Standard for the transmission of IP datagrams over experimental Ethernet networks (RFC0895)
Original Publication Date: 1984-Apr-01
Included in the Prior Art Database: 2000-Sep-13
Internet Society Requests For Comment (RFCs)
This memo applies to the Experimental Ethernet (3-megabit/second, 8-bit addresses). The procedure for transmission of IP datagrams on the Ethernet (10-megabit/second, 48-bit addresses) is described in .
Network Working Group Jon Postel
Request for Comments: 895 ISI
A Standard for the Transmission of IP Datagrams
over Experimental Ethernet Networks
Status of this Memo
This RFC specifies a standard method of encapsulating Internet
Protocol (IP)  datagrams on an Experimental Ethernet . This
RFC specifies a standard protocol for the ARPA Internet community.
This memo applies to the Experimental Ethernet (3-megabit/second,
8-bit addresses). The procedure for transmission of IP datagrams on
the Ethernet (10-megabit/second, 48-bit addresses) is described in
IP datagrams are transmitted in standard Experimental Ethernet
frames. The type field of the Ethernet frame must contain the value
513 (1001 octal). The data field contains the IP header followed
immediately by the IP data.
If necessary, the data field should be padded to meet the
Experimental Ethernet minimum frame size. This padding is not part
of the IP packet and is not included in the total length field of the
The maximum length of an IP datagram sent over an Experimental
Ethernet is 1536 octets. Implementations are encouraged to support
full-length packets. Gateway implementations MUST be prepared to
accept full-length packets and fragment them if necessary. If a
system cannot receive full-length packets, it should take steps to
discourage others from sending them, such as using the TCP Maximum
Segment Size option .
Note: Datagrams on the Ethernet may be longer than the general
Internet default maximum packet size of 576 octets. Hosts connected
to an Ethernet should keep this in mind when sending datagrams to
hosts not on the same Ethernet. It may be appropriate to send
smaller datagrams to avoid unnecessary fragmentation at intermediate
gateways. Please see  for further information on this point.
RFC 895 April 1984
The mapping between 32-bit Internet addresses to 8-bit Experimental
Ethernet addresses can be done several ways.
The easiest thing to do is to use the last eight bits of host number
part of the Internet address as the host's address on the
Experimental Ethernet. This is the recommended approach.
The broadcast Internet address (the address on that network with a
host part of all binary ones) should be mapped to the broadcast
Experimental Ethernet address (address zero).
Some versions of Unix 4.2bsd use a different encapsulation method in
order to get better network performance with the VAX virtual memory
architecture. Consenting systems on the same Ethernet may use this
format between themselves.
No host is required to implement it, and no datagrams...