Alcatel Unleashed

I have a pair of OS6900-V48C8 running OS 8.8.56.R02, in virtual chassis. Port groups 1/1/7 and 2/1/7 were set to auto speed, and 10G transceivers were plugged into ports 1/1/30 and 2/1/30, so the groups autoconfigured themselves to 10G speed. The remaining ports in these groups (25, 26, 27) were empty. I have removed these two transceivers and plugged in 25G active optical cables into all four ports in each group (1/1/25, 1/1/26, 1/1/27, 1/1/30, 2/1/25, 2/1/26, 2/1/27, 2/1/30), but the groups as a whole stayed at 10G and refused to go into 25G mode, with the ports staying in 'down' state. I tried running 'interfaces portgroup port-group-num 1/1/7 speed 25g' to force the group to change mode, but this had no effect. In the meanwhile, I just plugged the servers into another group which hadn't had 10G transceivers installed in it, but going forward, is there a way to reset this group without power cycling the switches?

The SFP module dictates the speed in most cases. It's very rare that an SFP supports dual speeds, so settings like this are not required/have no effect.

I have never heard of this "reset portgroup speed" on a 6900, I expect the problem to simply stay after a reboot. Do you use certified Alcatel SFP/DAC cables?

No, we use fs.com AOCs in this case, but they work without any issues in other port groups that hadn't had 10Gb modules plugged into them before.

I would suggest grabbing the latest firmware then.