Login | Register For Free | Help
Search for: (Advanced)

Mailing List Archive: Cisco: NSP

unblocking port on 3750

 

 

Cisco nsp RSS feed   Index | Next | Previous | View Threaded


Djamel.Bouazza at tecteo

Aug 2, 2012, 1:42 AM

Post #1 of 5 (2077 views)
Permalink
unblocking port on 3750

Hi expert,

Yesterday we reloaded switch 3750 and when we try to add new vlan we have the following error message:

Aug 2 06:06:22 CET: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking Port-channel4 on VLAN0001. Port consistency restored.

Could you please help to found the root cause.

Version : flash:/c3750e-universalk9-mz.122-55.SE/c3750e-universalk9-mz.122-55.SE.bin"

Thanks in advance

Kind Regards,

Djamel Bouazza
Senior Corporate Network Engineer
IT Departement

Ce message transmis par voie électronique ainsi que toutes ses annexes contiennent des informations qui peuvent être confidentielles ou protégées. Ces informations sont uniquement destinées à l’usage des personnes ou des entités précisées dans les champs ‘A’, ‘Cc’ et ‘Cci’. Si vous n’êtes pas l’un de ces destinataires, soyez conscient que toute forme, partielle ou complète, de divulgation, copie, distribution ou utilisation de ces informations est strictement interdite. Si vous avez reçu ce message par erreur, veuillez nous en informer par téléphone ou par message électronique et détruire les informations immédiatement. Ce message n’engage que son signataire et aucunement son employeur.

_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/


peter at rathlev

Aug 2, 2012, 2:50 AM

Post #2 of 5 (1993 views)
Permalink
Re: unblocking port on 3750 [In reply to]

On Thu, 2012-08-02 at 08:42 +0000, Bouazza Djamel wrote:
> Yesterday we reloaded switch 3750 and when we try to add new vlan we
> have the following error message:
>
> Aug 2 06:06:22 CET: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking Port-channel4 on VLAN0001. Port consistency restored.
>
> Could you please help to found the root cause.

Unblocking is the restoration of correctness following the actual error
which has blocked the port. You should have a previous message saying
why the port was blocked, something like this:

Jul 4 14:56:02.852 CEST: %SPANTREE-2-BLOCK_PVID_PEER: Blocking Port-channel4 on VLAN0001. Inconsistent peer vlan.

Posting the configuration from both Po4 on the device logging the
message and the configuration from the neighboring port-channel would
probably help towards saying what the error could have been.

--
Peter


_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/


Djamel.Bouazza at tecteo

Aug 2, 2012, 3:09 AM

Post #3 of 5 (2005 views)
Permalink
Re: unblocking port on 3750 [In reply to]

Hi Peter,

Thank you for your swift reply. Hereunder the errors messages on switch 3750.
Aug 2 06:06:07 CET: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 2062 on Port-channel4 VLAN1.
Aug 2 06:06:07 CET: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking Port-channel4 on VLAN0001. Inconsistent local vlan.
Aug 2 06:06:22 CET: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking Port-channel4 on VLAN0001. Port consistency restored.

On switch 3750 :
nterface Port-channel4
description *** to CORE SWITCH HP ***
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-999,2010,2014,2026-2055,2060-2067,2069
switchport mode trunk

On Core switch HP 12508

interface Bridge-Aggregation2
description *** to 3750 DATACENTER ***
port link-type trunk
port trunk permit vlan 1 to 255 257 to 999 2010 2014 2027 to 2055 2060 to 2067 2069
link-aggregation mode dynamic

Thank you in advance,

Kind Regards,


Djamel Bouazza
IT Departement



-----Message d'origine-----
De : Peter Rathlev [mailto:peter [at] rathlev]
Envoyé : jeudi 2 août 2012 11:50
À : Bouazza Djamel
Cc : cisco-nsp [at] puck
Objet : Re: [c-nsp] unblocking port on 3750

On Thu, 2012-08-02 at 08:42 +0000, Bouazza Djamel wrote:
> Yesterday we reloaded switch 3750 and when we try to add new vlan we
> have the following error message:
>
> Aug 2 06:06:22 CET: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking Port-channel4 on VLAN0001. Port consistency restored.
>
> Could you please help to found the root cause.

Unblocking is the restoration of correctness following the actual error which has blocked the port. You should have a previous message saying why the port was blocked, something like this:

Jul 4 14:56:02.852 CEST: %SPANTREE-2-BLOCK_PVID_PEER: Blocking Port-channel4 on VLAN0001. Inconsistent peer vlan.

Posting the configuration from both Po4 on the device logging the message and the configuration from the neighboring port-channel would probably help towards saying what the error could have been.

--
Peter


Ce message transmis par voie électronique ainsi que toutes ses annexes contiennent des informations qui peuvent être confidentielles ou protégées. Ces informations sont uniquement destinées à l’usage des personnes ou des entités précisées dans les champs ‘A’, ‘Cc’ et ‘Cci’. Si vous n’êtes pas l’un de ces destinataires, soyez conscient que toute forme, partielle ou complète, de divulgation, copie, distribution ou utilisation de ces informations est strictement interdite. Si vous avez reçu ce message par erreur, veuillez nous en informer par téléphone ou par message électronique et détruire les informations immédiatement. Ce message n’engage que son signataire et aucunement son employeur.

_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/


peter at rathlev

Aug 2, 2012, 3:40 AM

Post #4 of 5 (1992 views)
Permalink
Re: unblocking port on 3750 [In reply to]

On Thu, 2012-08-02 at 10:09 +0000, Bouazza Djamel wrote:
> Thank you for your swift reply. Hereunder the errors messages on switch 3750.
> Aug 2 06:06:07 CET: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 2062 on Port-channel4 VLAN1.
> Aug 2 06:06:07 CET: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking Port-channel4 on VLAN0001. Inconsistent local vlan.
> Aug 2 06:06:22 CET: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking Port-channel4 on VLAN0001. Port consistency restored.

This means that the Cisco switch, which by default assumes untagged
frames belong to VLAN 1 ("native vlan"), received a PVST BPDU belonging
to VLAN 2062 untagged. That's an inconsistency.

If this were between two Ciscos switches it could be caused by having
different native VLANs on each side. That shouldn't correct itself
automatically though.

Since the problem corrected itself I must assume that the neighboring HP
switch starts out with VLAN 2062 as untagged but switches to VLAN 1
after 15 seconds, thus restoring consistency.

> On switch 3750 :
> nterface Port-channel4
> description *** to CORE SWITCH HP ***
> switchport trunk encapsulation dot1q
> switchport trunk allowed vlan 1-999,2010,2014,2026-2055,2060-2067,2069
> switchport mode trunk
>
> On Core switch HP 12508
>
> interface Bridge-Aggregation2
> description *** to 3750 DATACENTER ***
> port link-type trunk
> port trunk permit vlan 1 to 255 257 to 999 2010 2014 2027 to 2055 2060 to 2067 2069
> link-aggregation mode dynamic

What does the physical member links look like? I'm unfamiliar with HP
swithes, but maybe the physical links have VLAN 2062 as untagged. When
they become regular members of the port-channel (LACP? Unconditional?)
they inherit the configuration from the "Bridge-Aggregation2" interface.

Maybe the configuration from the physical interfaces can shed some light
on it.

All in all I'd say that this isn't a problem as such. I just seems to
mean that the links takes 15 seconds to actually start working, but from
then it is consistent.

--
Peter


_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/


blake at pfankuch

Aug 2, 2012, 6:35 AM

Post #5 of 5 (1998 views)
Permalink
Re: unblocking port on 3750 [In reply to]

Peter/Bouazza, I haven't worked a huge amount with HP switches in the past 4 years but I would agree. There is some configuration which can be done with their link ag stuff to force it to load the config in less than 15 seconds, but its not always best practice.

Traditionally it is best practice has been to load the ag port config to the physical interfaces as well so you don't have this same issue, even though its not technically a requirement. Also means that the ports work correctly in an instance where there are not enough active ports to bring up the ag group.

-----Original Message-----
From: cisco-nsp-bounces [at] puck [mailto:cisco-nsp-bounces [at] puck] On Behalf Of Peter Rathlev
Sent: Thursday, August 02, 2012 4:41 AM
To: Bouazza Djamel
Cc: cisco-nsp [at] puck
Subject: Re: [c-nsp] unblocking port on 3750

On Thu, 2012-08-02 at 10:09 +0000, Bouazza Djamel wrote:
> Thank you for your swift reply. Hereunder the errors messages on switch 3750.
> Aug 2 06:06:07 CET: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 2062 on Port-channel4 VLAN1.
> Aug 2 06:06:07 CET: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking Port-channel4 on VLAN0001. Inconsistent local vlan.
> Aug 2 06:06:22 CET: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking Port-channel4 on VLAN0001. Port consistency restored.

This means that the Cisco switch, which by default assumes untagged frames belong to VLAN 1 ("native vlan"), received a PVST BPDU belonging to VLAN 2062 untagged. That's an inconsistency.

If this were between two Ciscos switches it could be caused by having different native VLANs on each side. That shouldn't correct itself automatically though.

Since the problem corrected itself I must assume that the neighboring HP switch starts out with VLAN 2062 as untagged but switches to VLAN 1 after 15 seconds, thus restoring consistency.

> On switch 3750 :
> nterface Port-channel4
> description *** to CORE SWITCH HP *** switchport trunk
> encapsulation dot1q switchport trunk allowed vlan
> 1-999,2010,2014,2026-2055,2060-2067,2069
> switchport mode trunk
>
> On Core switch HP 12508
>
> interface Bridge-Aggregation2
> description *** to 3750 DATACENTER *** port link-type trunk port
> trunk permit vlan 1 to 255 257 to 999 2010 2014 2027 to 2055 2060 to
> 2067 2069 link-aggregation mode dynamic

What does the physical member links look like? I'm unfamiliar with HP swithes, but maybe the physical links have VLAN 2062 as untagged. When they become regular members of the port-channel (LACP? Unconditional?) they inherit the configuration from the "Bridge-Aggregation2" interface.

Maybe the configuration from the physical interfaces can shed some light on it.

All in all I'd say that this isn't a problem as such. I just seems to mean that the links takes 15 seconds to actually start working, but from then it is consistent.

--
Peter


_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/

_______________________________________________
cisco-nsp mailing list cisco-nsp [at] puck
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/

Cisco nsp RSS feed   Index | Next | Previous | View Threaded
 
 


Interested in having your list archived? Contact Gossamer Threads
 
  Web Applications & Managed Hosting Powered by Gossamer Threads Inc.