[Cake] Query on ACK

[Jonathan Morton]

> On 7 May, 2020, at 9:44 am, Avakash bhat <avakash261 at gmail.com> wrote:
> 
> Thanks for the quick response. I also had a followup question. 
> 
> If the ack filter adds the new ack to the tail of the queue after removing an ack from the queue, won't it be starving the ack? 
> The replaced ack was much ahead in the queue than the ack we replaced at the tail right?

No, if you are doing this on enqueue, then you are comparing the new ack with an ack immediately preceding it in the same queue, which will also be at the tail.  And if you are doing it on dequeue then both packets were enqueued some time ago, and both are already due for delivery very soon.

In general, the second packet is delivered sooner, in place of the first one that was removed.  This means it reduces feedback latency to the (forward path) sender.

 - Jonathan Morton