Setting up Spanning Tree on a Network

[Eric Hutchinson_2]

We have a network with three HP 5900 AF cores connected with dual redundant 10 gig fiber links running as Bridge Aggregation interfaces. Underneath these core switches are a number of Aruba/Procurve switches. Spanning tree was never setup. We need to start implementing this. Is there a good set of Documentation I can use to start planning for implementation. There is quite alot of documents I can get from the HPE site but I dont know where to start. Can anyone point to "one" document I can start with?

Thanks

[cgu]

you may want to consider using TRILL instead of spanning tree since it's way more modern and the 5900 support it. You should find a "trill configuration guide" document in the in the documents repo.

[HP-Browniee]

Hello

I can't give a you a specific document, but the first thing you should know is that when you will enable stp, it will cause network interuption.

mstp is the default now, and i suggest you keep this.

The first thing you have do to is to assign a root switch in your spanning tree topologie. you can choose this by configuring the lowest stp priority on that switch. (Your core switches should be the root)

After that you can enable spanning-tree on all your other access switches, just make sure that the stp priority on your access switches should always be higher then on the core switches.

After you enable stp on any device it will calculate the best path to the root switch, this proces will disable the ports for a brief time (few seconds).

[Eric Hutchinson_2]

Thanks Brownie and cgu for your input. I think my main obstacle in this process is the fact the network is already built and I dont want to knock people off the network while I configure it. If that is the case then so be it. What we are trying to fix is we have Mitel IP phones. On the back of these phones are two connection points. One for the network and one for the pc.  When you set this up properly the phone goes into the network jack. The switchport this is connected to has a tagged voice vlan config for the phone operation. The untagged vlan is for the PC which is connected to the other jack in the phone acting as a passthrough for the PC's data connection. We have had issues where we think loopbacks are somehow happening from swapped cables or someone plugging in another live connection into PC port on the back of the phone. Basically someone is causing broadcast storms (I think) and I need to stop it. It happens very infrequently so I do have time. Unfortunately it is pretty destructive when it happens taking out most if not all of my phones. Seeing what I am up against can anyone comment on what would be more disruptive to my network as far as implementation? Trill or STP? In the meantime I will be reading up on Trill.

Thanks again

[HP-Browniee]

In that case you better configure loopback-detection on all access ports, when a loop will occur it wil disable the port that causes the loop.

[Eric Hutchinson_2]

Thanks Brownie,

Does enabling loopback-protection on a core involve the same downtime problems as STP. Will it also work on a Procurve ASIC switch?

[HP-Browniee]

You should only enable it on your procurve switches. You don't want  it configured on your core switches. 

If you configure it on core level it will disable your uplink port to a certain access switch when a loop occurs. And in my opinion, you don't want that.

If you only configure it on your access switch, it will only shut the source port of the loop.

Configuring loopback-detection will not cause downtime.

[Eric Hutchinson_2]

Thanks Brownie,

If the second port they plug into is to another Procurve without loop back I take it broadcast storms would happen. This scenario is unlikely but possible. If that is the case and I have loop back protection enabled on that switch as well would that loop be detected and stopped.

[HP-Browniee]

I think that it will not stop the loop even if you configure it on both switches. I have to test it.

Loopback detection only works  locally on the switch. So for example if you plug somthing in port 1 and 2 of the same switch.