Lastly, we want to cover the concept of adaptive QoS.
Adaptive QoS addresses a problem that we have with SD-WAN that we don't really have with traditional networking.
Namely, how do we apply quality of service in a way that makes sense with our internet circuits?
And this specifically is going to apply to our shaping conversations.
So recall what we said about shaping.
If I've got a wide area network circuit, and maybe this is, let's just say it's 20 megabits per second, and I have a 100 meg link.
I can't just send 100 meg of traffic. I have to shape this down to 20 meg by deciding which traffic I want to drop.
Technically, I don't have to. If I send 100 meg of traffic, then it's going to get policed by the policer that's running on the service provider router.
But it will just drop whatever traffic it wants, so we don't want that.
We would rather make the dropping decisions.
This works out really well when it's stable.
And with our traditional wide area network providers, it is stable.
It's a 20 meg MPLS circuit or whatever it is.
Maybe it's LIT fiber service or something like that. Maybe it's a Metro Ethernet.
But if they provide us with 20 megabits per second, it is typically very stable.
If it's not, then it's probably not a very good service.
And internet circuits are not so stable.
So what we're really talking about here is the possibility that I get an internet service provider to provide me with a circuit.
And let's say they also provide a 20 megabit per second service.
And so I'm connecting this at 100 megabits per second because Ethernet, I mean, it's either 100 meg or it's 10 meg or it's a gig.
I can't connect in a 20 meg Ethernet port, but I can connect 100 meg and I can shape it down to 20 or so we think.
The problem with this is internet bandwidth tends to go up and down like crazy depending on current network conditions.
For example, if it's 3 p.m. and all the kids are home at a local internet hub is receiving all kinds of traffic from the kids who have come home from school.
Well, we might be in a little bit more of a downstate versus at 8 a.m.
It's probably even more than 20 megabits per second.
So let's say that our internet currently is at 10 megabits per second.
And so we've got a 10 megabit per second effective SLA at that point.
Shaping it down to 20 meg is not going to be super useful.
We're still going to see a lot of traffic just get dropped out because of internet buffers.
Conversely, what if our internet is actually seeing like 30 megabits per second this day?
Because we actually could leverage this better.
So all of this leads to the concept of adaptive.
I already wrote it out, didn't I?
Adaptive quality of service.
And as the name implies, we're going to adapt to current conditions.
So when I'm configuring my shaping, I'm going to give it a range.
That's the important part.
Normally, I would just say, hey, shape it to 20.
But instead, now what I can do is say, hey, we're going to shape it to 20, but we're actually going to give it a range.
And that range is maybe, I used 10 and 30 down here, so let's just keep that.
We'll say we'll create a range of 10 to 30 megabits per second.
And so the idea here is now I can allow my edge to determine what network conditions are like.
Because again, remember, it's running BFD.
It sees what is happening.
It measures latency.
And so it can start to shape maybe more at 25 meg, if it's a good day, or 15 meg, or even all the way down to 10 meg,
if we're having a really bad situation on the internet circuit.
And if we're properly shaping, regardless of what the value is,
then our voice over IP traffic will always be prioritized.
And that's very important if we're going to leverage our internet circuits in our SD-WAN environment
for critical traffic like voice over IP,
which is one of the fundamental goals of deploying SD-WAN into our environments.