Forwarding cards

[amansoi_5]

Sir,

What exactly is difference between DFC & CFC cards ? on 6500 series modules , with which module these daughter cards are used ...?

What is difference between DFC3A, DFC3B & DFC3BXL ?

Can i get any Cisco site where documentation is available ?

regds,

aman

[Roberto Salazar]

DFC are on borad the line card itself and since the DFC does look ups, the forwarding decision. CFC is *Centralized* forwarding which as the name implies the forwarding decision is doen cetralized on the sup's PFC and not doen locally on the line card.

The diffence on between DFCs are the forwarding capability.

This highlight the main diffrences:

http://www.cisco.com/en/US/products/hw/switches/ps708/prod_bulletin0900aecd8017a5db.html

[amansoi_5]

Sir,

thanks for the same ....

Can i get any site where I can find information on CFC also ?

regds,

aman

[Roberto Salazar · Accepted solution]

Not really because the CFC does not do local forwarding, so the forwarding is done by the PFC in the sup. since the forwarding is centralized this means the PFC's perfomance, fib entries, acl labels, etc. are shared among the line cards that uses the sup's PFC for forwarding, unlike a line card with local DFC which can do all the PFC does but on the line card itself.

[cassmith]

Hello, I have a similar line of questions: Is the following true:

The CFC modules reside on the 6700 series cards and come with them by default?

Thier only purpose is to connect to one of the CEF720 fabric connections? So that the central forwarding can occur?

They are replaced by DFC3's when distributed forwarding is desired?

Appreciate any responses!!

[Roberto Salazar]

The CFC modules reside on the 6700 series cards and come with them by default?

>> Yes. Otherwise it will come with DFC in different flavors - 3A, 3B, and 3BXL.

Thier only purpose is to connect to one of the CEF720 fabric connections? So that the central forwarding can occur?

>> All 67xx line cards do not have bus connection and therefore they can only work with the fabric connection. IF they have CFC that means the forwarding decision is done on the sup's PFC versus if there is a local DFC on the line card then all the forwarding decision can be made locally on the line card.

They are replaced by DFC3's when distributed forwarding is desired?

>> When DFC is present, yes the forwarding is done locally on that line card.

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