- I want to take a look now
at some common troubleshooting steps
for your wireless network.
As with any troubleshooting procedure,
the more information you have,
the better you'll be able to pinpoint a specific issue.
One of the first questions to ask is,
are the issues reported by a single user,
or by many users?
If this is a single user issue,
this points to something with the wireless client itself.
If its more of a widespread problem,
then obviously,
you'll want to take a look at the controller side of things.
There are three basic things required
for a successful association
between a client and an access point.
First,
the client must be within in the RF range
of an access point.
If they are in an area with little or no RF signal,
this is going to cause a failure.
Second,
the client must be able to properly authenticate.
Are their network credentials valid
or being entered correctly?
And so on.
And finally,
the client should be receiving
a valid IP address from the network.
Obviously there are many user and hardware issues
that can be at fault here on the client itself,
maybe that's failing hardware on a laptop,
or maybe that's just a user entering incorrect credentials.
And you'll want to check those things out first.
Here,
we're going to specifically examine some troubleshooting steps,
within the Cisco wireless lan controller environment.
Here, I'm logged in to my own wireless lan controller,
in my lab environment.
Let me preface this by saying that,
I don't have any clients here in my lab,
and also that
your GUI interface may look differently
depending on which wireless controller model
that we're using.
In general all the same options are there,
but they may be in a different place,
or look slightly different in the menus.
If we're starting troubleshooting
on the client's side of things,
an easy way to start narrowing down the issue,
is first by obtaining
the MAC address on the affected wireless client.
Using that,
we can perform a search here,
from the summary window if we go down
to the client menu at the bottom left.
I'm told you can see that there are no clients
in my lab environment.
But at the top notice there is a current filter listed.
And that's currently listed as none.
In this area, this will allow us to search
by a specific MAC address.
If we click the change filter button,
you'll see that we can choose the MAC address,
we can choose many other things here as well.
You see the username,
the radio type, the device type.
Many other things depending on your needs.
Once we do a search by the MAC address,
on the subsequent window,
you'll something that looks like this.
You'll see a client properties view,
with lots of helpful information about this client.
One really helpful area,
is the Policy Manager State section
that you see highlighted here.
This state with help you identify
exactly where the problem is
with the association
between the client and the access point.
Its good to understand what these states mean,
so that you can troubleshoot better.
And we have eight potential states.
We have the start state,
where the association process is just beginning.
We have the AUTHCHECK state,
which is where the client
must pass a layer two authentication policy.
We have the 802.1X required state,
which is where the client must pass 802.1X authentication.
We have the layer two authentication complete state,
which means that at this point,
the layer two authentication has been successful
with the client,
and the layer three policies can begin.
We have the WEP required state,
meaning that WEP encryption is configured
and the client must authenticate.
We have the DHCP required state,
which is the where the client is obtaining an IP address,
and the controller is making note of that
in its own database.
We have the WEBAUTH required state,
meaning that web authentication has been configured,
and the client must successfully
authenticate in this manner.
And finally,
we have the RUN state.
Meaning that the client has passed all layer two
and layer three policies successfully
and that they are fully operational on the wireless network.
The Policy Manager State
will list the current state of the client,
which can indicate whether or not
they are stuck in the middle
of an association process with an access point.
For example,
if the client is stuck in the off check state,
that means they are unable to provide
the authentication necessary to join the network.
So this is very helpful information
to help pinpoint client issues.
Now obviously its ideal
that each client should end up in the RUN state.
If a client is consistently shown in a state other than RUN,
this indicates they're having a problem
passing a particular state shown in the output.
Recall our previous discussions,
of received signal strength indicator,
or RSSI.
And signal to noise ratio, or SNR.
Knowing about these two topics,
we can find some very helpful information inside this GUI.
If we click on the Cisco CleanAir menu,
on the left
you can see that it's going to show us
our available radios here,
our 802.11 radios.
And we have two options under each.
We have interference devices,
and air quality report.
Again those options may vary
depending on your model of control
or you may have more options here than I do.
The interference devices report, if we click that,
that's going to identify a device that is found to be
problematic and causing interference on the network.
We can see an example of that here.
Where the device type is listed
and the effected Wifi channel.
We also see the detected time,
so in other words
when was this problem last seen on the network.
And we have a severity rating,
which ranges from zero to one hundred.
With one hundred being the most severe.
You can see that these are both very low,
so they aren't prone to be problematic
in this particular example that we have on screen.
We also see the RSSI which we've mentioned earlier.
This would be an area to check
if you're having a more widespread issue.
Where multiple users
are reporting problems on a particular access point.
If we scroll down
we can see a visualization of this area,
with a channel utilization graph,
and an RSSI graph.
Again, very helpful information to see
what's going on in your network.
Underneath the interference devices menu,
we also have an air quality report menu.
And again,
here we have one for each of those available radios.
You can see an example of this on screen
where we have the name of a particular access point,
followed by some information.
We see that the average and minimum air quality ratings
are at ninety-nine which is very good.
Air quality is rated from zero to one hundred,
with one hundred of course being the best.
By the way,
by CleanAir, we simply mean that there is
little interference with our wireless signal propagation.
We also see the option for an air quality graph.
If the reports of issues seem to be more widespread,
this can indicate an issue with an access point itself,
rather than the client.
One common issue is simply a defective
or dying access point.
A non-functional AP within the network
can create a coverage hole
and leave specific users without any wireless capability.
If we click on the wireless menu at the top,
we can choose the all AP's option on the left,
and that's going to show us information
about all of our access points.
Including the up time,
the operational state,
the number of clients they have associated,
and many other helpful statistics.
You'll want to watch out for AP's that may be
overloaded with clients from this window.
If they have too many clients associated,
that can certainly cause an issue.
Other areas that may be of assistance,
is the Rogues menu,
if we go back to the monitor screen.
You can see the Rogues menu on the left,
we can expand that and you can see that we have rogue AP's
and rogue clients
as well as friendly devices,
so we would be able to see all of that.
And of course there's much much more to be found here
in the troubleshooting options.
Much more than we can cover
or much more than we even need to cover in this video,
but I did want you to be aware of some of the common
starting points for troubleshooting
from a wireless lan controller.
The great thing about having a centralized device like this,
with lightweight access points and a great GUI interface,
is that it makes seeing these statistics
and troubleshooting everything
much much easier for us, as a administrators.