max speed on gigabit port

Unanswered Question
Feb 13th, 2007

hi All,

is there anyone know the max throughput that i can get on WS-X6408A-GBIC ?


I have this problem too.
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Jon Marshall Tue, 02/13/2007 - 23:35


WS-X6408-GBIC is a classic line card. This means it connects to the 32Gb shared bus. So a lot depends on how many other modules you have that access the shared bus ie.

if you have a Sup1a or Sup2 then even fabric-enabled cards will be on the shared bus.

If you have a Sup2 with a Switch Fabric Module then fabric enabled cards will have dedicated connections to switch fabric. Classic cards will still use 32Gbps bus.

With a Sup720 - pretty much same as Sup2 with Switch Fabric Module except Sup720 has built in SFM.



phamthecong Wed, 02/14/2007 - 18:17

thank you Jon. our system configuration as below:

Sup 2




how do I work out the average speed for each port? or any doco would be appreciated.

Jon Marshall Wed, 02/14/2007 - 23:48


It can be a bit of minefield with the 6500 line cards :-)

If you have a Sup 2 but no Switch Fabric Module (which takes up a separate slot) then all your cards are running on the shared 32Gbps. So as it is shared between these modules it is difficult to give an average speed per port.

In additon a blade like the WS-X6548-GE-TX has a 1Mb buffer size per port but then groups 8 ports together so you end up with 1Mb for 8 ports. This again will have an effect.

It is a easier to do average speeds when you have fabric enabled linecards with either a Sup2 + SFM or a SUP720 as they have dedicated connection to switch fabric.

Note your 6516 & 6548 are fabric enabled but as you don't have an SFM they must use the 32Gbps bus.

Here's a link that covers the capabilties of all the 6500 modules.




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