LAN Routing

2920 Stacking + 10Gbe modules (J9732A)

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Occasional Contributor

2920 Stacking + 10Gbe modules (J9732A)


I've recently inherited a network that has some underlying issues with 2x 2920 stacks, one made of 4 switches and the other of 3. Both units are running WB.16.02.0016 for the firmware.

We have 2 of these modules in each stack, both on the commander & standby switches.

From what I have been told some time ago the 10Gbe modules randomly started to loop one day, causing a complete network shutdown, at the time the only workaround seen was to remove 2x cables from the modules. 

 I will attach a picture of the network diagram of the stacks, the cables in red were removed in order to achieve network stability.
My question is this, What is the recomended configuration to achive the full 40gb connection speed available here? I'm not able to find any standard setup guide etc for these modules, only how to physically install them..
I did find this post ( im wondering if I should be setting these ports up as dynamic links?
If anyone could give me a point in the right direction it would help a lot!
Honored Contributor

Re: 2920 Stacking + 10Gbe modules (J9732A)

You made a loop (well, in made two loop within each backplane stack!); it's crystal clear.

Consider that each Backplane Stack represents a single logical entity so you shouldn't create a loop between ports of the same Stack (e.g. between 750:1/B1 and 751:2/B1 for the top stack and/or 754:1/B2 and 755:2/B1 for the bottom stack).

To create an aggregated links "uplink" between both stacks you could instead create a LACP (IEEE 802.3ad) aggregated trunk "TrkX" (let me say Trk1 on both ends) respectively made of 1/B1+1/B2+2/B1+2/B2 interfaces (Grandtotal of 40 Gbps) of top stack and another TrkY made of 1/B1+1/B2+2/B1+2/B2 interfaces (Grandtotal of 40 Gbps) of bottom stack...and interconnect them 1/B1 to 1/B1, 1/B2 to 1/B2 and so on. Simple.

The LACP configuration you linked is OK.

I'm not an HPE Employee
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Occasional Contributor

Re: 2920 Stacking + 10Gbe modules (J9732A)

Hi Parnassus,

Many thanks for your quick reply! I make the recommended changes and if all goes well mark this as resolved.