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Sanity check please

It's probably me but could someone have a look at this link in Cisco's campus network design doc -

http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/HA_campus_DG/hacampusdg.html#wp1108489

scroll down to figure 41 where the distribution switch interconnect is blocking and both access layer switch uplinks are forwarding. If vlan 2 is on both access-layer switches does this not form a L2 loop ?  The diagram shows both switches forwarding on vlan 2 on both links but to me that seems as though a packet such as a broadcast could origiinate on one access-layer switch and then end up back there.

If each access-layer switch had it's own vlan then i could understand the logic but not with both switches having the same vlan.

Am i missing something ?

Incidentally this is linked to the question about GLBP and STP in case anyone wants some more context.

Jon                 

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Sanity check please

You are right I see a loop. If Access A switch sends out a BPDU it will get it back through the red line in the below picture and detects a loop.

Siddhartha

Siddhartha
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