[Cake] total download rate with many flows

George Amanakis g_amanakis at yahoo.com
Mon Nov 13 21:49:53 EST 2017

Dear David,

I agree. My point is that currently ingress mode seems to be dropping 
more packets than necessary to keep senders from bottlenecking the 
connection (when there is a large number of concurrent flows, >8). And 
right now, ingress mode is the only mode that achieves this in 
situations such as Windows updates.


On 11/13/2017 9:08 PM, David Lang wrote:
> Ingres and Egress are fundamentally different due to the fact that in 
> ingress mode you are having to throw away data that has successfully 
> traversed the bottleneck (deliberatly wasting your limited resource 
> now to avoid having senders bottleneck the queue on the far side of 
> the link)
> in Egress mode, you aren't doing that, and so you can get much closer 
> to the actual bandwidth.
> In addition, in Ingress mode, you are always working via second-order 
> effects, you can't slow a transmission directly like you can in egress 
> mode, all you can do is drop packets and wait until the sender 
> notices, retransmits and slows down. Egress has full control of the 
> queues and can send things in any order, and may be able to 
> continually fill the pipe and avoid any timeouts and retransmissions 
> (if the flow is short enough)
> David Lang

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