Time
31 hours 29 minutes
Difficulty
Beginner
CEU/CPE
30

Video Description

Routers This lesson discusses routers which allow us to move data across different networks. Routers are able to segment and subnet as well as manage traffic flow. Routers also manage tables. This means in order for a router to know where to go next, it must have a table to send data too and allows for data to be sent outside of the network. Routing tables are either static or dynamic.

Video Transcription

00:04
what? Our routers. What routers? D'oh!
00:07
Well, if
00:08
all of our other devices allowed us to move data across our same network allowed us to move data across our internal network. Routers
00:17
are what allow us to move data across two different networks. Allow us to take I p address packets and move them to networks that have you a different i p address network, or use different protocols or use a different apology.
00:31
So that's what our routers do. They move the data data across different networks.
00:36
They allow us to also perform things such as segmentation and sub netting. They allow us to take our network, which is in our same local area and sub net out, or segment that out that network and still allow us to communicate between those networks and our office by taking those data and moving it to those different networks.
00:55
This segmentation may be necessary for trying to help clean up some of our network traffic,
00:59
help clean up some of our broadcast domains
01:03
which wants to talk about later. Our routers also help manage traffic flow. They help manage where specific data goes next. They helped to speed up connective ity by maintaining routing tables and maintaining where data needs to go next in order to get to its final destination.
01:19
So that's what all routers D'oh. Moving data across the different networks
01:25
now. Routers, managed tables. Now what does that mean? They writers aren't waiters. So what? What do you mean by they manage tables? Well,
01:34
in order for a router to know where to go to next, it has to have some sort of table that tells it where it sends data, too.
01:44
If we just send a packet to our router that says I want to go to google dot com.
01:49
Well, how does our router know where the heck that is? How does our router know where the heck it needs to go to ask what a google dot com is? Needs to know where to go to get If we don't have local D. N s. With google dot com cashed. We need to know. Okay, well,
02:06
where do I go in order to get to this D N s server? They're referring in order to bring them back a response
02:12
so that then I can go out again and find out how to get to google dot com How do our Internet service providers routers know how to get to all of these different Internet addresses? Well,
02:23
I can tell you now that the little rodders we have inside our house don't have all the network paths told a different I p addresses in the world.
02:30
They'd be much bigger than just our little tiny routers.
02:34
Um,
02:35
our routers managed tables which let them know mostly the next. The closest networks that we have the networks that we may have in our environment and our enterprise and also let them know of where to go and where to send data. If it's not sure
02:53
if it doesn't have a routing table entry for this.
02:55
So router tables let our router know where to send data to outside of its own little network.
03:04
So if we do have a network that consists of multiple routers across our domain, if we have a big enterprise network with multiple users on multiple different I p address I p address sub nets connected to multiple routers across our enterprise, those routers rounding tables
03:20
will know the best ways to get to the other networks and the fastest ways to transmit data.
03:27
That's the other part of routing tables. Routing tables also help us to manage not only where to sin dated to in order to get there, but also hopefully includes the best way to get there.
03:40
If we're trying to send data or we're trying to send a file to a file server, that's on a different network in our enterprise.
03:46
It be best if I router knows the fastest way to get there. So we don't have to go alone around the world in order to get to our server.
03:54
Um, it's best if weaken if our rather simply says Okay, I know that if I send the if I send this packet this way, it's gonna tweet. Take it twice is long to get there and get a response. And then if I send it around this way, so it's best to know it's best that our routers keep a managed table of that.
04:14
Now. Our routing tables are either static or dynamic.
04:18
It's either one or the other, and the reason being dynamic means they're automatic. They automatically update they automatically change themselves, and static is manual mode static, just like our static I P. addresses mean that we need to go in and we need to manage those tables, and we need to add interest to those tables
04:38
and manage the different paths.
04:40
Um,
04:41
both have their pros and cons with static. We would have to be constantly updating and managing those tables. And if something were to go down or something were to break, then are and we didn't have some fall back set. We didn't have a secondary. We didn't have a secondary path set than a router. Wouldn't know how to get somewhere else because it wouldn't be dynamically updating,
05:00
whereas dynamic it may. Our router may pick a path which may not be the best path or may not be the way that we wanted to go. So there may be some hybrid going on there. There may be may have ah router set to dynamically create new paths and dynamically update its tables.
05:18
Except for this static path we have set where if somebody is trying to get to this network, they need to go along
05:24
this path. So if we're noticing that we have network set up in our network were noticing that we have network set up
05:30
and our enterprise, where we have routers on them. And whenever I'm trying to send a packet here whenever I'm trying to send data here, my computer, my router isn't really sending me to the right place or sending me this long, roundabout way. Or if, for one reason or another, it wouldn't be able to dynamically find this path.
05:48
I need to go in and I need to statically set this path,
05:51
and it's a statically put in the information that my router requires in its routing table in order to get from Point A to this network that it knows about
06:00
now
06:02
when we're using a dynamic when we're using dynamic routing tables are routers use different protocols in order to find out the best way to get to where they need to go
06:12
now. These include things such as Open Shorter's Open, Shortest Path, first Border Gateway Protocols, E G. R P R I. P R P. Version, too. It's a lot of different protocols, and it's a lot of different calculations and a lot of different components of a connection
06:31
that are involved with our router. Determining the best path to get somewhere
06:36
I think about it this way.
06:41
You may know of a couple different ways to get the work.
06:45
You may know of some side streets and some back roads, and you may know the highway
06:50
well. Sometimes you may take different ways to get toe work, depending on the time of day in the day of the week. Why's that? Why don't you just take the highway every single day? That's the most directed. That that's the most direct way. And it's the largest road, just like with our with our routing table. With our routing path, we may have
07:11
a link connection that it allows for the greatest amount of bandwidth, and it's the most direct path to where we need to go.
07:17
So why wouldn't we choose that every time? Well, maybe during
07:21
certain peak hours or certain times of the day. That road has a lot of traffic on it, and it's gonna take us a long time to get there and to get a packet back. But if we go down the side streets if we go down this other route while in theory and initially may seem less appealing because it takes is a couple more hops to get there and
07:41
the band with us a little bit less.
07:43
We may still get there faster and may be able to perform our operations faster because that other path doesn't have as much.
07:50
It doesn't have as much traffic on it.
07:53
Conversely, we may have.
07:56
We may have side roads that would get us tow work more directly than going down another road, which goes a long roundabout way. But the side roads that go to work directly may have a dozen red lights in them.
08:11
May have a lot of may, may have or may have. A very short, short and narrow road may have a very low speed limit,
08:18
so we have this very direct, very straight toe work road. We have a very direct path that are router takes very little hops to get there, maybe two or three hops to get to where it needs to go. But
08:31
it's a very narrow bandwidth road. It's a very low speed limit,
08:35
whereas we have another way around. That may take a couple more hops, but we have ah, higher bandwidth. We have a higher speed limit to get there. So all of these different calculations all of these different the different ways that our routers get. The different locations are included in
08:52
these different protocols, which take all of these different considerations into effect.
08:58
Some of them do. Some of them don't which take different considerations into effect for our routers to determine the best way to get to places and assign values as the best ways to get the places. But we'll talk about each of those individual protocols a little bit later.
09:11
No,
09:13
our routers are what we're going to typically to set as our default gateway. Why's this? Well, our routers will only address direct packets
09:22
if we're trying to send. If we're trying to get a packet somewhere and we're saying Okay, I want to send a packet to this I P address That's not on my network.
09:31
And we just send that out to everybody and we say, Hey, everybody, I'm trying to get to this server. Can you soon this packet. Can you forward this packet onto this server?
09:39
Our router won't address that. If it's a broadcast packet and sent to everybody, our routers don't Ford. Broadcast packets are routers will only forward packets that air directly addressed to them
09:52
now our computer,
09:54
our default will only send packets that it doesn't know where else to send them. It sends them to our default gateway.
10:01
So
10:03
if we don't know where to send the packet in, our computer says,
10:07
Hey, I need to send this packet here, but I don't really know where that is. I'm not going to send out a broadcast to everybody and ask everybody to pass this along. I'm going to send a direct packet to mind default Gateway who is then going to pass this along.
10:24
So that's why we set our router as our default gateway because a our routers on Lee address packets that are on Lee that are specifically addressed to them. Our routers will only address, and there will only pass on direct packets and be our routers will. Only our computers will send
10:43
to their default gateway packets that they don't know where else to send.
10:50
So that's why that's our router reason. So this is on the router side. Our routers will only address the direct packets and are on our computer side. Our computers sinned packets. They don't know where else to send them to back. Instead on different networks to their default gateway. So that's why we set our routers or default gateway,
11:09
and that's what our default gateway means. It's
11:11
where we send packets. We don't know where else to send them.

Up Next

CompTIA Network+

This CompTIA Network+ certification training provides you with the knowledge to begin a career in network administration. This online course teaches the skills needed to create, configure, manage, and troubleshoot wireless and wired networks.

Instructed By

Instructor Profile Image
Anthony Harris
Systems Analyst and Administrator at SAIC
Instructor