February 14, 2020
Amitraj
Internet Protocol Version 4
-> IPv4 short for Internet Protocol Version 4 is the fourth version of the Internet Protocol (IP).
-> IP is responsible to deliver data packets from the source host to the destination host.
-> This delivery is solely based on the IP Addresses in the packet headers.
-> IPv4 is the first major version of IP.
-> IPv4 is a connectionless protocol for use on packet-switched networks.
-> IPv4 is defined and specified in IETF publication RFC 791.
IPv4 Header-
The following diagram represents the IPv4 header-
VERSION: Version of the IP protocol (4 bits), which is 4 for IPv4
Header length: IP header length (4 bits), which is the number of 32 bit words in the header. The minimum value for this field is 5 and the maximum is 15.
Type of service: Low Delay, High Throughput, Reliability (8 bits)
Total Length: Length of header + Data (16 bits), which has a minimum value 20 bytes and the maximum is 65,535 bytes.
Identification: Unique Packet Id for identifying the group of fragments of a single IP datagram (16 bits)
Flags: 3 flags of 1 bit each : reserved bit (must be zero), do not fragment flag, more fragments flag (same order)
Fragment Offset: Represents the number of Data Bytes ahead of the particular fragment in the particular Datagram. Specified in terms of number of 8 bytes, which has the maximum value of 65,528 bytes.
Time to live: Datagram’s lifetime (8 bits), It prevents the datagram to loop through the network by restricting the number of Hops taken by a Packet before delivering to the Destination.
Protocol: Name of the protocol to which the data is to be passed (8 bits)
Header Checksum: 16 bits header checksum for checking errors in the datagram header
Source IP address: 32 bits IP address of the sender
Destination IP address: 32 bits IP address of the receiver
Option: Optional information such as source route, record route. Used by the Network administrator to check whether a path is working or not.
-> Due to the presence of options, the size of the datagram header can be of variable length (20 bytes to 60 bytes).
-> IPv4 short for Internet Protocol Version 4 is the fourth version of the Internet Protocol (IP).
-> IP is responsible to deliver data packets from the source host to the destination host.
-> This delivery is solely based on the IP Addresses in the packet headers.
-> IPv4 is the first major version of IP.
-> IPv4 is a connectionless protocol for use on packet-switched networks.
-> IPv4 is defined and specified in IETF publication RFC 791.
IPv4 Header-
The following diagram represents the IPv4 header-
VERSION: Version of the IP protocol (4 bits), which is 4 for IPv4
Header length: IP header length (4 bits), which is the number of 32 bit words in the header. The minimum value for this field is 5 and the maximum is 15.
Type of service: Low Delay, High Throughput, Reliability (8 bits)
Total Length: Length of header + Data (16 bits), which has a minimum value 20 bytes and the maximum is 65,535 bytes.
Identification: Unique Packet Id for identifying the group of fragments of a single IP datagram (16 bits)
Flags: 3 flags of 1 bit each : reserved bit (must be zero), do not fragment flag, more fragments flag (same order)
Fragment Offset: Represents the number of Data Bytes ahead of the particular fragment in the particular Datagram. Specified in terms of number of 8 bytes, which has the maximum value of 65,528 bytes.
Time to live: Datagram’s lifetime (8 bits), It prevents the datagram to loop through the network by restricting the number of Hops taken by a Packet before delivering to the Destination.
Protocol: Name of the protocol to which the data is to be passed (8 bits)
Header Checksum: 16 bits header checksum for checking errors in the datagram header
Source IP address: 32 bits IP address of the sender
Destination IP address: 32 bits IP address of the receiver
Option: Optional information such as source route, record route. Used by the Network administrator to check whether a path is working or not.
-> Due to the presence of options, the size of the datagram header can be of variable length (20 bytes to 60 bytes).
