Configures a route map and enters route map configuration mode.
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In this example, all other IP addresses are permitted by route map CHECK-NEXTHOP.
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end
Example:
Device(config-route-map)# end
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Exits route map configuration mode and enters privileged EXEC mode. |
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show ip bgp [network] [network-mask]
Example:
Device# show ip bgp
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Displays the entries in the BGP routing table.
-
Enter this command to view the next-hop addresses for each route.
Note |
Only the syntax applicable to this task is used in this example. For more details, see the Cisco IOS IP Routing: BGP Command Reference. |
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