cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
4168
Views
5
Helpful
2
Replies
Highlighted

QoS -- VoIP -- SP vs WRR

Dears

I hava a question and would like your assitance please

If my BW is larger than traffic I receive (voice + Internet traffic), in this case is it a must to put voice traffic in SP queue or mapping to different WRR queues would be fine ?

I know it will be better to put voice in SP queue and internet traffic in different WRR queue, but I am just asking from learning point of view

One opinion says says it is not a must to have SP queue ; i.e. both can be in different WRR queue as long as BW is larger that traffic I receive as QoS will only works in case of congestion

Another opinion says I should use SP queue, cause even if there is no congestion a large packet may already be in queue being served so during that time voice packet has to wait till schedular finishes serving this packet

What do you think ?

Many Thanks

Sherif Ismail

2 REPLIES 2
Highlighted
VIP Expert

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

One opinion says says it is not a must to have SP queue ; i.e. both can be in different WRR queue as long as BW is larger that traffic I receive as QoS will only works in case of congestion

Is a SP queue always a must?  No, but it helps to deal with jitter that can arise even in cases where bandwidth is not oversubscribed.

Yes, QoS only engages when there's congestion, but congestion is whenever there's queued elements.  "Larger" bandwidth, alone, does not guarantee there won't be queuing if there's multiple ingress streams, as more than one element can arrive at the same time.

Another opinion says I should use SP queue, cause even if there is no congestion a large packet may already be in queue being served so during that time voice packet has to wait till schedular finishes serving this packet

It's not quite as you describe.  Scheduler determines next item to transmit, once selected and it's being transmitted your stuck waiting on it regardless of whether there's a SP queue or not.  If this is an issue, and it can be, the solution is to not allow large items (as a single physical frame) to be transmitted at all.

SP queue insures whenever the scheduler is selecting, SP queued elements are selected first.

Highlighted

Many Thanks Joseph

Content for Community-Ad