GateHouse Telecom: Global Xpress Link Emulator – Congestion

GateHouse Telecom: Global Xpress Link Emulator – Congestion


Hello and welcome to this video in which I
will explain the congestion feature in the GLE. Congestion is what specifies what other traffic
than your own exist in the cell we are emulation. And this congestion will limit the amount
of bandwidth available for your applications. You remember the charts showing the data usage
for your applications but you can actually see what other users are using as well by
hitting this other button the red line in the chart here is for other traffic. You can see it quite bursty goes up and down. I have set the GLE to use a fixed bandwidth
channel we’ll wait a second. So your application and users have to share this one. In this point of time other users are transmitting
quite a lot and your application just get the CIR at this point your application most
likely does not require any data at all so the others will get a little bit more. At other times they share it. There are two types of congestion. What we call background load and burst load. Right now there is no background load, but
some burst load. Background load is an easy and simple way
to set up congestion. You simply specify how much data other users
will use and background load has highest priority in the cell so it will simply limit how much
is available for your application. I can for instance remove the burst load and
set the background load to 75 percent. which is 6 Mbit per second at most and the
medium I can set to 50 percent, 4 Mbit per second and at last 25 percent which cause
1-2 Mbit per second. And again I hit apply to use this parameter
and on the front page I can see the effect of this, and most probably you should see
charts that grows from 2 to 6 Mbit per second and varying in some random way. And again you can see the sum of these two
charts should not go beyond the 8 Mbit that I have specified for the cell. You can see in this part the background load
has used more than 4 Mbit so your own application cannot get the 4 Mbit that is your MIR. At this point the background load is below
4 Mbit so your application can get the 4 Mbit MIR. On the congestion tab we have a simulation
down here which gives you a quick view on how would these parameters influence your
chance of getting a certain bandwidth. On these charts we have the bandwidth here
and here we have a probability to get that bandwidth so we can see that the chance of
getting 2 Mbit per second is close to 100 percent which is expected because the maximum
is 6 Mbit and the channel is 8 Mbit so we should always be able to get 2 Mbit. On the other hand the chance that we get 4
Mbit is approximately 50 percent which is again expected as the medium load for background
is 4 Mbit. The probability to get the MIR level is close
to 50 percent the CIR level is then the probability that we get the CIR and these are the figures
you can see here for both uplink and downlink. The other type of congestion is burst load
which is a more realistic congestion and I will demonstrate it now. First I will set the background to 0, it is
of course possible to have both kinds of congestion at the same time but for demonstration purposes
I will remove the background load. Then I will create a new group of burst loaders
you can have all the burst loaders that you want. Burst loaders will respect the priority of
data so burst loaders might have lower, higher or same priority as your own. On the subscription tab I can see that the
priority for my VLAN that I am using is 10 so I will set a group of users to have the
same priority I could say that there is three users at most and minimum. These users I set to transmit burst of 4 Mega
byte and we can put some deviation on the burst and say that they get to transmit three
bursts per minute and all these three users could have a MIR of 4 Mbit and a CIR of 1
Mbit. And hit apply to see the result. And for our VLAN 1024 you can see the that
it would look like this. MIR level is this case 32 we still have CIR
level of 100 and on the front page we can see the result in the end. You can see these bursters here and as they
have same priority as our own users they will have to share. We remember that we have at the most three
users so at this point in time this is probably two users bursting and our users so they will
have to share so our users get just below the 3 Mbit and the to burst users will get
just below 6 Mbit and in total that is 8 Mbit. I can set the priority of burst loaders to
a higher priority a lower number. And that should have an influence on the charts
here. because now they have higher priority so they
will sometimes get higher bandwidth and limit your bandwidth more. And as for the channel and the subscription
you can save and store these parameters in sets. I think this concludes the demonstration of
the congestion feature. Thank you.

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