IP Addresses

An IP address is made up of 32 bits of information. These bits are divided into four sections, referred to as octets or bytes, each containing one byte (eight bits). In the IP address 172.16.30.100, for example, 172.16 is the network address.

This number can also be referred to as a host address. In the sample IP address 172.16.30.100, 30.100 is the node address. The network address of an IP address can differ based on the subnet mask used. In the example here, we used a 24-bit subnet mask, which equals 255.255.255.0.

In a Class A IP address, only the first octet identifies the network. This means that the address would be viewed as network.node.node.node. How do you know if it is a Class A address? The network address will always be from 1 to 126. Technically, the 127 network is also a Class A network, but the network is reserved for diagnostics and the address of 127.0.0.1 is reserved for loop backing on the local interface. The 10 network (along with the 127 network) is not valid on the Internet it is used for internal addressing.

Class B IP addresses are a little trickier. If the first octet has a value between 128 and 191, the address is a Class B network. The second octet is still part of the network address but can be any value under 255. So the IP address would be viewed as network.network.node.node. The 172.16 network is a Class B network that is not valid on the Internet it is used for internal addressing.

Class C IP addresses are just about as tricky as the Class B. The first three octets identify the network, leaving only 254 available hosts in each network. Class C networks always start with a value of 192 to 223 and would be viewed as network.network.network.node. The 192.168.10 network is reserved for internal network addressing yet another network not valid for use on the Internet.

Note : Remember that values in an octet can never be lower than 0 or higher than 255. A 255 in the node address portion of the last octet always indicates that the address is a broadcast address.

IPX Addresses

An internetwork Packet Exchange (IPX) address is 80 bits, or 10 bytes, long, which is significantly longer than an IP address. As with TCP/IP addresses, IPX addresses are hierarchical and divided into network and node portions. The first four bytes always represent the network address, and the last six bytes always represent the node address.

The actual node address is always the MAC address assigned to the NIC on the machine using the IPX protocol. A MAC address is always 12 hex digits; for example, AB23.45FF.3428. The network portion of the address can be up to eight hex digits long; for example, A6B32398. Put the network address and
the node address together, and it looks like this: A6B32398. AB23.45FF.3428. They can be deceiving too. If you have a small network address such as the network 00002374, then the IPX address can look like this: 2374. AB23.45FF.3428.

Related posts:

1. Network Addressing Exams Points
2. Data link and Network Addresses
3. Classes of IP addresses and subnetting
4. MAC Addresses Exams Point
5. Verify IP addresses Lab
6. Layered Model Exam Points
7. Data link and Network Addresses Exams Points
8. Function of the MAC Address
9. Full and Half-Duplex Ethernet Operation
10. LAN segmentation using bridges and switches