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Transcript for this video

Welcome back to our Mini Maxwell and Maxwell G video series.

In our previous videos, we showed you how to use impairments, filters, and bands to emulate basic  network conditions.

In this video we'll show you how to use those tools to emulate a network with multiple concurrent users.

In today's world of apps and appliances, the typical home or home office often has several users who are simultaneously using a link to the Internet.

For example, consider a home where the parents are streaming a movie from HBO, while one child is watching a show on Netflix, and another child is engaged in a Skype video chat.

How well will all that work?

If your app will be used in a home environment, you'll want to test and evaluate your app under all those conditions by emulating that environment in your lab.

To test this kind of thing in the lab, we'll need three user devices: one to stream from HBO, one to watch Netflix, and one to do Skype video.

We'll put each of these devices onto the same IP subnet, just like they would be at home. We'll use a simple ethernet switch to represent this home IP subnet.

The wired devices will connect directly to this switch. For wireless access, we can use a wireless access point in its most basic access point mode--not a router, NAT, or firewall.

The wired side of the access point will be connected to the switch.

This wireless access point should have a unique SSID and try to avoid using a radio channel that's being used by other wireless devices.

Our wireless user devices should be configured to attach to that SSID.

The wireless could be open or secured.

The security of the wireless is not relevant to our test except insofar as we don't want others to find our wireless signal and use it.

We can then attach one of the ports of that switch to our lab network.

However, rather than using a direct ethernet cable to attach the switch to our lab network, we will interpose a Mini Maxwell using an ethernet cable to attach the LAN-A port on the Mini Maxwell to our lab network and another ethernet cable to attach the LAN-B port to our ethernet switch.

This means that packets flowing to our three devices will enter the Mini Maxwell via its LAN-A interface and exit via the LAN-B interface.

Then we should power up the Mini Maxwell, giving it a minute or two to boot and initialize.

As a test, we should now go to the Mini Maxwell web user interface.

Make sure the Filter Map is cleared, and then set the DROP value of both sides of the Mini Maxwell "Bands & Impairments" screen to a value of 100%.

This should cause all traffic flowing to and from our client machines to stop.

We can check this in the traffic graphs, or check the devices directly.

Once we confirm that traffic is stopped, we should remove the 100% DROP and confirm the devices have become operational again.

Next, collect the IP addresses being used by each of the user devices.

This may take some time, and the procedure will vary from device to device, so for brevity's sake, we'll skip that process.

For our next test, we'll be impairing only traffic flowing to each of the client devices.

We could also do this to traffic flowing from each device, but, for the simplicity of this video, we'll focus on inbound traffic.

Once we have the IP addresses of the devices, we'll need to isolate each device's traffic into its own band.

This is where filters come into play.

We'll discuss creating custom filters in a future video, but for now we've created three filters that separate the TCP traffic for each device.

In order to use these filters, we go into our Filter Map to activate each one of them.

Since we're concerned here only with traffic flowing from the Internet to our client devices, we'll only apply these filters to the LAN-A to LAN-B direction of packet flow.

Remember, our connection to the Internet is on the LAN-A side of the Mini Maxwell, and our user devices are on the LAN-B side. Activate the filter for the parents' HBO viewer to classify those packets into "LAN-A to LAN-B" Band 1.

Activate the filter for the client that is watching Netflix to classify those packets into "LAN-A to LAN-B" Band 2.

And activate the filter for the client on the Skype video call to classify those packets into "LAN-A to LAN-B" Band 3.

Don't forget to submit this.

Now we need to check that we have the filters properly in place.

So we go to the Bands & Impairments page and we go to Band 1.

We should set the LAN-A to LAN-B side to have a drop of 100%.

This should cause the HBO viewer to stop.

If it stops, then the impairment is functioning correctly and we can set it back to 0%.

If it doesn't stop, then we did something wrong in the setup.

We should repeat this check for the Netflix viewer on Band 2 and the Skype machine on Band 3.

Now that things are set up and functioning correctly, we can dial in the impairments that we want to apply.

Here are some possible scenarios: Scenario A: Let's give a total inbound bandwidth of 6 Mbits/s, a typical value for a home ADSL, and divide that equally among the three clients.

To do this, we go into the Bands & Impairments page and set a value of 2,000,000 into the Rate Limiter for the LAN-A to LAN-B side of Bands 1, 2, and 3.

We can play with these allocations, keeping the sum at 6,000,000, to see how each of the applications behaves when its inbound traffic is reduced.

When done, don't forget to reset the impairments to the default so that we have a clean slate to do other scenarios.

Scenario B: We can assign different packet delay values. For example, add 100 milliseconds to the HBO stream, and for fun, dial in 75ms of variation.

Use the "None" distribution, which will give a uniform distribution between 100 minus 75ms and 100 plus 75ms.

We can impose similar delay values for the other clients.

We can enable packet reordering to see what happens.

Remember to use the Submit button; changes are not made until you submit them.

Scenario C: Or we can dial in some basic packet loss.

For example, tell the Mini Maxwell to drop 10% of packets and see how that affects performance on our various devices.

These are just a few of the endless potential scenarios that you can test using the Mini Maxwell and the Maxwell G in conjunction with custom filters.

Testing your application under all these scenarios will help you learn how to optimize its performance for the home environment.

Thanks for watching, and we hope to catch you next time.


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