Core Networking

Core Networking

Why Not Reserved IPs on Internet (STRUCTURE of an IP ADDRESS)

Every station on a PSN (packet switched network) that is based on the TCP/IP protocol (your computer is one, for example. Yes, we're referring to a host that is connected to the net) must have an IP address, so it can be identified, and information can be relayed and routed to it in an orderly fashion.

An IP address consists of a 32 bit logical address. The address is divided
into two fields:

1) The network address:
Assigned by InterNIC (Internet Network Information Center).
In fact most ISPs (internet service providers) purchase a number of addresses
and assign them individually.

2) The host address:
An address that identifies the single nodes throughout the network. It can be assigned
by the network manager, by using protocols for it such as DHCP, or the workstation itself.

[The IP networking protocol is a logically routed protocol, meaning that address 192.43.54.2
will be on the same physical wire as address 192.43.54.3 (of course this is not always true. It depends on the subnet mask of the network, but all of that can fill a text of its own)

IP address structure:


---.---.---.---

^ ^
| |
network | host

Every " --- " = 8 bits.
The first bits ===> network address
The last bits ===> host address.
with 8 bits you can present from 0-255 . (binary=(2 to the power of 8)-1)

Example:
11000010.01011010.00011111.01001010 (binary)
194.90.31.74 (decimal)

Notice the address range 127.X.X.X.
These addresses are assigned to internal use to the network device, and are
used as an application tool only. For example: 127.0.0.1, the most common one,
is called the loopback address - everything sent here goes directly back to
you, without even traveling out on the wire.
Also, some IPs are reserved for VPNs - Virtual Private Networks. These are
local area networks over wide area networks that use the Internet Protocol to communicate, and each computer inside the network is assigned with an IP address. So, suppose a certain computer wants to send a data packet to
another host on the network with the IP 'x', but there's also another host on
the Internet that has the same IP - what happens now?

So this is why we cannot use these and other forms of reserved IPs on the Internet.


1 comments:

Anonymous said...

great !!!!

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