Video Transfer With Bandwidth Limitation

[teleport11]

Hi,

I am using 2 Cisco 3650 Switch for location A & B on lease line, the problem is from location A i need to transfer the Video to location B with an bandwidth restriction of 2 Mbps where as my input to location A is 4 Mbps. I have used the commands as 

ip access-list extended ACL_SLAP
 permit ip any any
 
class-map match-all CLASS_SLAP
  match access-group name ACL_SLAP

policy-map POLICY_SLAP
  class CLASS_SLAP
    police 2000000 

interface GigabitEthernet0/2
 service-policy input POLICY_SLAP

With this i am able to strict the bandwidth, but my Video is not coming properly its giving me the freeze frames (Video is not smooth). Can you please help to resolve this.

Thanks in advance

[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.

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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

If the video needs more than 2 Mbps, policing it will cause issues, such as you note.

Some video streams will automatically reduce their bandwidth demand (and their picture quality) when they determine packets are being dropped; some don't.  For the latter, either you need to insure they have the bandwidth they need or you need to, if possible, have the video transmitter send using less bandwidth.

[teleport11]

Hi Joseph,

Thanks for the time, but issue is we can't reduce the Video bandwidth from the source hence has to be controlled at the Cisco Switch end to forward the same to destination. Is there any other way which you can suggest.

Thanks & Regards,

[e.ciollaro]

Did you try using shaping instead of policing ? Not very confident it can solve your problem but if your video is something like a video on demand and not like a videoconference, maybe shaping could help. Using policing, traffic that exceeds  the threshold is dropped (remote site never receives that packet causing video freezing). Using shaping packet are not dropped and, considering that videostream software usually has some kind of buffer, may be it could be better.

Obviously these has sense if your videostream has not a constant bit rate, in that case the only way to improve video quality is to reduce the required amount of bandwidth chaning codec or increase bandwidth allowed for video.

Bye,

enrico

[teleport11]

Hi Enrico, Thanks for your valuable time

My Video is not VOD or video-conference its 24x7 content (SDI video goes to Enc and from Enc i get TS output as IP). Now do you think shaping will work or do you have any shaping example to tryout.

Thanks & Regards,

[e.ciollaro]

Well, I don't know much about video technologies so can't say it shaping will work or not; as it is a 24x7 stream I suppose it has a constant bit rate, if so shaping doesn't help; it could be useful in case of traffic burst but if videostream has a constant bit rate, switch  buffer are going to overflow and traffic will be dropped.

In any case you you want to make a try look the following URL, 

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3650/software/release/3se/qos/configuration_guide/b_qos_3se_3650_cg/b_qos_3se_3650_cg_chapter_010.html#concept_53FE327EBFE141D88A4ABEF889E143ED

[teleport11]

Hi,

With shaping also its not working.

[e.ciollaro]

So the only things to do is giving more bandwidth to the stream (or reduce the required bandwidth)

Bye,

enrico.

[Joseph W. Doherty]

Often, yes.

If your IOS version allows, sometimes increasing the queue depths on the shaper might do the trick too.

[e.ciollaro]

Hi Joseph, good idea but just if the stream bitrate isn't constant, otherwise sooner or late buffer will overflow,  am I wrong ?

Bye,

enrico

[Joseph W. Doherty]

Correct.  If the stream rate is constant, you need very little buffering.

If the stream rate is variable, you need to buffer the peaks but still have enough bandwidth for the average.  The closer your average is to your available bandwidth, the more buffering you'll need.

[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

Enrico's suggestion about shaping rather than policing is excellent!  However, it requires the receiver to buffer and it also requires that your average transmission rate is within your bandwidth allowance.  If neither are true, we're back again to what Enrico and I have already described, i.e. either you need to allow more bandwidth for video or you need a video transmission that uses less.

Otherwise, video is like VoIP, it just won't work well without the resources, such as bandwidth, it requires.