ICX7450 switch STP Loop

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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.
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prasad kawadkar

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Posted 3 months ago

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Dacvar

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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"  ?
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David Ellis

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

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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
!
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chill

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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?
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David Ellis

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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.