cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
309
Views
0
Helpful
2
Replies
Highlighted
Beginner

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

2 REPLIES 2
Highlighted
Beginner

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

Highlighted

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.

 

Content for Community-Ad