Compaq 222863-001 - TaskSmart W2200 Model 10 Administration Manual page 112

B-8 Compaq TaskSmart W2200 Appliance Server Administration Guide
Classless Inter-Domain Routing (CIDR) subnets use variable length subnet
masks and are not restricted to 8-bit class boundaries. Subnets may exist with a
subnet mask where the low order bits (right side of the range) consist of
contiguous zeros and the high order bits (left side of the range) consist of
contiguous ones. CIDR subnets are represented by a suffix that designates
/xx
the number of ones in the mask.
For example: 192.168.1.0/22 represents a subnet with a 22-bit subnet mask
that allows up to 2,047 hosts.
An address can be set in two ways. One is a static address, and the second is a
dynamic address. A static address is manually assigned to a specific device.
The IP address cannot change until it is again manually changed. Dynamic IP
addressing allows that each device requests an address, and then that device
uses that address on a temporary basis.
Dynamic Host Configuration Protocol (DHCP) is a protocol that assigns IP
addresses to devices as they request one. Usually a request for an address is
made when a device is booted. The address is returned to the address pool
when the device is shut down or the lease on the address expires and is not
renewed. This method of handling addresses is a convenient method for the
administrator because he or she does not have to physically reset all the IP
addresses every time somebody needs one.
A final point to make regarding addressing involves names versus addresses.
A Domain Name System (DNS) is a system that enables a correlation between
IP addresses and a domain name. The system was devised to help users
navigate the Internet without needing to remember the specific IP address of
websites that they want to visit or access. For example, an administrator wants
to access the Compaq main website. The IP address for the website is
161.114.1.225. If not for the DNS, the administrator would have to retype the
IP address for that website every time he or she wanted to visit that website.
The user only needs to type in and a DNS associates the name Compaq
Compaq
with the address 161.114.1.225. This convention not only saves time, but also
money.