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Network disruption VSP8600

Network disruption VSP8600

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BRMS
New Contributor II

‎10-06-2020 09:36 AM

I’m using 4 VSP8600 in a SPBM-Configuration. Today we experienced a network disruption although no configuration changes were made. The logs are full of these:

************************************************************************************
		Command Execution Time: Tue Oct 06 11:26:49 2020 CEST
************************************************************************************
1 2020-10-06T11:24:33.770+02:00 kreuz IO4 - 0x00138537 - 0004e001 DYNAMIC CLEAR GlobalRouter COP-SW INFO VIST peer mac b4:2d:56:9c:7a:11 on VID 2422 is learnt on non-IST MltId-1, Pointing record back to IST port.Total Peer Mac Move Count: 8051
1 2020-10-06T11:24:30.533+02:00 kreuz IO2 - 0x00138537 - 0004e001 DYNAMIC CLEAR GlobalRouter COP-SW INFO VIST peer mac b4:2d:56:9c:7a:36 on VID 426 is learnt on non-IST MltId-1, Pointing record back to IST port.Total Peer Mac Move Count: 16644
1 2020-10-06T11:22:35.621+02:00 kreuz IO3 - 0x00138537 - 0004e001 DYNAMIC CLEAR GlobalRouter COP-SW INFO VIST peer mac b4:2d:56:9c:7a:2b on VID 419 is learnt on non-IST MltId-1, Pointing record back to IST port.Total Peer Mac Move Count: 13707

...

1 2020-10-06T10:42:31.049+02:00 kreuz IO5 - 0x00138537 - 0004e001 DYNAMIC CLEAR GlobalRouter COP-SW INFO VIST peer mac b4:2d:56:9c:7a:28 on VID 205 is learnt on non-IST MltId-1, Pointing record back to IST port.Total Peer Mac Move Count: 9389
1 2020-10-06T10:42:31.035+02:00 kreuz IO6 - 0x00138537 - 0004e001 DYNAMIC CLEAR GlobalRouter COP-SW INFO VIST peer mac b4:2d:56:9c:7a:28 on VID 205 is learnt on non-IST MltId-1, Pointing record back to IST port.Total Peer Mac Move Count: 631

...

1 2020-10-06T10:42:22.788+02:00 kreuz CP1 - 0x00004619 - 01900001 DYNAMIC CLEAR GlobalRouter SNMP INFO Smlt Link Up Trap(SmltId=133)
1 2020-10-06T10:42:22.788+02:00 kreuz CP1 - 0x0000000a - 01900001.133 DYNAMIC CLEAR GlobalRouter SW INFO SMLT 133 Link is UP
1 2020-10-06T10:42:17.262+02:00 kreuz CP1 - 0x0000461a - 01900001 DYNAMIC SET GlobalRouter SNMP INFO Smlt Link Down Trap(SmltId=133)
1 2020-10-06T10:42:17.261+02:00 kreuz CP1 - 0x00000009 - 01900001.133 DYNAMIC SET GlobalRouter SW INFO SMLT 133 Link is DOWN

...

1 2020-10-06T10:04:03.768+02:00 kreuz IO3 - 0x00138537 - 0004e001 DYNAMIC CLEAR GlobalRouter COP-SW INFO VIST peer mac b4:2d:56:9c:7a:2b on VID 419 is learnt on non-IST MltId-1, Pointing record back to IST port.Total Peer Mac Move Count: 12529
1 2020-10-06T10:03:48.600+02:00 kreuz IO4 - 0x00138537 - 0004e001 DYNAMIC CLEAR GlobalRouter COP-SW INFO VIST peer mac b4:2d:56:9c:7a:11 on VID 2422 is learnt on non-IST MltId-1, Pointing record back to IST port.Total Peer Mac Move Count: 7347

What could be the cause of this problem and how can i debug this any further? my log only goes back for ~1hr

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Miguel-Angel_RO
Valued Contributor II

‎10-06-2020 08:32 PM

brms,

 

I see the following points to be worked out:

  • change the isis metrics of your isis interfaces: the MLT should have the cost of the interfaces 1/1 or 1/5 divided by 2.
    • If it is 10G links: MLT=100, interfaces 1/1,1/5 = 200
  • I would enable SLPP on all the C-VLANs
  • Could you confirm the value of the i-sid used on the different switches for the vIST?
    • It should be uniq per cluster
  • I would change the subnet to /30 but this shouldn’t cause any issue using a /24
  • avoid the redistribution of the vIST subnets in ISIS/OSPF/other: https://gtacknowledge.extremenetworks.com/pkb_mobile#article/How_To/kA12T0000004QhGSAU/s
  • Ensure that you don’t use the vIST subnet for other purposes than VIST (not as next hop, not as SNMP access, etc)

Mig

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Miguel-Angel_RO
Valued Contributor II

‎10-06-2020 11:49 AM

brms,

 

The following info from both IST members is needed to check if a loop is possible on your infra:

show mlt

show isis interface

show isis adja

show slpp

show spanning-tree config

show spanning-tree mstp port role

For the vIST:

show virtual-ist

show vlan members

show i-sid vlan

 

The logs are still present on the flash memory of your VSP. Just connect with sftp or perform an “ls” on the VSP to see them.

The name starts with “log”…

 

As personal advice, in such situation (network disruption) I would open a GTAC case in parallel of my own investigations. There is a lot of info to be grabbed just after the issue.

Regards

Mig

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BRMS
New Contributor II

‎10-06-2020 10:34 AM

as far as i understand the virtual-Ist configuration only consists of a vlan-id and the loopback-ip of the ist peer. mlt 1 is a trunk between the two vIST-peers, so how come the log says its a non-IST MLT?

i’m using loop-detection on all switches that are connected to the vsp. i had this error a few times the last months and after rebooting all 4 vsp it goes away for a few weeks. honestly it feels more like a bug not like a real loop.

is there a way to debug this occurance further? unfortunatly the log doesn’t show me anything from the start of this error because it only covers the last 1-2 hours. is there a way to increase log size?

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Roger_Lapuh
Extreme Employee

‎10-06-2020 09:41 AM

The reason for this message is typically a network loop. The switch detects that it has learnt it’s peers MAC address over a normal or SMLT UNI port and thus is moving the peer-mac back to the vIST where it should it learn it from.

Make sure you protect yourself against loops with the recommended measures such as SLPP and SLPP guard and BPDU guard.

 

Roger 

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