06-19-2011 04:14 AM
On the 48 port 8Gbps line card the bandwidth that can be guaranteed is 192Gbps across the card. This means that every port can be guaranteed 4Gbps with no oversubscription. 48 x 4 =192
The confusion happens when you look at port groups. This card has 6 ports per group , each port group has 12.8 Gbps so I make that 8 x 12.8Gbps = 102.4Gbps.
Can anyone explain.
Thanks
Solved! Go to Solution.
07-03-2011 11:01 PM
Hi Steve,
you're more than welcome. Please mark the post as Answered if you're satisfied with the reply, this helps other users with the same or similar issues find the solution quicker.
Many thanks for making our little community an even better one :-)
thanks,
Kris
06-20-2011 01:50 AM
Hi,
I'm not quite sure where you got the info that the 48port 8Gb linecard has 192Gbps bandwidth across the card.
Where did you obtain that info?
Could you provide me with a show modules and a show hardware output? you can remove the serial numbers for privacy of course.
Thanks,
Kris
06-20-2011 01:56 PM
Kris,
Look at this http://www.cisco.com/en/US/prod/collateral/modules/ps5991/ps9877/at_a_glance_c45-492744.pdf
It states that the 48 port 8Gb line card has 192Gbps of full duplex bandwidth.
The show port resources shows the foolowing:
Module 1
Available dedicated buffers for global buffer #0 [port-groups 1-4] are 5016
Available dedicated buffers for global buffer #1 [port-groups 5-8] are 5016
Port-Group 1
Total bandwidth is 12.8 Gbps
Total shared bandwidth is 12.8 Gbps
Allocated dedicated bandwidth is 0.0 Gbps
--------------------------------------------------------------------
Interfaces in the Port-Group B2B Credit Bandwidth Rate Mode
Buffers (Gbps)
--------------------------------------------------------------------
fc1/1 32 8.0 shared
fc1/2 32 8.0 shared
fc1/3 32 8.0 shared
fc1/4 32 8.0 shared
fc1/5 32 8.0 shared
fc1/6 32 8.0 shared
Regards
Steve
06-21-2011 08:48 AM
Hi Steve,
thanks for your reply. I think I can clarify this for you.
You're talking about the 1/2/4/8 Gbps 48-Port FC Module, part number DS-X9248-96K9.
Look closely at the part number, it says 96K9. The 96 refers to the 96Gbps uplink to the backend this linecard has.
12Gbps * 8 portgroups = 96 Gbps. The .8 is there, so in reality you even have a little bit more bandwidth like you calculated above. It's just rounded off here for ease of viewing.
So why do our marketing documents specify 192Gbps? You'll see that this figure is closely followed by 2 very important words: Full Duplex. You have to interpret this as 96Gbps up and 96 Gbps down, good for 192Gbps total. A 4Gbps port will be able to send and receive at the full 4Gbps in each direction.
I agree that this is confusing. Unfortunately this is not going to change, simply because this is the way everyone does it in their marketing documents.
The way to use this linecard is hidden in the notion that it's 12.8Gbps bandwidth is shared, and hence you can already start connecting 8Gbps devices to your director switches by carefully designed your SAN so 8Gbps hosts share a port group with less demanding nodes.
A much higher bandwidth 8Gbps linecard and accompanying Supervisor linecard are on the horizon.
I hope this clears things up for you. You might want to also take a look at our next-gen Consolidated I/O 10Gb FCoE switches, the Nexus family. The Nexus 5596UP offers a non-blocking architecture unlike the one in the MDS 9500 and will also run plain FC ports. I'd recommend you to check with you Cisco Account team to see what exactly the differences/tradeoffs are and if this is a viable alternative for you.
07-02-2011 01:33 PM
Kris,
Many thanks for this.
Regards
Steve
07-03-2011 11:01 PM
Hi Steve,
you're more than welcome. Please mark the post as Answered if you're satisfied with the reply, this helps other users with the same or similar issues find the solution quicker.
Many thanks for making our little community an even better one :-)
thanks,
Kris
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