HP VCX Software manual IP address, Mask/Bits

Chapter 3. Configuring 3Com VCX IP Telecommuting Module

You can perform all of these functions on the Save/Load Configuration page under Ad- ministration.

Configuring IP addresses and masks in 3Com VCX IP Telecommuting Module

IP address

IP addresses are written as four groups of numbers with dots between them. The numbers must be between 0 and 255 (inclusive); for example, 192.168.129.17.

Mask/Bits

The binary system uses the numbers 0 and 1 to represent numbers. A binary digit is called a bit. Eight bits in the binary system can represent numbers from 0 to 255.

The mask indicates how much of the IP address is used for the network address and the computers’ individual addresses, respectively. A mask consists of 8+8+8+8 = 32 bits. Below is a mask with 26 bits set to 1, which means that 26 bits of the IP address is locked to the network address and can’t be changed within the network.

Bits	11111111	11111111	11111111	11000000
No.	255	255	255	192

In the 3Com VCX IP Telecommuting Module, a mask is written either as the number of bits that are 1 or as four numbers (0-255) with dots between the numbers.

Sometimes it can be convenient to give a group of computers a network name, such as Administration, or specify that only a handful of computers can change the Telecommuting Module configuration.

You can form a group of computers with a network name, if the computers have consecutive IP addresses. In order to do this, you must set the mask to indicate that the network group consists of those computers only. The lowest IP address for these computers tells the network number of the group.

This is easiest to explain with a simple example. You have 7 computers that will make up a group called Administration.

Take the nearest power of two above the number of computers you want to include: 2, 4, 8, 16, 32, 64, 128 or 256. Since you have 7 computers, 8 is the nearest. In this example, one IP address is free for future use.

Give the computers consecutive IP addresses. Make the first IP address a multiple of the

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