IP Addressing

IP Addresses (cont.) IP addressing allows for seamless integration amongst heterogeneous networks. To send a packet, the destination address is the IP address of the computer, not the hardware address! This allows for communication across networks.

IP Addresses (cont.) 32 bits in length (IPv4) 128 bits in length (IPv6) Addresses are divided into a prefix and suffix The prefix is the network_Id The suffix is the host_Id

Class First OctetSubnet maskNo. of N/WsNo. Of Hosts A B C PS :0,10,110 are called N/W_Identifiers for Class A, Class B & Class C respectively.

Dotted Decimal IP addresses are generally read in dotted decimal format through Much better than reading:

IP Classes People commonly throw around terms like “Class C”, but it should really be termed “Class C address” or “Class C address space.” Class A: hosts! Class B: Class C: 256

IP Class Scheme From the previous figure, we see that the 32-bit address is split into 4 octets. IP addresses are self identifying. If the first 4 bits of the first octet are – 0xxx: Class A address – 10xx: Class B address – 110x: Class C address – 1110: Class D address (Multicast) – 1111: Class E address

Dotted Decimal with Classes Class A: – 1 prefix octet (128 networks) – 3 suffix octets ( hosts) Class B: – 2 prefix octets (16384 networks) – 2 suffix octets (65536 hosts) Class C: – 3 prefix octets ( networks) – 1 suffix octet (256 hosts)

Address Space

Special Addresses (cont.) Limited Broadcast Address – All 1’s in the entire address. – Limited broadcast address is restricted to the local subnet. –

Special Addresses (cont.) Loopback addresses – Loopbacks are used for testing. An IP looback is application-level testing. – Any information sent to the loopback address is never passed to the network segment. It is handled internally in the TCP/IP stack. – 127.x.x.x

Special Addresses (cont.) This computer’s address – If a computer doesn’t know what it’s own address is, but needs to communicate to another machine, it designates the address of for itself. – Applications include DHCP,BOOTP. BOOTP provides N/W configuration information to diskless workstation if necessary on the LAN.