Powerconnect 8100 Spannig Tree with Cisco 3750

Spanning tree is enabled on the PowerConnect switch by default. When plugged into the network it will go through the elective process on it’s own, and amongst the switches they will determine the root switch and what status to place ports in. In a small network this may work out well and nothing else is needed. But in other cases it may be more desirable to specify root through manually setting priority.

If you can give us a rundown of your topology and what you want to achieve, we may be able to offer some advice.

Here are some good white pages to read through also.

www.dell.com/.../app_note_13.pdf

www.dell.com/.../app_note_1.pdf

Thanks

I have a stack of 2 x Powerconnect 8164 as core switch/router

And several Cisco Catalyst 3750 as access switches connected directly to the core through LACP channels.

I would like enable Spanning Tree for security (I have no loops) with the Powerconnect as root.

Powerconnect has RSTP as default method and Cisco has PVST.

If I enable both: Powerconnect appears as root and Cisco appears as root in each VLAN

On the Cisco switch enabling RSTP should be pretty basic. I believe all you need to do is globally run this command on the switch.

#spanning-tree mode rstp

Here are some links that go into further detail .

www.cisco.com/.../technologies_white_paper09186a0080094cfa.shtml

www.cisco.com/.../swmstp.html

OK, thanks

They don't have the RSTP option, but  when you enable MST by using the "spanning-tree mode mst" global configuration command, RSTP is enabled and they are working.

Now I have a problem with a Force10 S55 access switch connected with a portchannel trunk to the PWC 8164. When I've enabled RSTP in the 8164, the two ports of the F10 channel have passed to blocked state.

I've enabled rstp in the F10 and rebooted the switch but they continues as Blokedports

Any help?

Thanks

I would double check the S55 settings and make sure the ports are set in a matching portchannel..

We can also try plugging only one port in of the portchannel and see if that one ports goes into a blocking status.

Does the S55 plug into any other networking devices?

The S55 only plugs into the PWC8164 and the ports are in the same channel.

I switch off the S55 and the ports remain in blocked state (show span tree blockedports) , is it normal? How can I reset those  blocked ports?

What happens if you physically unplug one port, and then both ports? Are there any other ports in this channel?

To force the ports to forwarding you can disable spanning tree on the channel, or enable portfast. But if the port is entering blocking state it us probably doing so for a reason.