hsrp error and network crashed

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Jul 30th, 2009
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we had a network outage and logs isnt giving enough information. there was a change on etherchannel though prior to the outage. the logs doesnt given enough evidence

6500 A ---port channel 1---- 6500 B


6500 A is also connected to HPSW1 with portchannel 2

6500 B is also connected to HPSW2 with portchannel 3


HPSW1 and HPSW2 arent connected to each other


port channel 1 allows all vlan. the native vlan on port channel 2 and 3 is 113

what happened is

on 6500 A, 2 ports were addded to portchannel 2. these 2 ports were in shut mode.

similarly on 6500 B, 2 ports were added to portchannel 3. these 2 ports were in shut mode and they are not physically connected at the other end

once these 2 ports on both 6500 A and 6500 B were made up with no shut, we started getting the below error and network crahsed for few mins before it came up

%STANDBY-6-STATECHANGE:

HSRP failover happened for all the vlans

we suspect there was a stp loop prevention calculation which caused this. but the logs deosnt give enough evidence

will a port when added to a portchannel cause stp calculation.

in this scenario all vlans are allowed between both 6500. on HP switches stp is disabled.

we didnt see any other logs for this issue

thanks



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Giuseppe Larosa Thu, 07/30/2009 - 12:07
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Hello Munaa,

the message %STANDBY-6-STATECHANGE: is usually seen during bridging loops and broadcast storms because bidirectional communication is not working well and it is intermittent.


you say you have added two links on each channel-group that the links were in shut and not connected

You then unshutted the new links and problem started.


were the new links configured as trunks with same encapsulation and same list of allowed vlans before unshutting ?


Are you using channel-mode on = no negotiation of bundle?


Hope to help

Giuseppe


Peter Paluch Thu, 07/30/2009 - 12:17
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Hello,


Just two questions: why is the STP disabled on the HP switches? Have you tried turning it on?


Best regards,

Peter


followurself Thu, 07/30/2009 - 12:30
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STP has always been disabled on HP switches. we didnt tried turning it ON

only change was add 2 ports on existing etherchannels. these ports were shut and then we did a no shut

since these ports were part of portchannel, they became part of the trunk port.this trunk port doesnt allow all vlans but it allows vlan 113, which is a native vlan for tht trunk

port channel between 6500's allow all vlans

channel mode is set to on

followurself Thu, 07/30/2009 - 12:32
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were the new links configured as trunks with same encapsulation and same list of allowed vlans before unshutting ?

Yes


Are you using channel-mode on = no negotiation of bundle?

channel mode on


followurself Thu, 07/30/2009 - 12:48
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6509A----HP1

6509B---HP2

6509 A and 6509 B both interconnected

HP1 and HP2 are not interconnected. but the trunk between HP1 to 6509A and HP2 to 6509 B allow same vlans

STP is hence disabled on HP1 and HP2

Giuseppe Larosa Thu, 07/30/2009 - 12:55
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Hello Munaa,


if the links were properly configured and unconnected I don't see why enabling them should cause a problem, are you sure that no unwanted cross-connect

6509A --- HP2 and 6509B -- HP1 was not made with the new links?


About STP:


let's suppose someone connects a cross-over cable to two ports of an HP switch what will happen with STP disabled?


I would use LACP if possible on the bundles


Hope to help

Giuseppe


Peter Paluch Thu, 07/30/2009 - 13:00
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Giuseppe,


I agree completely. The HPs should definitely run STP and if possible, the EtherChannel should be managed by LACP. I believe that HP ProCurve switches support it so there should not be a problem in setting it up.


Best regards,

Peter


followurself Wed, 08/05/2009 - 06:12
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thankx

what are advantages of using LACP instead of portchannel

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