I've got two switches here that are trunked together through one single trunk line and well I've got
a problem.
I have so many devices working on these two switches, well clearly they're not plugged in right now,
but normally they are, that my trunk line is getting overwhelmed and I need to come up with some way
to increase the bandwidth of my trunk line.
Now I guess I could buy new switches that were higher speed but I'd like to keep using what I have.
So what we're going to do is we're going to do something called port bonding.
Now Port bonding has about a bazillion names to it.
It's called Link aggregation, channel bonding, port trunking, NIC trunking, NIC teaming.
There's a million different names for this but CompTIA concentrates on the term port bonding and that's
what I want us to concentrate on.
So what we're going to be doing here is we're going to go through a process of taking two ports on each
one of these devices and by the way this is not limited to two, you can do with more than two if you'd
like.
And they're going to work together as a team and in essence they will act as one single higher speed
port.
So right now here's my setup I've got this one trunk right here and I'm going to set up two more ports
and I'm going to make two ports on each one of these switches work together and make all this happen.
So to do that we're going to have to go in.
And this is also an opportunity for us to take a look at some Cisco IOS commands while we're at it.
So what I'm going to do is, you can see I'm already connected right now to one of the switches and I
know his IP address.
So I'm just going to fire up putty and I'm going to connect to him and show you how this all happens.
All right.
So here I am I'm going to start up putty. So I got putty running.
Let me do the password.
Type in the right password.
There we go.
I need to warn you network plus is not going to test you on IOS.
However if you're doing a lot of stuff with switches you're going to be working with a lot of Cisco
stuff.
Most of the heavy lifting we do is in the command line interface which is IOS, so get used to this stuff.
I figured this would be one great example to show you.
All right.
So what I'm going to do here is I'm going to go onto each switch and I'm going to take Port 23 and
24 of each switch
and I'm going to make them into a group. Now in the Cisco IOS world the first thing we do is we make
a group and then we go in and we assign the individual switch ports to that group.
So follow the bouncing ball as I type in these commands.
So I have to type in config terminal to get things started.
Now the first thing we're going to do is interface
port channel 1.
So basically we've just told the switch to create a group and they call it port channel for us to connect
these two physical ports together OK.
Now what imma do is assign each of these to it.
So we'll go in.
So we're going to make sure it's a trunk.
Then we go actually into the switchboard itself and I'm going to start with 23.
All right.
And now I'm going to assign it to that group
OK.
Now you see I've typed in channel group one mode.
Now the protocol we're going to be using is called LACP.
There were earlier protocols but this one pretty much I could connect switches from different brands
and everybody to make this work.
So what we need to do is we need to say is this port going to be an active or passive or whatever type
of port we want.
I'm going to say active.
That basically means if I connect you to something look for another port that's ready to do some port
bonding. So I'm going to just go ahead and set him as active.
OK that's done.
So what I need to do now is basically repeat the process. So this time we're going to go so I'm going
to the other port.
All right.
So I've now set up both of these ports to be part of that group.
What I'm going to do now is go ahead and get the other ones set up and then we're going to come back
and actually see how all this works.
OK.
Well if I've done it all correctly I'm going to go ahead and plug in another crossover.
And let's see what happens.
So I did it for 23 and 24 on both sides.
And if I'm doing it right we should see some lights begin to kick on and we now have port bonded our
ports 23 and 24 on each one of these guys. So it should be working. And the best way to find out is to fire up
putty and take a look.
OK so I've got putty here and it's already logged in.
So I'm going to type a very specific command that says show interface and I want to see that port channel
number one.
All right.
There's a lot of garbage here.
But the important thing I want you to take a look at is right here.
You see where it says BW 200000 kilobits.
What that's telling us is that port channel right there is now running two 100 megabit connections together
so we have the total bandwidth of 200 megabits. So it's working, yay! Fantastic! And life is better. Now
there's a couple of things need to be careful with here.
If you remember we set the port up as active.
So you have a choice with LACP you can turn it on as active or as passive. When you set it up
as active
that means I don't care what's happening,
I'm sending out LACP traffic.
If you set up as passive,
that means I will wait till I hear from a port that is sending me stuff and then I'll start talking.
Cisco says set them all up as active. So you can do it the Cisco way, however, for the scope of the exam,
as long as you set one as active and one as passive It doesn't matter which one or both active it will
work.
If you set them as both passive it's not going to work.
So make sure you know that. The last thing I want to touch on is that when you've got these up and running
it's a very very bad idea to go into your configuration and take one of them out without first pulling
out your cable.
If you don't do that you're going to create a broadcast storm and there are lots and lots of famous
stories on the Internet of very large networks being taken down through one very very careful miscalculation.
So be careful.