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Network Working Group Jon Postel
Request for Comments: 894 ISI
April 1984
IP packet through experimental Ethernet network transmission standard
(RFC895 - A Standard for the Transmission of IP DataGrams over Experimental
Ethernet NetWorks
table of Contents
1. Introduction: 1
2. Frame format: 2
3. Address mapping: 2
4. Track format: 2
5. Bytes agreed: 2
6. Reference: 3
The status of this memo:
This RFC document describes a standard method for encapsulating IP [1] in experimental Ethernet [2]. This RFC document tells the ARP
A standard protocol of a network community.
1 Introduction:
This memo is used for experimental Ethernet of 3MB / s, 8-bit address. IP packet in 10MB / s, 48-bit address Ethernet
See [3] in the transmission process [3].
2. Frame format:
The IP packet is transmitted in a standard experimental Ethernet frame format. Ethernet frame type field must contain value 513 (100
1 eight into system). The frame data field is to include IP headers and IP data.
If necessary, the frame data field will be filled into the minimum length of the experimental Ethernet. This fill is not a IP package
Some, nor is it in the length field of the IP header.
The maximum length of the packet sent on the experimental Ethernet is 1536 bytes. It is recommended to achieve a package that supports maximum length.
The design of the gateway must be capable of receiving the maximum length of the package, and in the case of necessary, the excessive package can be separated. Such as
If a system does not receive the maximum length package, it should take the steps to reduce the bag length when sending, for example using TCP
Big segment length [4].
Note: Packets on Ethernet may no longer be the maximum of 576 bytes on the general Internet. even
When you send a packet on an Ethernet host to another Ethernet, you should pay attention. More appropriate
The method is to send a smaller packet to avoid unnecessarily splitting at the intermediate gateway. At this point, please
Refer to [4] to get more information.
3. Address mapping:
32-bit IP addresses are mapped to 8-bit experimental Ethernet addresses.
The easiest way is to use the last 8 bits of the host part of the IP address as the address on the experimental Ethernet. This is pushing
Recommended method.
Broadcast address:
The broadcast address on the Internet (the address on the local area is 48 full 1) can be mapped to the broadcast experiment Ethernet
Address (all 0).
4. Track format:
Some versions of UNIX 4.2BSD use a different mask method, in order to get better under VAX virtual memory structure
Performance. Compatible systems in the same Ethernet may be used in them.
The host does not require this way. No packet can be sent to other hosts in this way unless
Affirmative acceptor will be able to explain them.
(Note: Now the UNIX 4.2BSD system can always use tracking methods, or you may not use them, depending on the guided option. This situation hopes to be changed in the future. Theunix 4.2BSD system also uses all 0 Ethernet addresses
This will also be changed in the future. )
5. By section convention:
As described in Appendix B, in Internet Protocol Description [1], the IP packet sent to the Ethernet is 8 bits.
One byte.
6. Reference:
[1] Postel, J., "Internet Protocol", RFC-791, USC / INFORMATION
Sciences Institute, September 1981.
[2] Metcalfe, R. And D. Boggs, "Ethernet: Distributed Packet
Switch for Local Computer Networks, Communications of The ACM,
V.19, N.7, PP 395-402, July 1976.
[3] Hornig, C., "A Standard for the Transmission of IP DataGrams
Over Ethernet NetWorks, RFC-894, Symbolics Cambridge Research
Center, April 1984.
[4] Postel, J., "The TCP Maximum Segment Size Option and Related
Topics, RFC-879, USC / Information Sciences Institute, November 1983.
[5] Plummer, D., "An Ethernet Address Resolution Protocol", RFC-826,
Symbolics Cambridge Research Center, NOVEMBER 1982.
[6] Leffler, S., And M. Karels, "Trailer Encapsulations, RFC-893,
University of California at Berkeley, April 1984.
RFC895 - A Standard for the Transmission of IP DataGrams over Experimental Ethernet NetWorks
IP packet through experimental Ethernet network transmission standard
1
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