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New Member

3560X pps throughput query

Hi,

I would like to know some performance details of the 3560X switch in the following setup:

  • Running/participating in Layer 3 routing eg OSPF
  • Only 2 gigabit interfaces connected; one to an SP and the other into the corporate network
  • The traffic being exchange is only voice, G711 and G729 packets

Based on the above I have the following queries:

  • Is the 3560X switch capable of handling the throughput of this type and in this setup? Given that the voice packets are quite small in nature, there will only be two interfaces in use and the nature of switches is to do everything in hardware (eg. ASICs)
  • What is the maximum packets per second for a single 1 gigabit interface?
  • Would this deployment benefit from changing the SDM Templates to routing?

I have found the 3560X has the ability to handle 65.5 mpps via the data sheet, but I assume that this is the complete system aggregated.

Regards,

Vic

  • LAN Switching and Routing
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Super Bronze

3560X pps throughput query

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


Victor Correia wrote:

HI,

So, how many calls were you intending to pass across a gig interface?  What's acceptable queuing delay?

To keep calulations easy, say there is a 1000 agents, so it would need to handle 1000 calls at any one time, and those agents are locate 5000km away with about 100ms one way latency.  So the lower the queuing delay the better.

Regards,

Vic

All right, than that would be about 100 Mbps for G.711; shouldn't be a problem for a 3560X.

6 REPLIES
Super Bronze

3560X pps throughput query

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

"I have found the 3560X has the ability to handle 65.5 mpps via the data  sheet, but I assume that this is the complete system aggregated."

For 24 port, correct?

"Is the 3560X switch capable of handling the throughput of this type and  in this setup? Given that the voice packets are quite small in nature,  there will only be two interfaces in use and the nature of switches is  to do everything in hardware (eg. ASICs)"

It should be.

"What is the maximum packets per second for a single 1 gigabit interface?"

Wire-rate Ethernet, for minimum sized packets, required pps rate is 1.488 Mpps.

"Would this deployment benefit from changing the SDM Templates to routing?"

That depends.  Changing the template changes TCAM resource allocation.  Changing to "routing" allows for more routes to be in TCAM.  This doesn't make processing any faster but it does avoid making processing much slower it TCAM resources are exceeded.

New Member

3560X pps throughput query

Hi Joseph,

Thanks for the feedback.

Yes, it is a 24 port switch.

My concern is the buffers may be to small to handle that type of traffic in a sustained manner, say 20Mb of G711 traffic.

Victor

Super Bronze

3560X pps throughput query

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


My concern is the buffers may be to small to handle that type of traffic in a sustained manner, say 20Mb of G711 traffic.


Ah, an excellent concern.  However, for something like VoIP, you don't want to oversubscribe the available bandwidth, i.e. if you need to (excessively) buffer VoIP bearer packets, you likely don't have enough bandwidth.

That  noted, since devices often implement queue limits based on  packets/frame count, small frames/packets might exceed queue limits even  through there is adequate buffer space.  So, you might need to adjust  logical queue limits.

Since G.711 is sort of CBR, you can push the link/interface to very high utilization, predicting average queue depth assuming a M/M/1 solution.

For example,  let's assume our G.711 packets are 200 bytes, and we don't want to  exceed 10 ms.  Also assume we're using a gig link.  First we calculate  the number of packets that use 10 ms on a gig link, each 200 bytes.  I  calculate 6,250 such packets (or 1.25 MB).  M/M/1 predicts 99.985 utilization would average 6,665 in the queue.

Also assuming about 87.2 Kbps per G.711 call, a gig would support about 11 thousand calls.

So, how many calls were you intending to pass across a gig interface?  What's acceptable queuing delay?

New Member

3560X pps throughput query

HI,

So, how many calls were you intending to pass across a gig interface?  What's acceptable queuing delay?

To keep calulations easy, say there is a 1000 agents, so it would need to handle 1000 calls at any one time, and those agents are locate 5000km away with about 100ms one way latency.  So the lower the queuing delay the better.

Regards,

Vic

Super Bronze

3560X pps throughput query

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


Victor Correia wrote:

HI,

So, how many calls were you intending to pass across a gig interface?  What's acceptable queuing delay?

To keep calulations easy, say there is a 1000 agents, so it would need to handle 1000 calls at any one time, and those agents are locate 5000km away with about 100ms one way latency.  So the lower the queuing delay the better.

Regards,

Vic

All right, than that would be about 100 Mbps for G.711; shouldn't be a problem for a 3560X.

New Member

3560X pps throughput query

Hi,

Thank you for the information; it provided me the direction I needed to move forward.

Regards

Vic

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