Contention on 5412R using a 8 x 10Gb SFP+ module (J9538A)

[Network_Support]

We have recently been informed that if we use a 8 x 10Gb module in our 5400R series chassis (the new one) that we would expect to see contention of 2:1 between the ports and anything else i.e. we can only run 4 of the ports at 10Gb/s full speed.

We are a bit surprised as the 5412R is specified as having a 2Tb/s switching fabric.

Is anyone able to confirm or deny this?

Thanks

[n3tm1n]

My company just purchased a 5406R with 4 10G B-T  modules. If you statement is correct, I am going to be one pissed customer and returning the unit.

[Vince-Whirlwind]

2:1 oversubscription on the 5412R is also my understanding.

I've rarely seen 10Gb uplinks with any significant utlisation on them, so this isn't a problem for me, but if you are using server blade chassis that are capable of pumping out high levels of traffic out one interface, you might want to either space your 10Gb ports on the 5412R or think about your traffic flows and use some top of rack switches like HP5900s.

[Network_Support]

When you say it's your understanding, is this from a HP source or reseller because we cannot see anywhere in the product documenation which says this is the case?

Thanks

[n3tm1n]

To the OP,  your statement is correct. I inquired about this with HP support and here is the document detailing this.

The 8 port module (v2) has only 2 channels each supporting up to 23.6 or so Gbs (total 46Gb per module).

They provided me with the link to the document refering to this (page 69)

http://www8.hp.com/h20195/v2/GetDocument.aspx?docname=4AA0-5388ENW

Note it's specific to the module and not the chassis switch itself. However, I will be contacting HP for a return for false marketing. I have basically 12 ports that are useless for my purposes.

They have the audacity to market that the switch can scale up to 96 10Gb ports (12 mod system) which is utter garbage.  Be honest and say 10 Gig utilization per module is half that.

[Vince-Whirlwind]

I don't understand why you think you can return your switch.
Oversubscription on switch modules has been around for years. It is completely usual.
If you need line-rate cards then that's what you ask for. Even better would be to use a professional consultant with networking expertise to explore these issues before drawing up a BOM.

[MichaelM55]

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@Vince-Whirlwind wrote:
I don't understand why you think you can return your switch.
Oversubscription on switch modules has been around for years. It is completely usual.

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And therefore it should also be noted within the datasheet of 5400R switching series.

[Vince-Whirlwind]

The Cisco 4507 has exactly the same bandwidth - on a fullsiIzed module