Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Weird BGP path selection problem

Hi, all,

I am seeing a weird BGP path selection problem on 4948 switch running cat4500-entservicesk9-mz.122-46.SG.bin code, this switch has two uplinks to the same ISP's different edge router, one circuit is primary the other one is strict backup, only default route is accepted from ISP. I am setting both local preference and weight to the default route advertised over backup link, however neither one is taking effect, BGP still thinks the backup link is better, what could be wrong?

rtr#sh ip bgp 0.0.0.0/0
BGP routing table entry for 0.0.0.0/0, version 105
Paths: (3 available, best #2, table Default-IP-Routing-Table, not advertised to EBGP peer)
  Not advertised to any peer
  17675, (received & used)
    203.169.8.37 from 203.169.8.37 (61.211.160.150)
      Origin IGP, localpref 100, valid, external
      Community: 65001:0 no-export
  17675
    203.169.8.45 from 203.169.8.45 (61.211.160.151)
      Origin IGP, localpref 90, weight 90, valid, external, best <====
      Community: 65001:0 no-export
  17675, (received-only)
    203.169.8.45 from 203.169.8.45 (61.211.160.151)
      Origin IGP, localpref 100, valid, external
      Community: 65001:0 no-export

 

Thanks

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Hi, On cisco routers , weight

Hi,

 

On cisco routers , weight is having highest preference to decide best path. By default for received route, weight is 0 but you are setting weight 90 to backup path and that is why it is getting preferred (higher is better). Please remove weight and let local preference be 90 (lesser than route on primary path)

 

--Pls dont forget to rate helpful posts--

Regards,

Akash

2 REPLIES
Cisco Employee

Hi, On cisco routers , weight

Hi,

 

On cisco routers , weight is having highest preference to decide best path. By default for received route, weight is 0 but you are setting weight 90 to backup path and that is why it is getting preferred (higher is better). Please remove weight and let local preference be 90 (lesser than route on primary path)

 

--Pls dont forget to rate helpful posts--

Regards,

Akash

New Member

Thanks, somehow I always

Thanks, somehow I always thought default weight is 100, thanks!

40
Views
0
Helpful
2
Replies
CreatePlease login to create content