Well, queuing is a very foundational topic when it comes to quality of service.
So let's take a moment to make sure we've got all of this down before moving on
.
First up, how many queues are supported by each of the following methods?
So let's just think through what all of these are.
So weighted fare queuing, this is where all of the traffic flows get mapped
automatically
to a different queue.
And so that's going to be the largest number, which is 4096.
Safety queuing is the one that we have those strict priority queues already WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Safety queuing is the one that we have those strict priority queues already
built.
They're the high, medium, normal and low.
And so there's only four of those.
CBW FQ low latency queuing that supports up to 256.
Again, it's platform dependent, but we do support up to that much on certain
platforms,
custom queuing that will give us 16 different queue options.
And first and first out, that is just a single one.
So that is the how all these different queuing mechanisms come together and
understanding
that will help to make sure that we understand how the queues work. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
that will help to make sure that we understand how the queues work.
Now what does queuing enable for network traffic?
Again, this is driving home the point of what we're trying to accomplish here.
If we think back to the conveyor belt analogy, if I just have a single stack of
boxes, I'm
just going to grab the first box that's there and chuck it onto the conveyor
belt.
And so that's the concept of that first and first out.
So we could say, hey, if there's a priority box somewhere in that stack, then
you should
go get that.
But how am I supposed to know where that is and how am I supposed to know it's WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
But how am I supposed to know where that is and how am I supposed to know it's
even
there?
Well, what I can do is I can create multiple queues that allows me to see very
clearly
what is in each level of priority, whether that's just one priority type of
queue or
whether we have lots of different traffic classes like we do with networking.
And so the idea here is not to send more packets because we can't do that.
We can't increase our bandwidth.
Our guarantee traffic is never dropped.
But what we can do is we can now send one packet over another. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
But what we can do is we can now send one packet over another.
And we don't have that capability with first and first out where we just have
to grab the
next packet.
Now why isn't the low latency queuing mechanism built on strict priority que
uing?
Why do we have that bandwidth limit in place?
Remember, this is all about the concept of traffic starvation.
We want to prevent starving non priority traffic, whether that's a misconfig
uration because
oops, I put something that's a very large traffic flow into a queue that now
has strict
priority. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
priority.
Or if we just have a bunch of voice traffic all of a sudden, we don't want that
to make
it so nobody else can access the network.
And so it does seem a little bit backwards to say, oh yeah, we care so much
about voice
over IP.
But in some cases we do want it not to be prioritized, but it does make sense
when we
think about it from a starvation perspective, which is why we don't want to use
priority
queuing like we talked about with those four strict priority queues.
And yet we do need that priority mechanism in place. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And yet we do need that priority mechanism in place.
We just need to make sure that it can't starve other traffic flows.
So that is again, a foundational set of topics here talking about queuing the
creation of
multiple queues, controlling policy is going to require us to have different
queues so
that we can service packets in the order that we want to service them in.
I hope this has been informative for you and I'd like to thank you for viewing.