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New Member

QOS Queueing

When enabling a queueing tool on an interface(Serial in particular), IOS reduces the TX Queue from some value (16) to a small value (2).i.e. TX queue accpets 2 packets in the TX queue.. Does enabling queueing increase delay from the output queue to the TX queue, if congestion does not exist? Creating any noticeable jitter?


  • Other Collaboration Voice and Video Subjects

Re: QOS Queueing

Per Cisco, "The smaller the value (TX queue value), the less impact the TX Queue has on the effects of the queuing method." In other words, if you have a large value for the TX Queue, many of your packets would never hit the software queue enabled on the interface. You would lose benefits like prioritizing voice packets over data packets and link fragmentation and interleaving (LFI). Queuing is the reccomended best practice for voice networks. I understand your question regarding increased delay moving a greater number of packets from the software queue to the TX queue. The delay should be negligible and the benefits of using queuing for your voice traffic far outweigh any negative impact from this delay. Queuing tools are used to decrease jitter for delay sensitive traffice like voice. It's true that this can increase delay for your data traffic, but it is much more tolerant of this delay.


New Member

Re: QOS Queueing

Hi Brandon,

That is what I thought too... I just wanted to throw it out there..


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