427SEP 2004Ver. 1.2DP-1520P/1820P/1820E9.3.3. Internet ProtocolThe IP (Internet Protocol) operating at the OSI Network layer, is a connectionless protocol that providesdatagram service, and IP packets are most commonly referred to as IP data grams.It performs the following typical functions:1. Identifies the IP address2. Packet disassembly and reassembly of the IP datagram3. Routing of the IP addressTerms DetailVersion Currently version 4Internet HeaderLengthIP Header field lengthType Of Service Service priority requested by IP Datagram (3 bits are reserved forprecedence)ID Identification frame number for upper layer communicationFlags Packet disassembly informationFragment Offset Offset from most significant bitTime To Live Decrement the counter until 0 every time packet pass over the routerProtocol Upper layer protocol identification number. ie TCP (06h), UDP (11h)Header Checksum Checksum is used for error checking on the header dataSource Address Sender’s IP AddressDestination Address Destination’s IP AddressOption When implementedPadding Fill bit field to add up to 32 bitVersion InternetHeader Length Type Of Service Total Length4 byteFragment OffsetFlagsIDTime To Live Protocol Header ChecksumSource AddressDestination AddressOption + Padding (size varies)DataIP Datagram
