Scenario:
The imperial museum corporation has many museums around the world. All networks are connected and BGP is used as the routing protocol. One of the autonomous systems is a transit AS and has two autonomous systems behind it with private AS numbers. You want to ensure that nobody sees those private AS numbers without having trouble with reachability.
Goal:
- All IP addresses have been preconfigured for you.
- Configure EBGP between AS 1 and AS 2.
- Configure EBGP between AS 2 and AS 65503.
- Configure EBGP between AS 2 and AS 65504.
- Advertise the loopback0 interfaces on router Kaiser and Caesar.
- Ensure AS 1 doesn’t see the private AS numbers but has connectivity to network 3.3.3.0 /24 and 4.4.4.0 /24.
IOS:
c3640-jk9s-mz.124-16.bin
Topology:
Video Solution:
Configuration Files
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Written by René Molenaar - CCIE #41726
good lab
thot this was good reading:
http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13756-32.html
really interesting that apparently “remove-private-as” only works with contiguous BGP private AS paths… it does not work with co-mingled/mixed public & private AS numbers.
“If the AS_PATH includes both private and public AS numbers, BGP doesn’t remove the private AS numbers. This situation is considered a configuration error.”
added router “Nero” in AS 5 off of router Caesar (AS 65504)… “remove-private-as” still works for Kaiser & Caesar AS paths but not for Nero:
Emperor#sh ip bgp | b Net
Network Next Hop Metric LocPrf Weight Path
*> 3.3.3.0/24 192.168.12.2 0 2 i
*> 4.4.4.0/24 192.168.12.2 0 2 i
*> 5.5.5.0/24 192.168.12.2 0 2 65504 5 i
kool 🙂
Thanks mate! Nice stuff indeed! Thanks for sharing!