Operation Manual – IP Addressing and PerformanceH3C S7500E Series Ethernet Switches Chapter 1 IP Addressing Configuration1-2Table 1-1 describes the address ranges of these five classes. Currently, the first threeclasses of IP addresses are used in quantity.Table 1-1 IP address classes and rangesClass Address range DescriptionA 0.0.0.0 to 127.255.255.255The IP address 0.0.0.0 is used by ahost at bootstrap for temporarycommunication. This address isnever a valid destination address.Addresses starting with 127 arereserved for loopback test. Packetsdestined to these addresses areprocessed locally as input packetsrather than sent to the link.B 128.0.0.0 to 191.255.255.255 ––C 192.0.0.0 to 223.255.255.255 ––D 224.0.0.0 to 239.255.255.255 Multicast address.E 240.0.0.0 to 255.255.255.255 Reserved for future use except for thebroadcast address 255.255.255.255.1.1.2 Special Case IP AddressesThe following IP addresses are for special use, and they cannot be used as host IPaddresses:z IP address with an all-zero net ID: Identifies a host on the local network. Forexample, IP address 0.0.0.16 indicates the host with a host ID of 16 on the localnetwork.z IP address with an all-zero host ID: Identifies a network.z IP address with an all-one host ID: Identifies a directed broadcast address. Forexample, a packet with the destination address of 192.168.1.255 will bebroadcasted to all the hosts on the network 192.168.1.0.1.1.3 Subnetting and MaskingSubnetting was developed to address the risk of IP address exhaustion resulting fromfast expansion of the Internet. The idea is to break a network down into smallernetworks called subnets by using some bits of the host-id to create a subnet-id. Toidentify the boundary between the host-id and the combination of net-id and subnet-id,masking is used. (When subnetting is not adopted, a mask identifies the boundarybetween the host-id and the host-id.)Each subnet mask comprises 32 bits related to the corresponding bits in an IP address.In a subnet mask, the part containing consecutive ones identifies the combination of
