3560x ASICs

[aeryilmaz]

Hi all,

I've read through some of the discussions here regarding the 3560x ASICs, but still not clear on the architecture.

I see 3 port-asics on the 3560x. What is the job of these ASICs?

Also, what is the total throughput of the 3560x series?

I'm researching interface output drops that correlate with drops that I see on the corresponding asic.

I also have a lot of buffer misses in the public and interface buffer pools.

#sh platform port-asic stats drop asic 1

Port-asic Port Drop Statistics - Summary

========================================

  RxQueue Drop Statistics Slice0

   RxQueue 0 Drop Stats Slice0: 0

   RxQueue 1 Drop Stats Slice0: 0

   RxQueue 2 Drop Stats Slice0: 0

   RxQueue 3 Drop Stats Slice0: 0

  RxQueue Drop Statistics Slice1

   RxQueue 0 Drop Stats Slice1: 0

   RxQueue 1 Drop Stats Slice1: 0

   RxQueue 2 Drop Stats Slice1: 0

   RxQueue 3 Drop Stats Slice1: 0

  Port  0 TxQueue Drop Stats: 3712363

  Port  1 TxQueue Drop Stats: 0

  Port  2 TxQueue Drop Stats: 97030

  Port  3 TxQueue Drop Stats: 1450621

  Port  4 TxQueue Drop Stats: 3834

  Port  5 TxQueue Drop Stats: 210196

  Port  6 TxQueue Drop Stats: 0

  Port  7 TxQueue Drop Stats: 0

  Port  8 TxQueue Drop Stats: 1

  Port  9 TxQueue Drop Stats: 0

  Port 10 TxQueue Drop Stats: 5294

  Port 11 TxQueue Drop Stats: 875

  Port 12 TxQueue Drop Stats: 0

  Port 13 TxQueue Drop Stats: 4191

  Port 14 TxQueue Drop Stats: 0

  Port 15 TxQueue Drop Stats: 1025

Thanks in advance!

[Joseph W. Doherty]

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Posting

Regarding 3560-X performance, I believe all are line-rate/wire-speed capable.

Do note though, that does not preclude drops on congested interfaces which is probably your issue.

[aeryilmaz]

Is interface congestion due to limitations by the ASIC or caused by what's connected on the other end? Given the 3560x is wire-speed, is it still possible to over subscribe the ASICs? Based on some reading outside of this forum, I understand that there are very small interface buffers on the 3560x - perhaps that is the cause.

Could anyone clarify for me?

[dominic.caron]

The ASIC on the 3560X are line rate. Since you have output drops, at some point in time, you are sending more then 1 Gbps to a port. The buffer can take a little burst but will start drop at some point. You might be able to optimise your queues and thresholds.

If you look at it by interface, you will see where you are dropping frame.

[Joseph W. Doherty]

Disclaimer

The    Author of this posting offers the information contained within this    posting without consideration and with the reader's understanding that    there's no implied or expressed suitability or fitness for any  purpose.   Information provided is for informational purposes only and  should not   be construed as rendering professional advice of any kind.  Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In    no event shall Author be liable for any damages whatsoever  (including,   without limitation, damages for loss of use, data or  profit) arising  out  of the use or inability to use the posting's  information even if  Author  has been advised of the possibility of such  damage.

Posting

As Dominic's post notes, you can drop frames when you send faster to an egress interface than it can physically transmit.  If the hardware wasn't line-rate, you might see lost frames before the egress interface hits full capacity, but again, think its the former not the latter.