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stack group trunk issue ,5406, 2824

Frequent Advisor

stack group trunk issue ,5406, 2824

the core switch is 5406 with 24 MiniGBIC module and 24 10/100/1000M module.
stack group 1 to group 8 are composed by 2824 or 2626 PWR.

5406 use 2 fiber to each stack group.
"trunk a1,a2 trk1 lacp
trunk a3,a4 trk2 lacp
and in stack group.
fist uplink port and the last switch uplink port:
"interface 24
lacp enable"

Q1: does this trunk type between stack group is suitable ?

Q2: From group 1 to 6, itâ s ok.both fiber led is light. But group 7 and 8 , the trunk fiber led only one light. Why ?

i have check the ProCurve_Switch_5400zl_Series_Reviewers_Guide ,does this issue cause by "28.8 Gbps backplane interface per Line Interface Module " ?

Thank you in advance. please check the attached layout .

ray ma
Matt Hobbs
Honored Contributor

Re: stack group trunk issue ,5406, 2824

Ray Ma,

What you are trying to do is not a supported trunk configuration. Trunks need to go point-to-point between 2 switches only.

In your setup you are setting the trunk on the 5400 and you are then connecting each port of the trunk to different switches. This is not supported.

You should enable spanning-tree only, or if you want to use trunks, you will need to use 2 trunks per stack.

For example:
5400 - trk1(a1,a2) connect to 2800-1
trk2(a3,a4) connect to 2800-4

2800-1 - trk1(47-48)
2800-4 - trk1(47-48)

Spanning-tree would also need to be enabled and would block the link between 2800-2 and 2800-3.
Mohieddin Kharnoub
Honored Contributor

Re: stack group trunk issue ,5406, 2824


In a simple words, don;t consider your setup with trunks, just say you have a redundant links between the core and each Stacked (cascaded) switches.

You just need to run Spanning Tree to make sure you have a loop free topology, but in this case you will cause one of the links to be blocked by spanning-tree, so you can consider MSTP version in this case if you have Vlans.

If your fiber cable has more than 8 cores so you can get 4 links between the Core and each Stacked groups, in this case, you can implement Matt's suggestion to have 2 Trunks, first one from Core to first switch in the stack and the second one from core to the last Switch in the stack.

Good Luck !!!

Science for Everyone
Frequent Advisor

Re: stack group trunk issue ,5406, 2824

thanks for all your reply.
i have done the span config. i have solved this problem today.

Frequent Advisor

Re: stack group trunk issue ,5406, 2824

thanks very much