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

conflicting route

Hi. Have a problem with cisco ASR1002 IOS XE Version: 03.08.01.S.

Have a bgp instance, and bestpath to destination 195.239.213.1 from 217.150.54.30, but "ip route" output shows me a different way. I can not understand, why?

 

asr#sh ip bgp 195.239.213.1  bestpath
BGP routing table entry for 195.239.0.0/16, version 273643622
BGP Bestpath: deterministic-med
Paths: (4 available, best #3, table default)
  Not advertised to any peer
  Refresh Epoch 1
  20485 3216, (received & used)
    217.150.54.30 from 217.150.54.30 (10.77.0.46)
      Origin IGP, localpref 100, valid, external, best
      Community: 20485:40399
      rx pathid: 0, tx pathid: 0x0

 

asr#sh ip bgp 195.239.213.1 255.255.255.0
% Network not in table

 

asr#sh ip route 195.239.213.1
Routing entry for 195.239.213.0/24
  Known via "bgp 11111", distance 180, metric 0
  Tag 47328, type external
  Last update from 193.106.112.91 2w1d ago
  Routing Descriptor Blocks:
  * 193.106.112.91, from 193.106.112.1, 2w1d ago
      Route metric is 0, traffic share count is 1
      AS Hops 4
      Route tag 47328
      MPLS label: none

In other words, the route 195.239.213.0/24 is not in the bgp table, but is still on the "ip route" table

Everyone's tags (3)
2 REPLIES
New Member

Can you share the output of

Can you share the output of sh ip bgp 195.239.213.1 without mentioning the subnet musk?

It seems your bestpath is showing route for 195.239.0.0/16 and the AS numbers are also not matching for Routing entry for 195.239.213.0/24

New Member

Hi, thx for replay. I have a

Hi, thx for replay. I have a Ticket for this subnet, and i enters the command clear ip route 195.239.213.1 255.255.255.0 without waiting for reply. And now i have this:

 

asr#sh ip bgp 195.239.213.1 (Output the same as was)
BGP routing table entry for 195.239.0.0/16, version 273643622
BGP Bestpath: deterministic-med
Paths: (5 available, best #4, table default)
  Not advertised to any peer
  Refresh Epoch 1
  31133 3216, (received & used)
    78.25.66.237 from 78.25.66.237 (10.63.0.99)
      Origin IGP, localpref 100, valid, external
      rx pathid: 0, tx pathid: 0
  Refresh Epoch 1
  20764 3216, (received & used)
    193.106.112.103 from 193.106.112.1 (193.106.112.1)
      Origin IGP, metric 0, localpref 100, valid, external
      Community: 3216:2001 3216:4100 20764:3006 20764:3011 20764:3021 20764:3026 50384:1010 50384:2050 50384:3016 50384:4001
      rx pathid: 0, tx pathid: 0
  Refresh Epoch 1
  20764 3216, (received & used)
    193.106.112.103 from 193.106.112.2 (193.106.112.2)
      Origin IGP, metric 0, localpref 100, valid, external
      Community: 3216:2001 3216:4100 20764:3006 20764:3011 20764:3021 20764:3026 50384:1010 50384:2050 50384:3016 50384:4001
      rx pathid: 0, tx pathid: 0
  Refresh Epoch 1
  20485 3216, (received & used)
    217.150.54.30 from 217.150.54.30 (10.77.0.46)
      Origin IGP, localpref 100, valid, external, best
      Community: 20485:40399
      rx pathid: 0, tx pathid: 0x0
  Refresh Epoch 1
  9002 3216, (received & used)
    87.245.229.97 from 87.245.229.97 (87.245.225.2)
      Origin IGP, localpref 100, valid, external
      Community: 9002:9002 9002:64667
      rx pathid: 0, tx pathid: 0

asr#sh ip route 195.239.213.1 (but this output changes:)
Routing entry for 195.239.0.0/16, supernet
  Known via "bgp 11111", distance 180, metric 0
  Tag 20485, type external
  Last update from 217.150.54.30 1w0d ago
  Routing Descriptor Blocks:
  * 217.150.54.30, from 217.150.54.30, 1w0d ago
      Route metric is 0, traffic share count is 1
      AS Hops 2
      Route tag 20485
      MPLS label: none

 

Interesting, but much routes have dead gw (193.106.112.91). It does anonce nothing. But routes are still in sh ip route table

asr# sh ip route | i 193.106.112.91
B        31.207.128.0/18 [180/0] via 193.106.112.91, 2w2d
B        31.207.192.0/18 [180/0] via 193.106.112.91, 2w2d
B        42.96.192.0/19 [180/0] via 193.106.112.91, 2w2d
<CUT>

asr#sh ip bgp 31.207.128.0/18
% Network not in table

asr#sh ip bgp 31.207.192.0/18
% Network not in table

asr#sh ip route 31.207.192.0
Routing entry for 31.207.192.0/18
  Known via "bgp 11111", distance 180, metric 0
  Tag 47328, type external
  Last update from 193.106.112.91 2w3d ago
  Routing Descriptor Blocks:
  * 193.106.112.91, from 193.106.112.1, 2w3d ago
      Route metric is 0, traffic share count is 1
      AS Hops 4
      Route tag 47328
      MPLS label: none

Seems like asr think that route have a greater netmask, and does not delete route from "ip route" table, even if neighbor doesn't announce network anymore. I plan to downgrade ios. Because this behavior, in my opinion, is not normal.

 

173
Views
0
Helpful
2
Replies
CreatePlease login to create content