10 GB Question

Unanswered Question
Jul 15th, 2009

I'm looking at the datasheet for the WS-X6708-10G-3C at this link:


It says that the Supervisor 720 is supported, but doesn't give any specifics. I have a Supervisor 720 with a PFC-3A. Am I correct in thinking that you cannot run the X6708-10G-3C without a PFC-3C?

Second question - in order to get to the PFC-3C, am I correct in thinking that there is not an upgrade path? Basically, we need to replace the Supervisor 720 (PFC3A) with a VS-S720-10G-3C?

Thank you,


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Giuseppe Larosa Wed, 07/15/2009 - 23:36

Hello Joe,

we have 6708 with DFC3CXL on systems with sup720 3BXL a warning message appears telling that the module has a better DFC then the system but we can use it.

About upgrade path the safe choice is to purchase an new sup720 3C or 3CXL

otherwise you need to update to 1GB with 1GB chips both RP and SP and to buy the PFC3C and to change the current PFC.

Hope to help


Joseph W. Doherty Thu, 07/16/2009 - 02:58

"otherwise you need to update to 1GB with 1GB chips both RP and SP and to buy the PFC3C and to change the current PFC."

Are you sure?

Reason I ask, when -3C was announced (if I recall correctly, 1st announced as ws-sup720-3c[xl], [shortly] later "renamed" vs-s720-3c[xl]), and VSS described, was very much interested in upgrade from sup720-3bs to -3cs. Info was, wasn't possible. (NB: got this info 2nd hand, but my understanding answer provided by Cisco.) (One issue, especially to guarantee support of VSS is dual 10G ports on -3cs.)

Anyone else's two-bits?

Giuseppe Larosa Thu, 07/16/2009 - 04:32

Hello Joseph,

you are right I've described in that sentence a possible upgrade from 3B to 3BXL.

However, even if it would be technically possible you get a system with a not well recognized hardware confiugration so it could a problem to open TAC service requests so it is better to replace.

the VSS capable supervisors are different they have an additional ASIC for managing the VSL link with proprietary encapsulation as explained some time ago by a Cisco engineer in lan forum.

Hope to help



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