- Internet Protocol
- Abbreviated IP, IP version 4, and IPv4. The session-layer protocol that regulates packet forwarding by tracking addresses, routing outgoing messages, and recognizing incoming messages in TCP/IP networks and the Internet.The IP packet header contains the following fields:• VersionVersion number of the protocol.• IHL (Internet header length)Length of the header information. The header length can vary; the default header is five 32-bit words, and a sixth word is optional.• TOS (Type of Service)Various levels or types of service.• Total lengthLength of the datagram in bytes, which can be a minimum of 576 bytes to a maximum of 65,535 bytes.• IdentificationInformation that the receiving system can use to reassemble fragmented datagrams.• FlagsThe first flag bit (DF) specifies that the datagram should not be fragmented and must therefore travel over networks that can handle the size without fragmenting it. The second flag bit (MF) indicates whether this is the last fragment.• Fragment OffsetAn indication of where this datagram belongs in the set of fragments; is used during reassembly.• Time-to-Live (TTL)Originally, the time in seconds that the datagram could be in transit; if this time was exceeded, the datagram was considered lost. Now interpreted as a hop count and usually set to the default value 32 (for 32 hops), this value is decremented by each router through which the packet passes. Once it reaches zero, the datagram is discarded.• ProtocolIdentifies the transport-layer process intended to receive the datagram.A value of 6 indicates Transmission Control Protocol (TCP), and a value of 17 indicates User Datagram Protocol (UDP).• Header checksumChecksum for the header.• Source addressIP address of the sender.• Destination addressIP address of the recipient.• Options/paddingOptional information and padding.
Dictionary of networking . 2014.
