BGP dmzlink-bw command

snarayanaraju · ‎08-15-2009

Hi Experts,

I trying to configure BGP dmzlink-bw. While doing that i confused in one basic concept. Please help me out. Please find the attachment.

In "show ip bgp" it showing best path to network (in another AS)as "192.168.47.4". In "show ip route" also it is showing both "192.168.67.5" and "192.168.67.5" as multipath is enabled in BGP process.

But when I see "show ip route 10.10.10.0" the * is appearing in "192.168.67.5".

Why it behaves like this. What is the actual concept. I initially thought it is due to "dmzlink-bw". But the condition is same even after removing "dmzlink-bw".

thanks in advance

sairam

Laurent Aubert · ‎08-15-2009

Hi Sairam,

The two routes will be installed even if dmzlink-bw is not configured because R7 received the same update which have the same attributes (weight to NH IGP metric)from two different neighbors.

http://www.cisco.com/en/US/docs/ios/iproute/configuration/guide/irp_bgp_multi_load_ps6441_TSD_Products_Configuration_Guide_Chapter.html

CEF load-balancing per session is used by default.

http://www.cisco.com/en/US/tech/tk827/tk831/technologies_tech_note09186a0080094806.shtml

The * represent the output interface selected by the router for packets handled at the process level which send them on a round robin way.

If you want to see where cef swithced packets are going you should turn on "ip cef accounting per pre load" and then do "sh ip cef internal" and look at the hash buckets. Please refer to the link described above for more details

HTH

Laurent.