[Buildbot] #3183: fix network "spottiness" on new infra

[Buildbot trac]

#3183: fix network "spottiness" on new infra
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Reporter:  dustin    |       Owner:  verm
    Type:  defect    |      Status:  accepted
Priority:  critical  |   Milestone:  sys - other
 Version:            |  Resolution:
Keywords:            |
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Comment (by verm):

 I dumped the switch config and carefully compared it to my cable plan.  I
 also checked the mac address tables for each port group.  I don't see
 anything obviously wrong.  I'll get the OSL to verify the cabling anyways
 just to be thorough.

 After this I will look for bugs in the OS version on each switch and
 possibly upgrade.

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Ticket URL: <http://trac.buildbot.net/ticket/3183#comment:35>
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