BGP route appearing as *d on remote site

arohilla1978 · ‎11-10-2008

Hi

I have the following setup

Router-A ----ISP IP VN CLOUD ---- Router B

Now i have configured Natting on Router A for a local subnet to subnet range 10.16.22.16/29 and created a loopback interface on Router A having ip from subnet 10.16.22.16/29(this is done bcz i need to publish this range to remote end Router B through BGP which i am accessing through ISP and on the same range i am natting on the local router i.e. Router-A). Now at the Router B my customer sees route for 10.16.22.16/29 in bgp table as *d, so this subnet is not reachable from Router B, now please help me out why this is happening, is ISP dampenning this route or some other problem.

Thnaks in advance

Giuseppe Larosa · ‎11-10-2008

Hello Ashish,

if the ISP was dampening the route that route wouldn't appear on RB BGP table.

It is rather RB that is configured for dampening and has placed in D state the route

see

Damp state-In this state, the route has flapped so often that the router will not advertise this route to BGP neighbors

http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfbgp.html#wp1002403

Hope to help

Giuseppe

arohilla1978 · ‎11-10-2008

Hello Giuseppe

I contacted ISP and he is able to ping my NAT subnet from his PE router which is connected to CE router of customer, means he is seeing that subnet in BGP table with a valid path, i will contact the customer for getting his router details but its very strange that this subnet is installed in ISP VRF and not reaching rather dampped at customer router.

Regards

mohindersingh · ‎11-11-2008

Hi Ashish,

Actually the dampenging should be happening on router-B end. ISP can see the route and it is installing that route in its BGP table as well as it is passing the route to router-B as well but if dampening is configured on router-B and route flapped, route will be removed from the table and will be in dampened state.

Mahi

arohilla1978 · ‎11-11-2008

Dear Mahi

Issue is resolved now, i dont know whether customer did something or it was done from ISP end, but whatever i have read in books and got to know from other people who are working in ISPs that usually ISP do route dampening so as to restrict route flapping to be passed from their customer to internet and other AS.

Anyhow thanks to everybody who participated with the intentions to help resolving this issue.

Thanks and Regards