Cisco 520 Express switches vs Procurve Spanning tree

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Sep 2nd, 2009
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we have several cisco ce520-24pc-k9 access switches that all have two uplink connections to two HP Procurve 54012zl edge switch (one uplink to every HP switch).

But the ce520 is standard using PVST+ as a spanning tree protocol, but the HP use Multiple Spanning Tree (MST).

What now happens that one of the two Gi ports falls in error ( unknown ST BPDU's).

The manual of the cisco ce520 says that the following Spanning Tree protocol are supported

• Per VLAN Spanning Tree

• Per VLAN Spanning Tree Plus

• Per VLAN Rapid Spanning Tree Plus

Is there a solution so my spanning tree will work between the cisco and HP device?


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Giuseppe Larosa Thu, 09/03/2009 - 12:57
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Hello Marcel,

I would suggest to try with Rapid PVST+ because it uses 802.1W for each instance as MST does.

Hope to help


m.slotboom Tue, 10/06/2009 - 04:04
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That is the problem de ce520 uses Rapid PVST+ this is a cisco protocol so far I know.

Rapid PVST+ cannot communicatie with an MST instance. The CE520 sets one of the two uplink ports in an error state.

In the documentation of the ce520 they write that the ce520 can support more spanningtree protocols (RSTP and STP) But I can't config this in the webinterface of the ce520 switch, the option is grayed out.

I can accept that one of the two ports are in blocking state by RSTP ot STP, but now one of the two ports is in error state.


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