(AS200)
AS100 AS222 AS300
+----+ +----+ +----+
| | | | | |
| R1 +---+ R2 +---+ R3 |
| | | | | |
+----+ +----+ +----+
100.0.0.0/24 130.0.0.0/24
local-as
R2(config-router)#do sh run | s local-as
neighbor 10.0.0.1 local-as 200
R1#sh ip bgp | b Net
Network Next Hop Metric LocPrf Weight Path
*> 100.0.0.0/24 0.0.0.0 0 32768 i
*> 130.0.0.0/24 10.0.0.2 0 200 222 300 i
R2(config-router)#do sh ip bgp | b Net
Network Next Hop Metric LocPrf Weight Path
*> 100.0.0.0/24 10.0.0.1 0 0 200 100 i
*> 130.0.0.0/24 10.0.0.6 0 0 300 i
R3#sh ip bgp | b Net
Network Next Hop Metric LocPrf Weight Path
*> 100.0.0.0/24 10.0.0.5 0 222 200 100 i
*> 130.0.0.0/24 0.0.0.0 0 32768 i
local-as no-prepend
R2(config-router)#do sh run | s local-as
neighbor 10.0.0.1 local-as 200 no-prepend
R1#sh ip bgp | b Net
Network Next Hop Metric LocPrf Weight Path
*> 100.0.0.0/24 0.0.0.0 0 32768 i
*> 130.0.0.0/24 10.0.0.2 0 200 222 300 i
R2(config-router)#do sh ip bgp | b Net
Network Next Hop Metric LocPrf Weight Path
*> 100.0.0.0/24 10.0.0.1 0 0 100 i
*> 130.0.0.0/24 10.0.0.6 0 0 300 i
R3#sh ip bgp | b Net
Network Next Hop Metric LocPrf Weight Path
*> 100.0.0.0/24 10.0.0.5 0 222 100 i
*> 130.0.0.0/24 0.0.0.0 0 32768 i
local-as no-prepend replace-as
R2(config-router)#do sh run | s local-as
neighbor 10.0.0.1 local-as 200 no-prepend replace-as
R1#sh ip bgp | b Net
Network Next Hop Metric LocPrf Weight Path
*> 100.0.0.0/24 0.0.0.0 0 32768 i
*> 130.0.0.0/24 10.0.0.2 0 200 300 i
R2(config-router)#do sh ip bgp | b Net
Network Next Hop Metric LocPrf Weight Path
*> 100.0.0.0/24 10.0.0.1 0 0 100 i
*> 130.0.0.0/24 10.0.0.6 0 0 300 i
R3#sh ip bgp | b Net
Network Next Hop Metric LocPrf Weight Path
*> 100.0.0.0/24 10.0.0.5 0 222 100 i
*> 130.0.0.0/24 0.0.0.0 0 32768 i
dual-as
R2(config-router)#neighbor 10.0.0.1 local-as 200 no-prepend replace-as ?
dual-as Accept either real AS or local AS from the ebgp peer