The following discussion describes the IP packet.
• Version indicates the version of IP currently used.
• IP Header Length (IHL)-Indicates the datagram header length in 32-bit words.
• Type-of-Service-Specifies how an upper layer protocol would be a current datagram to deal and knows datagrams various levels of interest.
• Total Length Specifies the length, in bytes, of the entire IP packet, including the dates and headline.
• Identification-Contains a number that identifies the current datagram. This field is used to help piece together datagram fragments.
• Flags-Consists of a 3-bit field of the two low-order (at least-significant) bits control fragmentation. The low-order bit determines whether the packet can be fragmented. The middle bit determines whether the packet is the last fragment in a series of fragmented packets. The third or high-order bit is not used.
• Fragment Offset indicates the position of the fragment's data in relation to the start of the data in the original datagram, which allows the destination IP process to properly reconstruct the original datagram.
• Time-to-Live-Maintains a counter that gradually decrements down to zero, at which point the datagram is discarded. This keeps packets from looping endlessly
. • Protocol-Indicates which upper-layer protocol receives incoming packets after IP processing is complete.
• Header Checksum help ensure IP header integrity.
• Source Address-Specifies the sending node.
• Destination Address-Specifies the receiving node.
