You will be familiar with IP because in order to address web pages, you must use domain names like www.barclayscapital.com, or their numerical counterparts called IP addresses.
| NOTE: Domain names are far easier to remember than IP addresses so we usually use domain names instead of IP addresses and rely upon Domain Name Servers to tie domain names to their IP address counterparts behind the scenes. |
IP addresses are unique sets of four period delimited octets that represent individual hosts on specific networks. A TCP/IP octet is a number between 0 and 255. Thus, an IP Address might look something like:
30.85.1.26
which you might read as something like "computer named 26, on network 1, on host 85, of network 30."
| NOTE: 255 is usually a reserved number which means broadcast to all hosts and 0 represents "this", or the current host. |
Besides defining the address scheme, IP also handles the transmission of data from an originating computer to the computer specified by the IP address. It does so by breaking up large, unwieldy chunks of data into easily manageable IP packets that it can deliver across the network.
That is why we talk of IP being a connectionless protocol. In an effort to better manage network traffic, IP specifies the protocol for breaking single messages into a slew of portions. Each portion is responsible for finding its way across the network based on changing traffic congestion and the IP protocol.
Each time a message arrives at an IP router, the router decides where to send it next. There is no concept of a session with a preselected path for all traffic. Routers can send data along the path of least resistance regardless of local network traffic congestion.
If one phone line on the network breaks down, for example, traffic can still reach its destination through a roundabout path.
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