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Network Working Group IRA Winston
Request for Comments: 948 University of Pennsylvania
June 1985
IP Datashers Two Methods Transfer by IEEE802.3 network
(RFC948 --TWO Methods for the Transmission of IP DataGrams
Over IEEE 802.3 NetWorks)
The state of this memo
This document describes two methods of encapsulating Internet Communication Protocol (IP) [1] on the IEEE 802.3 network [2]. This one
RFC puts a recommendation agreement to the ARPA-Internet community. And also need to be discussed and improved. this
The release of the memo is not restricted.
table of Contents
Introduction 2
Ethernet compatibility mode 2
IEEE802.2 / 802.3 compatibility mode 2
Structural form 2
Address image 3
Static Table 3
Dynamic discovery 3
Broadcast address 3
Tracking format 3
Byte order 4
Ending
Reference 4
Introduction
IEEE 802 option defines the processing of local area network defined by ISO open system interconnect model (ISO / OSI)
A series of standards for physical layer and data link layers. Several physical layer standards (802.3, 802.4 and 802.5) [2, 3,
4] and a data link layer standard (802.2) [5] has been set. IEEE physical layer standard detailed
The ISO / OSI physical layer and the media access control sub-layer of the ISO / OSI data link layer. 802.2 Data Link Layer Standard Details
The logical link control sub-layer in the ISO / OSI data link layer is described.
802.3 The standard is based on the second edition Ethernet standard [6]. Ethernet physical layer and 802.3 physical layer in all
The practical application is compatible, however, Ethernet data link layers and 802.2 / 802.3 data link layers are not compatible
of.
There are many Ethernet network devices to transmit IP datagrams using the Ethernet compatible standards described in [7]. IEEE 802.3
Physical layer compatible connections can be added to these networks, using an Ethernet without violating 802.3 standards
Data Link Layer Compatibility Mode Transfer IP Datasters. Two choices, using an 802.2 / 803.3 data link layer compatible mode
Transfer IP datagram.
Ethernet compatibility mode
IEEE802.3 Network To achieve and Ethernet compatibility, the IEEE 8 must be used to use 48bit physical addresses and bandwidth of 10m / s.
The head of the IEEE 802.3 packet and the head of the Ethernet data package is exactly the same, except for the allocation meaning of the first section. In a
This paragraph is used as a protocol type segment in the head of an Ethernet data package, and this paragraph in a 802.3 packet is
It is used as a length section. The value of the maximum length segment allowed in 10m / s 802.3 is 1500.802.3
The length of the data packet will be ignored, discarded or customized by the length segment of the data packet.
Therefore, when the protocol type is used to exceed 1500, the length segment can be used as the protocol type segment by the custom mode.
The protocol types of IP, ARP, and tracking are more than 1500. Using this technique, the method of transmitting IP datagrams on an Ethernet network describing the IP datagram in Ethernet compatibility mode on the IEEE 802.3 network.
IEEE802.2 / 802.3 compatibility mode
structure type
The IP datagram is transmitted in the standard 802.2 / 802.3 logical link control layer type 1. Countless 802.2 Destination Service Access
Ask the information header of the question point and source service access point format set to 96, IEEE specifies the value of global access service points for IP.
Data segments include IP data that follows after IP headers.
The minimum size limit for IEEE 802.3 packets is based on network bandwidth. Data segment will be filled when needed
(Use an octal zero) to suit the 902.3 minimum structure size. These filled zero does not belong to the IP packet,
Not included in the total length range of IP headers.
The maximum size restriction of the IEEE 802.3 packet is based on network bandwidth. Enforce the full length data package
Row.
The execution of the gateway must be prepared to accept a full length packet and crush them when necessary.
The execution of the host should be prepared to accept a full length data package, but the host does not necessarily need to send a length of more than 576
A octa-based byte data is reported to be prepared to accept them very clearly. Host can be in TCP
On the basis of the application, her size is transmitted through the TCP maximum segmentation size option [9].
Note: Data reports may exceed 576 octal data on the default data report size of ordinary Internet on the 802.3 network.
byte. The host is connected to an 802.3 network, when sending data is not on the host on the same 802.3 network
It should be told this. Perhaps a small bit of datagram is perhaps avoiding unnecessary intermediate gateway segmentation. Please see this
Further information.
Address image
32BIT's Internet Address Image to 16bit or 48bit 802.3 address can have several implementations. Can make
With a static table, you can use a dynamic discovery program.
Static table
Each host can provide a table of all other 802.3 addresses and Internet addresses on the local area.
Dynamically discovery
32bit Internet address and 802.3 can be implemented by a protocol similar to the Ethernet Address Translation Protocol (ARP) [10].
The image between the address. In some Internet networks, the Internet address is assigned freely. Each host is completed
Need to know his own Internet address, reply to the appropriate 802.3 address translation packet. It can also be in need
Use ARP to convert the Internet address to 802.3.
Broadcast address
Internet Broadcast Address (all host parts of the network address are binary "1") should be imaged to 802.3
Broadcast addresses (all binary "1").
Strongly recommended using ARP dynamic discovery procedures.
Track format
Some of UNIX 4.2BSD use different package modes to get better online in VAX virtual memory structure
Weigong. This format is taken in these systems in the same 802.3 network. Tracking package mode can be in [11]
turn up.
Byte order
In Appendix B, the IP datagram is described in detail with the Internet Communication Protocol in Appendix B.
Bytes are transmitted through 802.2 / 802.3 networks.
end
Both package patterns can be mixed in the same LAN; however, this will split the network into two incompatible subnets.
The host on a network supports two modes and works just between the two subnets as the gateway; however, this
It will introduce an important punitive operation, which should be avoided.
IEEE 802.2 / 802.3 Compatible Package mode is better than Ethernet compatibility mode, because IEEE802.2 and IEEE802.3
The standard has been accepted by the United States and the world, and the same package mode can be used in other IEEE802
Physical layer operation. However, there are many existing devices must use the IP protocol on Ethernet and from Ethernet to
Control conversion of IEEE802.2 / 802.3.
Finally, all new operations should allow package mode static selection and all existing operations are guaranteed to be static.
The correct correct should be modified. During transmission, all hosts on the same network should be compatible with Ethernet.
mode. After the existing existing operation is added, after 802.2 / 802.3 support, IEEE 802.2 / 802.3 mode will
Will be used and the conversion will be completed.
reference
[1] Postel, J. "Internet Protocol". RFC-791, USC / INFORMATION
Sciences Institute, September 1981.
[2] The Institute of Electronics and Electronics Engineers, Inc.
IEEE Standards for Local Area Networks: Carrier Sense Multiple
Access with Collision Detection (CSMA / CD) Access Method and
Physical Layer Specifications ". The Institute of Electronics
And Electronics Engineers, Inc., New York, New York, 1985.
[3] The Institute of Electronics and Electronics Engineers, INC.
IEEE Standards for Local Area Networks: Token-Passing Bus
Access Method and Physical Layer Specifications ". The Institute
Of Electronics and Electronics Engineers, Inc., New York, New
York, 1985.
[4] The Institute of Electronics and Electronics Engineers, Inc.
IEEE Standards for Local Area Networks: Token Ring Access
Method and Physical Layer Specifications ". The Institute of
Electronics and Electronics Engineers, Inc., New York, New York,
1985.
[5] The Institute of Electronics and Electronics Engineers, Inc.
"IEEE Standards for Local Area Networks: Logical Link Control".
The Institute of Electronics and Electronics Engineers, Inc.,
NEW YORK, New York, 1985.
[6] "The Ethernet, Physical and Data Link Layer Specifications,
Version 2.0 ". DIGITAL Equipment Corporation, Intel Corporation,
And Xerox Corporation, 1982.
[7] Hornig, C. "A Standard for the Transmission of IP DataGrams
Over Ethernet NetWorks ". RFC-894, Symbolics Cambridge Research
Center, April 1984.
[8] Reynolds, J., And Postel, J. "Assigned NumBers". RFC-943,
USC / Information Sciences Institute, April 1985. [9] Postel, J. "TCP Maximum Segment Size Option and Related
Topics ". RFC-879, USC / Information Sciences Institute,
November 1983.
[10] Plummer, D. "An Ethernet Address Resolution Protocol".
RFC-826, Symbolics Cambridge Research Center, NOVEMBER 1982.
[11] Leffler, S., And Karels, M. "Trailer Encapsulations". RFC-893,
University of California at Berkeley, April 1984.
RFC948-Two Methods for the Transmission of IP DataGrams Over IEEE 802.3 Networks over IEEE 802.3
Networks IP Datashers Two Methods Transfer by IEEE802.3 network
1
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