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CFC & DFC3C Line cards mixed into a VSS system

Answered Question
Jul 31st, 2012
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Hi,


I understand that both CFC and DFC3C cards are comptable with line cards in a VSS system. However, I would like to know whether it is possible to have a mix of these CFC & DFC3C line cards within a VSS system. e,g 2 CFC line cards and 2 DFC3C cards. If it is possible what are the potential shortcomings? Will the line cards perform at the lowest common denominator in the VSS system- so at CFC?


Please help!!


Thanks,

Correct Answer by Edison Ortiz about 5 years 2 weeks ago

The CFC has no local DFC (no local switching is performed and the module will use the PFC for switching) so the lowest common denominator does not apply here.

If you were to have a DFC3B, then you won't get VSS Support as it demands DFC3C on modules supporting local switching.


Regards,


Edison

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Correct Answer
Edison Ortiz Tue, 07/31/2012 - 06:56
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The CFC has no local DFC (no local switching is performed and the module will use the PFC for switching) so the lowest common denominator does not apply here.

If you were to have a DFC3B, then you won't get VSS Support as it demands DFC3C on modules supporting local switching.


Regards,


Edison

Gurjinder Judge Tue, 07/31/2012 - 07:00
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Thanks Edison for your reply


Does this mean that both DFC3C and CFC line cards can be used within a common VSS system without effecting each other?


Is there any documentation that supports this?


Regards,

Gurjinder

Gurjinder Judge Tue, 07/31/2012 - 07:45
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That I understand, but can both be used in 1 chassis that forms part of a VSS and if so, is there any supporting documentation?


Thanks,

Gurjinder

Edison Ortiz Tue, 07/31/2012 - 08:36
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Didn't the link I provided explained that?

Here is another link:

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/vss.html#wp1053927

PFC, DFC, and CFC Requirements


The VSS supports any 67xx series switching module with CFC hardware.


The VSS supports DFC3C or DFC3CXL hardware and does not support DFC3A/3B/3BXL hardware.


If any switching module in the VSS is provisioned with DFC3C, the whole  VSS must operate in PFC3C mode. If a 67xx series switching module with a  DFC3A/3B/3BXL is inserted in the chassis of a VSS, the module will  remain unpowered, because VSS supports only DFC3C and DFC3CXL.


If the supervisor engines are provisioned with PFC3C, the VSS will  automatically operate in 3C mode, even if some of the modules are 3CXL.  However, if the supervisor engines are provisioned with PFC3CXL, but  some of the modules are 3C, you need to configure the VSS to operate in  3C mode. The platform hardware vsl pfc mode pfc3c configuration command sets the system to operate in 3C mode after the next restart. See the "SSO Dependencies" section for further details about this command.


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Gurjinder Judge Tue, 07/31/2012 - 08:43
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I've already seen this. I want to know if BOTH can be used in the same chasis as part of VSS:


So in one of the 6500 chassis in the VSS can I use:


1 line card with CFC

1 line card with DFC3C


without any issues...?

Edison Ortiz Tue, 07/31/2012 - 08:48
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I said YES multiple times so does the documentation!

Edison Ortiz Wed, 08/01/2012 - 06:54
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Glad to be of help.


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