3Com 3.01.01 Switch User Manual


 
4
NETWORK PROTOCOL OPERATION
This chapter covers the following topics:
Configuring IP Address
Configuring Address Resolution Protocol (ARP)
DHCP Relay
IP Performance
Configuring IP
Address
IP address is a 32-bit address represented by four octets. IP addresses are divided
into five classes, A, B, C, D and E. The octets are set according to the first few bits
of the first octet.
The rule for IP address classification is described as follows:
Class A addresses are identified with the first bit of the first octet being 0.
Class B addresses are identified with the first bits of the first octet being 10.
Class C addresses are identified with the first bits of the first octet being 110.
Class D addresses are identified with the first bits of the first octet being 1110.
Class E addresses are identified with the first bits of the first octet being 11110.
Addresses of Classes A, B and C are unicast addresses. The Class D addresses are
multicast addresses and Class E addresses are reserved for future uses.
At present, IP addresses are mostly Class A, Class B and Class C. IP addresses of
Classes A, B and C are composed of two parts, network ID and host ID. Their
network ID lengths are different.
Class A IP addresses use only the first octet to indicate the network ID.
Class B IP addresses use the first two octets to indicate the network ID.
Class C IP addresses use the first three octets to indicate the network ID.
At most, there are: 28 =128 Class A addresses, 216=16384 Class B addresses and
224=2,097,152 Class C addresses.
The IP address is in dotted decimal format. Each IP address contains 4 integers in
dotted decimal notation. Each integer corresponds to one byte,
e.g.,10.110.50.101.
Configuring an IP Address is described in the following sections:
Subnet and Mask
Configuring an IP Address