BGP and RIB

[mguzman4158]

Hello,

Scenario:

Two data centers (Data Center A and B) in different states. 

Company X owns x.x.1.0/24 and x.x.2.0/24 AS:1234

Data center A gets the full routing table for ISP1 and advertises x.x.1.0/24 

Data center B gets DF only from ISP2 and advertises x.x.2.0/24

Issue:

Data center A is not getting x.x.2.0/24 from ISP2.   ISP2 does advertise x.x.2.0/24 but Company’s bgp peering router doesn’t see a route for x.x.2.0/24

ISP2 is sending x.x.2.0/route like this

  Prefix                  Nexthop              MED     Lclpref    AS path

* x.x.2.0/24         Self                                    444 555 1234 I

Question?

Is the reason why the wan rt peering with ISP2 not seeing the route to x.x.2.0/24 because it sees its own AS number in the AS-path?  

Thank you in advance for your input.  

Cheers! 

[mguzman4158]

Clarification TYPO!!! 

Issue:

Data center A is not getting x.x.2.0/24 from ISP1.   ISP1 does advertise x.x.2.0/24 but Company’s bgp peering router doesn’t see a route for x.x.2.0/24

ISP1 is sending x.x.2.0/route like this

  Prefix                  Nexthop              MED     Lclpref    AS path

* x.x.2.0/24         Self                                    444 555 1234 I

Thank you! 

[Joseph Nelson · Accepted solution]

Hi,

You are correct. In this scenario, DC-A should see x.x.2.0/24 from ISP1, however, it should be dropped from its BGP RIB on receipt due to as-path attribute.

This is normal operation of BGP.