topic Re: ICX7450 switch STP Loop in ICX Switches

ICX7450 switch STP Loop

prasad_kawadkar — Mon, 26 Feb 2018 05:24:49 GMT

We have ICX 7450 switch as distribution switch and below that we have 5 nos HP 5120 as access switches in a Ring Topology. We have connected one port of 7450 to HP Access switch one and another is connected to access switch 5. If i connect both the link i found STP loop and if i disconnected one of the link, the network found stable. Earlier it was Cisco switch and now we are replacing the same with Brocade.
Please suggest.

Re: ICX7450 switch STP Loop

david_chavarria — Mon, 26 Feb 2018 17:38:44 GMT

Did you make sure to enable 802.1w rapid spanning tree on the ICX 7450 and assigning the ports going to the HPs as "admin pt2pt mac" ?

Re: ICX7450 switch STP Loop

david_ellis_h2n — Mon, 26 Feb 2018 18:14:36 GMT

If you are running routing code, spanning-tree is not enabled by default. It is enabled by default on CIsco and HP switches.

Re: ICX7450 switch STP Loop

prasad_kawadkar — Fri, 02 Mar 2018 08:24:44 GMT

Hi I have already configured the command but still has a issue...
interface ethernet 1/2/2
port-name ###UPLINK_TOWARD_10.11.64.21###
spanning-tree 802-1w admin-pt2pt-mac
dual-mode
!

Re: ICX7450 switch STP Loop

chris_hill_4zpl — Wed, 21 Mar 2018 17:49:45 GMT

I'm assuming 1/2/2 is one port leading to one of the HP switches (1). Is the other port leading to switch 5 also configured with the same spanning-tree configuration?

Re: ICX7450 switch STP Loop

david_ellis_h2n — Wed, 21 Mar 2018 21:44:48 GMT

You need to configure spanning-tree either globally or on the VLAN. I am assuming that the HP switches are default and running PVST 802.1d. You need to match that on the ICX switch. Go to the VLAN and issue the spanning-tree command and set your spanning-tree priority to some number lower than 32768 so it will be the root. This needs to be done on all the VLANs going between the switches. If you want to use RSTP, you will probally need to configure that on all the switches. I know that 802.1w is backwards compatible with 802.1d, but it is best to be all the same if possible.