In a more basic world it's fairly easy to separate routers from switches. Routers are going to filter and
forward traffic based on Layer 3 of the OSI seven layer model IP addresses and switches use Layer
two MAC addresses.
Well the problem we're starting to run into especially you've been keeping up on an episode of episode
bases is that we're beginning to discover that the whole idea between what switches can do and what
routers can do begins to be a little bit fuzzy.
So one of the things that we need to begin to appreciate is that we have to be able to go in and configure
switches.
Now the challenge here is that if you've been watching previous episodes you can appreciate that for
the most part.
Somehow you know a magic IP address and you plug in you type that IP address into your web browser and
you get some kind of magic configuration screen.
And generally that's true.
However for the network
plus we need to look at some other alternatives and probably the best place to start would be with this
old Cisco switch right here.
Now if you take a look at the front of the Cisco switch it's not too terribly exciting.
We've got 24 ethernet ports.
However if you take a look at the back
I want you to see that right there.
This is a console port. Console ports allow you to access, really not just switches you can do this
with Cisco routers, you can access these devices without even knowing an IP address or anything else
like that.
Now in order to make this happen you need to have one of these very famous rollover cables and this
cable plugs into the console port. Let me show you the shape of the ends.
So I've got a regular old school DB9 serial here on the left and on the right,
at first glance you'd look at that and go Oh that's an RJ 45.
Well it does look like an RJ 45 but it's got a very unique proprietary wiring so it's not an Ethernet.
It is nothing more,
it's really a serial connection.
So what I want to do is let's go ahead and get this up and running. Now to make this work
you plug one end into your console port and then you plug this and into your serial port.
Well guess what.
I don't have a serial port on my laptop but I've got one of these handy dandy adapters.
Now the downside to running things this way is that.
And you'll use something like putty, fire putty up and you'll get the connection.
The downside to running things this way is that the serial connection is incredibly slow. It's runs at
9600 baud.
So it's really slow.
So what I'm going to do here is I'm going to cheat a little bit.
I'm going to go ahead and connect via, you ready, Ethernet.
Most of the switches have some features that allow you to connect in using telnet over your ethernet
connection.
So I'm going to use putty and I'm going to use actually use telnet so I'm going to cheat a little bit.
The nice part is is the interface is absolutely identical to the one you'd see by running through the
rollover port.
But it'll be fast enough that we won't fall asleep during the presentation.
So give me a second.
I'm going to plug this in and let's take a look at the most raw type of interface you can see.
And actually it has an operating system called IOS.
Let's take a look.
OK so here I am I've got putty up and running.
Now one of the things I love about putty is that you can use it for just about any connection. If I wanted
to use my rollover I can just go ahead and set it to serial.
I would set the COM port on my particular system's Com 3 and I set the baud rate to 9600, which
is the default for Cisco stuff.
And if I had it plugged in we would just hit open and off we'd go.
But I'm going to cheat and I'm going to use telnet.
I typed in the IP address for my device and I just hit open.
Let me type in a password, ta-da, you are in Cisco's IOS interface.
IOS is a very very powerful operating system that pretty much all Cisco switches and routers run on.
Now
I don't want to turn this into an IOS course but there are a few commands.
For example I want to go into a enable mode which is really where all the fun begins and you can see
that I have the name of the switch plus the pound sign which tells me I'm in the Enable mode and I can
do all kinds of stuff like show. So what I just did there is I said show me the startup file for my particular
system and I can go through and see everything what is currently set for the startup.
Right now there's not much in there because it's pretty much almost exclusively set up from the factory.
But it's all there.
So there's clearly more than just plugging in and getting to a web browser to figure out how to configure
something.
So we've used a rollover cable.
We actually even used telnet which you can do for a lot of devices.
Now what I want to do is go back to the idea of running using a web interface. Now to do that,
what I'm going to do is I'm going to unplug and I want to plug into this Netgear.
So I'm just going to plug it in to any connection I want.
It doesn't really matter too much which one I use.
And the reason I like this Netgear box so much is because it has a lot of extra features that you'll
see in switches. Certainly it has VLAN.
But there's a few other things in there that we're going to see with advanced types of switches that
is really kind of handy. So let's jump back in one more time.
I'm going to fire up my web browser.
And let me connect to this little switch and we can just poke around. Just a couple of more things I'd like
to show you.
All right now what I want to do here is just get into this little switch.
Now remember this is not a router it's just a switch.
OK.
So everything we're looking at is going to be a very switchy type thing.
So first of all we're fired up and we'll see that
here's his IP address.
This is the factory default and there, somewhere in there, we can make some changes. So let's take a
look. So we can do just the basic setup if we want to give it a name if we want to give it an IP address.
You can see right now
it's designed to get IP addresses from a DHCP server.
But if I wanted to and this is something that's really common I don't want to have to guess what my
switches IP address is so I can assign it to an IP address that is part of my network and I could go
ahead and give a subnet mask and gateways all, but I could give it this and then I'll document that, so
it will always have this anytime I need to configure my switch.
I go to any web browser and type that in and life's good.
So let's take a look at some of the other things we have in here.
We can actually set up access list to.
We can set up a very basic access control list to determine who we can get in here that type of thing.
We have port configuration. In terms of port configuration on switches there's usually not a ton you
can do.
But for example we can force a speed and also force what's known as flow control.
There's not a good reason to do that that I'm aware of.
Another one I will show you here is quality of service. QOS is actually a pretty interesting tool and
we can set up priorities for different types of traffic and these priorities go from zero to seven
on this particular router, and we can apply this type of priorities to say I don't know FTP traffic
and we can actually throttle a percentage of our total bandwidth for things like that.
Here's VLAN and it's got a very simplistic VLAN compared to if you've been watching in earlier episodes
the kind of cool stuff that we'd see with Cisco.
But I set up a VLAN too, I just called it wireless and I set aside a few ports for it.
Now monitoring is actually kind of interesting because when we talk about monitoring keep in mind that
by definition a switch does not allow traffic to go out on all of the different ports.
So what we do instead is we can actually do something called port mirroring.
But in this case it's just called a sniffer port, so I'm going to turn it on and I'm going to say the
sniffer mode is I want to see everything is being sent and received and I can set a particular port.
In this case I'm going to say port number one is going to be the port
you listen in on and then I can sit here and say anything happening on any of these ports.
I want you to mirror it to this guy. So this is a great way to use monitoring tools and that type of
thing.
Now here's some advanced things that are kind of interesting.
First of all there's spanning tree protocol which is pretty common on better switches today and you
can either enable it or disable it. Mine's disabled for right now.
And that's because I don't have a risk of creating bridge loops by wiring my switches wrong so I keep
it turned off in general.
Now here's something called SNMP. SNMP or simple network management protocol is a tool that's
used by all kinds of devices but it's primarily used on switches and routers to have an idea of their
status so you can query them and things like this.
And what we're doing here is we're just setting up an IP address.
And then what you can do for this particular device. So I can set an IP address of.
So I'll set this address up and then you can create a community.
A community is just a name and all of the devices that share this common name will be members of a
community.
And then you can say whether they're Read-Only or read-write and then what they can actually do with it.
SNMP for the most part is really just used for monitoring routers and switches and things like that
from a single source.
Just to make a quick mention of it IGMP and what that's used for is that if you're actually going to
be doing multicast traffic you want to make sure this is turned on.
So if you've got somebody who's doing multicast you know video conferencing or things like that, those
are things that you want to have turned on.
Next one is what we call Port rate setting where you can actually set how fast either as a percentage
of the total bandwidth or in a raw value as you see right here how fast you can set a port.
So for example I can actually slow certain ports down in case there is a problem with them or I don't
want somebody to eat up all my bandwidth.
Now all I'm trying to do with this episode is give you an idea of some of the things that you might
be able to see within a more powerful managed switch.
So keep in mind that even though it's not a router, it's not doing any of the hairier stuff that you're
probably used to seeing.
These little boxes can carry a lot of weight and do a lot of important features for you.
So don't be afraid to go into your managed switch poke around a little bit.
Oh and for crying out loud.
Change the default password
or I'm going to hack it myself.