Connecting new XS708? switch to existing GS7xx switch stack

Hi CCTalbert

Welcome to the Community!

Your GS728TPS/GS752TS Smart Switch stack uses AGC761 stacking cables, in fact 2.5G SFP DAC cables. This older generation of Smart Switches advertizes 10G stacking due to the Ring stack topology: each AGC761 provide 2.5Gbps half-duplex, so 5Gbps full duplex when inserted into one SFP port. When there are two AGC761 per switch (one connection up, one connection down in the stack, with the last switch going back to first switch in the stack per the ring topology) then you get 2 x 2.5Gbps half-duplex interconnect, so 10Gbps full duplex stacking speed.

On these GS7xxTS/TPS models, the SFP ports can do typical 1Gbps with SFP GBICs; or 2.5G with AGC761 2.5G DAC cables.

Yes, your new 10G Smart Managed Switch like XS708T or new 10G Web Managed (Plus) Switch like XS708Ev2 will only come with 10G SFP+ ports. These SFP+ ports supports 10G speed and 1G speed; but not 2.5G. So using fiber SFP+ port, you can use 1G SFP GBIC to connect your current switches.

You are right, it might be better to use Link Aggregation (port channel) with several copper ports instead. I would advise a distributed LAG across your GS7xxTS/GSxxTPS stack, with for instance one port per switch, or more per your bandwidth / oversubscription requirements. The same LAG would be created on your new 10G Switch.

Maybe this will be useful: if you want to use LACP (dynamic LAG) for this interconnect, or with your servers, you may want to go with 10G Smart Managed Switch like XS708T. Because Web Managed (Plus) Switches will only provide static LAGs (no LACP).

I hope this helps, let us know how it goes!

Regards,