Unanswered Question
Nov 22nd, 2007
User Badges:

It says that this card has a single 20 Gbps connection to the switch fabric.

Does this mean 20 Gbps full duplex?

Since there are 24 ports, are we getting 2.4:1 oversubscription with this card?

If this is the case is there any other gigabit sfp based card that supports sup 720 with a closer to wire-rate performance?

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
Jon Marshall Thu, 11/22/2007 - 07:29
User Badges:
  • Super Blue, 32500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN


It means that you have 24 ports capable of running at 1Gbps each. You have a 20Gbps connection to the backplane, yes it is full duplex that is how Cisco come to the figure of 720 as in Sup720 eg

6509 =

9 x 40 = 360 ( possible 40Gbps connection to switch fabric per module )

Full duplex = 2 x 360 = 720

So it's not really a 2.4:1 oversubcription it's actually quite close to 1:1. If you left 4 ports free you would have no oversubscription at all.

You could look at the 6748-SFP module but that as 2 x 20Gbps connections at full duplex so it's the same contention rate.




This Discussion