length octet, the pointer octet, and length-3 octets of route
        data.  The third octet is the pointer into the route data
        indicating the octet which begins the next area to store a route
        address.  The pointer is relative to this option, and the
        smallest legal value for the pointer is 4.

        A recorded route is composed of a series of internet addresses.
        Each internet address is 32 bits or 4 octets.  If the pointer is



 

September 1981                                                          
                                                       Internet Protocol
                                                           Specification



        greater than the length, the recorded route data area is full.
        The originating host must compose this option with a large
        enough route data area to hold all the address expected.  The
        size of the option does not change due to adding addresses.  The
        intitial contents of the route data area must be zero.

        When an internet module routes a datagram it checks to see if
        the record route option is present.  If it is, it inserts its
        own internet address as known in the environment into which this
        datagram is being forwarded into the recorded route begining at
        the octet indicated by the pointer, and increments the pointer
        by four.

        If the route data area is already full (the pointer exceeds the
        length) the datagram is forwarded without inserting the address
        into the recorded route.  If there is some room but not enough
        room for a full address to be inserted, the original datagram is
        considered to be in error and is discarded.  In either case an
        ICMP parameter problem message may be sent to the source
        host [3].

        Not copied on fragmentation, goes in first fragment only.
        Appears at most once in a datagram.

      Stream Identifier

        +--------+--------+--------+--------+
        |10001000|00000010|    Stream ID    |
        +--------+--------+--------+--------+
         Type=136 Length=4

        This option provides a way for the 16-bit SATNET stream
        identifier to be carried through networks that do not support
        the stream concept.

        Must be copied on fragmentation.  Appears at most once in a
        datagram.














 

                                                          September 1981
Internet Protocol
Specification



      Internet Timestamp

        +--------+--------+--------+--------+
        |01000100| length | pointer|oflw|flg|
        +--------+--------+--------+--------+
        |         internet address          |
        +--------+--------+--------+--------+
        |             timestamp             |
        +--------+--------+--------+--------+
        |                 .                 |
                          .
                          .
        Type = 68

        The Option Length is the number of octets in the option counting
        the type, length, pointer, and overflow/flag octets (maximum
        length 40).

        The Pointer is the number of octets from the beginning of this
        option to the end of timestamps plus one (i.e., it points to the
        octet beginning the space for next timestamp).  The smallest
        legal value is 5.  The timestamp area is full when the pointer