IP Address• A Unique, 32-bit address used by computers to communicate over a computer network Types of IP Address Static Dynamic
Classful IP Addressing - I• IP address structure consists of two addresses, Network and Host• IP address is divided into five classes
Classful IP Addressing - II Byte 1 Byte 2 Byte 3 Byte 4Class A Network ID Host IDClass B Network ID Host IDClass C Network ID Host IDClass D Multicast AddressClass E Reserved for future use
Examples of Classful Addressing• 18.104.22.168 - The first byte of the address represents 14 which lies between 0 and 126, hence Class A address.• 22.214.171.124 - The first byte of address is 134 which lies between 128 and 191 hence the address belongs to Class B.• 126.96.36.199 - As first byte is 193 which is between 192 and 223, hence the address belongs to Class C.
Unicast, Multicast and Broadcast Addresses• Used to achieve communication on the Internet• Unicast address uniquely identifies a host in a network and belongs to class A, B and C• Multicast address defines an address for a group and belongs to class D• A system on a multicast network can have more than one class D multicast address• Broadcast address allows user to send data packet to all machines on a given network and is last address of that network
Guidelines for using an IP Address• All hosts located on same physical network segment must have same network address.• A unique host ID of the IP address must be allotted for each host on the network segment.• A network ID that starts with its first byte indicating 127 should not be used, as this value is reserved for loop back functions.• A network ID having all 1s in its host address field cannot be used, as this represents a broadcast address for the local network.• A network ID having all 0s in the network address field cannot be used for communication over Internet as this address represents the default network address.
IP Subnetting• Allows you to divide a network into smaller sub-networks• Each subnet has its own sub-network address• Subnet can be created within Class A, B, or C based networks
Subnet Mask• Specifies part of IP address used to identify a subnetwork.• Subnet mask when logically ANDed with IP address provides 32-bit network address Subnet Mask AND IP Address Operation Network Address
Default Mask• Has predetermined number of 1s• Class A, B and C contains 1s in network ID fields for default subnet mask Address Default Mask Class (in Binary) Class A 11111111.00000000.00000000.00000000 Class B 11111111.11111111.00000000.00000000 Class C 11111111.11111111.11111111.00000000
Classless IP Addressing• Ruled out fixed size network address• Network address can vary from 0-bit to 31-bit• Uses Classless Inter-Domain Routing (CIDR) addressing scheme• CIDR address notation: 188.8.131.52/18 First 18 bits represent network ID IP address
Variable Length Subnet Mask (VLSM)• Used by CIDR to allocate IP addresses to subnets depending up on the requirement• Allows network administrator to create variable size subnets within a network• Employs two different subnet masks at router which are ANDed one after another to the address
Example of VLSM - I• For example, if an organization is given a Class C address and the organization needs to have five subnets VLSM employs two subnet masks.• If the IP address is 184.108.40.206, consider the first subnet mask with 26 1s that is 255.255.255.192 or in binary format 1111111.11111111.11111111.11000000 which provides four subnets having 64 addresses in each subnet.
Example of VLSM - II• Further, one of the subnet having 64 host addresses is divided in two subnet having 32 hosts addresses by applying a mask of 27 1s that is 255.255.255.224 or 11111111.11111111.11111111.11100000 to one of the subnet from the four subnets. Refer to the figure in next slide.
Example of VLSM - III 220.127.116.11 – 18.104.22.168 22.214.171.124– 126.96.36.199 188.8.131.52 – 184.108.40.206 220.127.116.11 – 18.104.22.168 22.214.171.124 – 126.96.36.199
Special Addresses• IP addresses which are never used on the public Internet Types of Special Address Loop-back Link-Local Private Address Address Address
IPv6• Latest version of IP addressing over IPv4• Implements 128-bit network in contrast to 32-bit IP address used by IPv4• Address notation consists of 32 hexadecimal digits with every 4 digits separated by a colon
Ping, Tracert and Path Ping• Utility tools used for keeping track about hosts on the network and network structure• Ping (Packet Internet Groper) – Used by computer network to test whether intended host is reachable across IP network• Tracert – Used by Windows operating system to increase time-to-live (TTL) value of data packets sent• Pathping – Provides useful information about network errors, network latency and network loss at hops between source and destination address
Host Addressing In Mobile IP - I• Host cannot carry IP address from one network to another• IP address is valid only when the host is connected to a particular network• When a host moves from one network to another it requires IP addressing structure to be modified• To maintain network connectivity of host within new network: – Change IP address from one network to another – Use two IP addresses
Host Addressing In Mobile IP - II• To maintain network connectivity of host within new network: – Change IP address from one network to another - Provides network connectivity for mobile host when it travels from one network to another by changing IP address of mobile host – Use two IP addresses - Host uses home address when it is in permanent home network and uses care-of-address when it moves to foreign network
Agents in Mobile IP - I• Mobile IP includes two agents to make address Agents changes invisible to the rest of the Internet Home Foreign Agent Agent
Agents in Mobile IP - II• Home agent – Involves a routing device attached to home network of mobile host – Transmitting data packet from host to mobile host Packet Home Foreign Mobile Host Agent Agent Host Foreign agent Usually a router that is attached to foreign network Receives packet sent by home agent and delivers these packets to mobile host
Phases in Mobile IP• While communicating with a remote host, a mobile host has to undergo three phases
Inefficiency in Mobile IP• Mobile IP sometime may provide with inefficient communication which can be either severe or moderate.• Inefficiency may be caused due to: – Double Crossing – Triangle Routing