Disabling the BGP AS_PATH check function
A device can be congured so that the AS_PATH check function for routes learned from a specic location is disabled, and routes that
contain the recipient BGP speaker's AS number are not rejected.
1. Enter the congure terminal command to access global conguration mode.
device# configure terminal
2. Enter the router bgp command to enable BGP routing.
device(config)# router bgp
3. Enter the address-family command and specify the ipv6 and unicast keywords to enter IPv6 address family
conguration
mode.
device(config-bgp-router)# address-family ipv6 unicast
4. Enter the neighbor ipv6-address allowas-in command and specify a number to disable the BGP AS_PATH check function,
and specify the number of times that the AS path of a received route may contain the recipient BGP speaker's AS number and
still be accepted.
device(config-bgp-ipv6u)# neighbor 2001:db8:e0ff:783a::4 allowas-in 3
This example species that the AS path of a received route may contain the recipient BGP speaker's AS number three times and still be
accepted.
device# configure terminal
device(config)# router bgp
device(config-bgp-router)# address-family ipv6 unicast
device(config-bgp-ipv6u)# neighbor 2001:db8:e0ff:783a::4 allowas-in 3
Displaying BGP4+ statistics
Various show ipv6 bgp commands verify information about BGP4+
congurations.
Use one or more of the following commands to verify BGP4+ information. The commands do not have to be entered in this order.
1. Enter the show ipv6 bgp summary command.
device# show ipv6 bgp summary
BGP4 Summary
Router ID: 122.122.122.122 Local AS Number: 122
Confederation Identifier: not configured
Confederation Peers:
Cluster ID: 122
Maximum Number of IP ECMP Paths Supported for Load Sharing: 1
Number of Neighbors Configured: 20, UP: 15
Number of Routes Installed: 219, Uses 20805 bytes
Number of Routes Advertising to All Neighbors: 2802 (440 entries), Uses 26400 bytes
Number of Attribute Entries Installed: 31, Uses 2852 bytes
Neighbor Address AS# State Time Rt:Accepted Filtered Sent ToSend
2001:54:54::54 122 ESTAB 0h19m58s 0 0 146 0
2001:55:55::55 122 ESTAB 0h19m54s 1 0 146 0
2001:122:53::53 6000 ESTAB 0h22m39s 50 0 147 0
2001:122:534:2::534
534 ESTAB 0h 3m20s 10 0 137 0
2001:125:125::125 122 CONN 0h11m33s 0 0 0 -
This example output gives summarized BGP4+ information.
Conguring BGP4+
FastIron Ethernet Switch Layer 3 Routing
500 53-1003627-04