Security

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  • 1.  Link Aggregation or Spanning Tree?

    Posted 09-17-2012 10:50

    Hello,
    I have two EX4200 fiber blades setup in a virtual chassis acting as my network core. Currently I am using Link Aggregation with LACP over two fiber ports to several HP Procurve switches throughout the building as a make shift redundancy. The second fiber blade is new and I now plan to move the second fiber port to the new blade. If one fails the other just takes over and everything is great.

     

    I also will be plugging in a Cisco 5508 wireless lan controller which may some issues with that. The Cisco docs and forum clearly warn against spreading the lag across multiple blades, not clear about a virtual chassis though. Not a big deal as we have two controllers, so one per blade.

    My question then, should I use link aggregation with lacp for the redundancy or should I just use spanning-tree? I want the lowest outage time possible so using a more talkative protocol is not a concern at this time. Thoughts?

     

    Thanks,

    Todd



  • 2.  RE: Link Aggregation or Spanning Tree?

    Posted 09-17-2012 11:20

    Hi Twinkie,

     

    you can look at the vc as one chasis, so LAG shouldn't be a problem and is much faster then SPT. An alternative for spt could also be a redundant trunk group. One active, one passive link from different members. If the active link goes down, the backup comes up, subsecond.

     

    Good luck!



  • 3.  RE: Link Aggregation or Spanning Tree?

    Posted 09-17-2012 15:17

    I can't find anything about connecting a redundant trunk group up to a procurve device and I don't have any time to test new ideas at the moment.  I will keep that in mind though.  The other benefit to LAG was the additional bandwidth as I recall but I think that the HP Procurve did not fully support that so it may not be an issue.  I plan to test the LAG response time to losing a port and spreading them accross the virtual chassis tonight.  I will let you know.

    -Todd