ws-x6704-10ge query

[Subin Kallidumpil]

Hi Team,

I would like to know if we can use the following card i.e. WS-X6704-10GE along with SUP-2T which will be configured in VSS.

This line is supported with SUP-2T, however not sure if the sup 2t will be configured in VSS. If any supporting document can be provided for the same , that would be great.

If this is supported than whether i would be getting line rate/non blocking capacity with WS-X6704-10GE. Since SUP-2T provides 80 Gbps bandwidth per slot.

Regards

K Subin

[Giuseppe Larosa · Accepted solution]

Hello Subin,

if equipped with a DFC4 or a CFC the WS-6704 should be supported also in the VSS

see

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/15.1SY/release_notes.html#wp4765684

and

>> Switching modules with a CFC, DFC4, or DFC4XL support VSS mode.  

sup2T config guide

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/15.1SY/config_guide/sup2T/virtual_switching_systems.html#wp1053927

However, the WS-6704 cannot be used to build the VSL link as it misses the ASIC that support the VS protocol.

The VSL HW requirements are:

VSL Hardware Requirements

The VSL EtherChannel supports only 40-Gigabit and 10-Gigabit Ethernet  ports. The ports can be located on the supervisor engine (recommended)  or on one of the following switching modules:

•WS-X6904-40G-2T

•WS-X6908-10GE

•WS-X6816-10T-2T, WS-X6716-10T

•WS-X6816-10G-2T, WS-X6716-10GE 

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/15.1SY/config_guide/sup2T/virtual_switching_systems.html#wp1053927

Hope to help

Giuseppe

[Subin Kallidumpil]

Guiseppe,

Thanks a lot for the reply. Could you please provide the answer for the last part also i.e. whether i would be getting line rate/non blocking capacity with  WS-X6704-10GE. Since SUP-2T provides 80 Gbps bandwidth per slot.

[Giuseppe Larosa · Accepted solution]

Hello Subin,

the WS-6704 has two connections to the fabric at 20 Gbps / per direction

>>Dual switch-fabric connections:

Fabric Channel #1: Ports 3 and 4

Fabric Channel #2: Ports 1 and 2

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/15.1SY/release_notes.html#wp4765684

The Sup2T runs the connections in backward compatibility mode as it detects a WS-67xx mode.

>> Each channel can operate at either 40 Gbps to  support the new WS-X69xx linecards, or 20 Gbps to provide backward  compatibility for WS-X67xx and WS-X68xx linecards

from sup2T Architecture white paper

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/white_paper_c11-676346.html#wp9001559

So the WS-6704 will get 2 X20 Gbps per direction dual connection to the Sup2T crossbar switching fabric.

But this is enough to run non blocking, and actually the module runs non blocking also on a sup720 chassis.

Hope to help

Giuseppe

[Subin Kallidumpil]

Thanks a Lot guiseppe.....

[Joseph W. Doherty]

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Posting

BTW, if full bandwidth from fabric to 10g port is your objective, you have a coupld other options.  First, the other 10g cards often offer a "performance" mode, where they deactivate ports so you will obtain full fabric bandwidth to 10g ports.  Second, if you carefully review documentation on oversubscribed 10g line cards, you'll find what ports share fabric bandwidth.  If you only use specific ports, you can reduce or eliminate oversubscription to specific ports.

BTW, I recall when the 6702 and 6704 were both available, the former was documented as truly non-oversubscribed, the latter was not.  If I remember correctly, the fabric actually provided just a smidgen less bandwidth then 20g per channel.

Also keep in mind, as it's not uncommon to have multiple ingress ports sending to the same egress port.  I.e. the port itself can congest.  Assuming this is transient, the latter higher density 10g cards provide more port buffering memory.  In other words, something like a 6708 might perform better than a 6704 especially if running in performance mode.