Original subtitles

What I'd like to point out once again is that each web site is resolved to a different IP address.

Lastly if I ping CNN.com notice that that also resolves to an IP address but it's different to the previous

examples.

DNS is doing the name resolution so it's resolving a domain name to an IP address and that's how I'm

learning the IP address of CNN dot com or Google dot com.

You can ping many of the well-known Web sites on the internet to find out what the IP addresses are.

You could also use this look up which just does a DNS resolution of a domain name rather than trying

to pin the server.

So in summary the devices on the Internet have been configured with IP version 4 addresses.

I'll explain more about the formatting of IP addresses in the next few minutes.

But for now just take note that every device has an IP address and that includes my own machine or the

command IP config will show me the IP address on my local machine.

When using Windows.

So in this example my IP version 4 address is 10.0 0.6.

You'll also notice here that I have an IP version 6 address of 2001 Colin 20 colon colon.

In this video we are concentrating on IP version for addresses but in another video I'll explain IP

version 6 IP version 6 is becoming more and more important because IP addresses are now exhausted in

certain parts of the world IP version 4 or Internet Protocol version 4 is a layer 3 or network a layer

protocol as per the OS model.

You know different video.

I explained the OS on model.

So if you're not sure about layers Please refer to that video IP version 4 is a connection list protocol.

In other words there are no sessions formed when traffic is transmitted.

The transmitter simply sends data without notification to the receiver.

No status information is sent back from the receiver to the transmitter.

It's totally connection less TZP for transmission control protocol.

On the other hand is connection orientated TZP will set up a session.

So before transmission takes place in TZP the transmitter sends what's called a sun or synchronization

message to the receiver.

There's a sim ack message from the receiver to the transmitter and then a ack or acknowledgement message

from the transmitted to the receiver.

So before any data is transmitted but devices using TZP go through what's called the three way handshake.

Some send ack and ack IP on the other hand doesn't do any of that.

Each packet is treated independently of other packets.

That's why traffic can take different paths to get to a destination.

Rodders will route the traffic via different paths based on options such as load balancing because each

packet is independent.

An IP is a connection list protocol.

Routers can also base routing decisions on different values such as bandwidth or hop count.

But it is possible that packets from one session take divergent or different parts to get to a destination.

So for example Ripp will base its routing decisions on hop count which is not good and hence Repp is

not used that often anymore.

OSPF will base it on bandwidths other running protocols will use their own metrics to determine the

best path.

I'll be discussing routing protocols in more detail later in this course but in brief writing protocols

determine the best path or best route from A to B.

This is based on the whole Rockhill addressing structure in IP version for an IP version 6 where we

have both a network and host portion as part of the address Rawdon's base their routing decisions on

the network portion of the address rather than on the host portion of the address and I'll explain network

and host portions in a moment.

IP also only gives best effort to delivery of packets.

There is no guarantee of packet delivery any packet could be misdirected.

It could be duplicated or it could be lost in transmission when sent to a destination and that should

be expected in IP transmissions.

Once again TZP which is a connection oriented protocol has the ability to read transmit packets that

go missing UDP another layer for protocol doesn't retransmit packets.

If they get dropped simply lost and the applications need to take care of that.

There is also no data recovery features in IP.

If the packet for example gets corrupted the end devices need to handle that and not the routers in

between.

So in summary IP has no boltin sessions no data recovery no retransmissions Hialeah protocols such as

TCAP will need to handle dropped packets corrupted packets misdirected packets and so forth.

IP does not provide those features and relies on Hialeah protocols to implement those features.

So let's look at the format of an IP version for address an IP version for address is 32 bits in size

normally written in dotted decimal notation such as this example 10 dot one dot 1.1 each of value such

as 10 is 8 bits in size.

So in other words we have x x x done X with each X being 8 bits in length.

Also known as an octet the total size of the address is 32 bits.

Please refer to the binary video.

If you're not sure about bits and how to convert this address into binary and back again IP addresses

once again have a rock hill structure to enable routing which consists of two main parts.

We have the network portion of an address and the host portion and we look at that in more detail in

a moment.

IP addresses are used for routing in a very similar way to the way DHL or FedEx ranked parcels based

on a destination address route as will route traffic to a destination address.

When unicast packets are transmitted multi-course packets use a different mechanism and do a routing

based on source address.

So as an analogy DHL or FedEx are sending the possible to a destination based on the destination on

the parcel routers are sending packets to destinations based on the destination address in the packet.