From: lalit gupta (lalit.tech@gmail.com)
Date: Wed Feb 06 2008 - 16:30:42 ARST
CEF720 linecards, these have either 1 or 2 fabric connections to the switch
fabric. The 6724 linecard is the only one that has a single fabric
connection, all the rest of 6700 series have 2 fabric connections. They also
come by default with this CFC, or centralized forwarding card, and this is
what connects them to the bus. the CEF720 cards never forward data over the
bus, they only forward data over the switch fabric. The only thing they use
the bus for is control information, so headers to and from the Supervisor to
do lookups, basically.
a CFC provides central connection to the Catalyst bus for a CEF720 linecard.
So if you don't order a CEF720 linecard with a DFC, it gets a CFC by default
so that it can do local centralized forwarding and send the packet headers
and what not up to the Supervisor over the bus. If you order a Sup720 with a
DFC, then just replace this with a D, you no longer have a bus
connection because
you're doing your lookups locally and there you go. So the CFC is just to
provide centralized forwarding capability if you don't have a DFC.
Hope it will help in understanding more of architecture side
Thanks and Regards
Lalit
On Feb 6, 2008 12:13 PM, Steeneken, Robert <Robert.Steeneken@getronics.com>
wrote:
> If you only use 67xx cards and no classic cards I dont't think you need
> DFC's on the line cards.
> The 67xx cards have a 40Gbps fabric to the sup720. With the DFC's line
> cards keep local traffic on the card, and can directly send traffic to
> another linecard without sending it first to the sup.
> So you create more bandwidth with the DFC's , the PFC on the sup is only
> used for the uplinks on the sup itself.
>
>
>
> ________________________________
>
> Van: nobody@groupstudy.com namens Rookie Ccie
> Verzonden: di 5-2-2008 16:53
> Aan: ccielab@groupstudy.com
> Onderwerp: 6500 - 67xx line cards
>
>
>
> Dear Group,
>
> Please let me know whether we need to use DFC-3C cards on 67xx line cards
> to
> get 40Gbps per slot capacity. I went through lot of Cisco doc's but could
> not find that it is required (DFC-3C).
>
>
> Regards
>
> Uchil
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Sat Mar 01 2008 - 16:54:47 ARST