Hi guys could you please help me. I want to understand the fundementals of Queuing but I am stuck on the difference between Active and passive queues. Firstly, what is an active queue? Secondly, what is a passive queue? Thirdly, what's the difference between the two? And finally, which out of the two would be the most preferable or better type of queue to go with?

I want to know the meanings of active queue and passive queue and the main differences between the two. What does it mean when you configure a network queue to be active or passive?

Any help you do give would be much appreciated. Thank You.

  • 1
    Please give us some context for your question.
    – Ron Maupin
    Dec 6 '18 at 0:20
  • 1
    That's not really what I meant. I mean in what context are you seeing active/passive queues that prompts your question. I am not familiar with active/passive in relation to queues.
    – Ron Maupin
    Dec 6 '18 at 1:33
  • 1
    You'll need to tell us which device you're referring to. Likely, this active and passive differentiation is vendor-specific.
    – Zac67
    Dec 6 '18 at 5:22

The fundamentals are pretty simple:

  • In passive queueing the network device just discards packets if an output queue is full
  • In active queueing the network device uses algorithms to work out which packets it should drop from its queue

The issue with refuse-latercomers is that it has unexpected consequences of synchronisation of flows and problems such as "congestion collaps". What kinds of active management a given device has depends on the exact device.

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