RFC263 "Very Distant" Host interface

0263 "Very Distant" Host interface. A.M. McKenzie. December 1971. (Format: TXT=3914 bytes) (Status: UNKNOWN)

日本語訳
RFC一覧

参照

Network Working Group                             A. McKenzie
Request for Comments #263                         BBN
NIC #7811                                         17 December 1971
Categories:  B.1, C.2, I.1
Updates:  none
Obsoletes:  none

                     "VERY DISTANT" HOST INTERFACE

     The normal method of connecting a Host computer to the ARPA
Network is, and will continue to be, placing an IMP at the Host
site and making a short-distance hard-wire connection.  However,
during the past several months we have become increasingly aware
of the occasional desire to interface a Host to some IMP via a
long-distance connection (where long-distance, in this context,
is any cable run longer than 2000 feet but may typically be tens
of miles) via either a hard-wire or telephone circuit.  We believe
that any good solution to the general problem of interfacing Hosts
to IMPs must satisfy at least the following criteria:

     1)  The characteristics of the connection should be such
         that the undetected error rate can be expected to be
         extremely low.

     2)  The bandwidth of the connection should not be
         intrinsically limited to a low value.

     3)  The nature of the connection should be such that the
         Host may establish multiple network "conversations",
         i.e., it should have all the power of a normal Host
         connection.

These criteria were briefly discussed in our earlier RFC #241
(NIC #7671), "Connecting Computers to MLC Ports."

     After a careful review of the various possibilities for "very
distant" Host connection, we have arrived at a preliminary design
for this type of interface which we believe should prove
satisfactory with regard to the criteria above.  Although
detailed specifications will not be available for some time, the
basic elements of the design are as follows:










                                                                [Page 1]

Transmissions will be full-duplex and will use the same
Binary Synchronous format that is presently used in inter-IMP
communication.  At the IMP end, a hardware interface identical
in type, but not necessarily in speed, to the usual IMP 50 kilobit
modem interface will be used.  This interface frames blocks of
outgoing data with special characters and appends a 24 bit cyclic
redundancy check (CRC).  It de-frames and checks incoming blocks
which must be of similar format.  The Host must provide mating
formatting, de-formatting and checking facilities at its end.

     In conjunction with the CRC creation and checking, the IMP
will be provided with a small amount of "retransmission" software
as a front (i.e., Host side) end for the usual Host/IMP interface
software. The retransmission scheme, although not presently
completely defined, will be based on positive acknowledgment/
timeout techniques.

     The Host will be required to provide a front (i.e. IMP side)
end to its NCP which can generate CRCs and test for CRC errors,
provide simple retransmission logic, etc.  This front end may be
implemented in Host software, by means of special purpose hardware,
in a minicomputer, or in any other way which the Host organization
finds reasonable.

     This new type of interface will be completely documented,
from both a hardware and software point of view, as soon as the
detailed design is completed.  This documentation will probably
take the form of an update to BBN report No. 1822.

     We will be happy to discuss this type of interface with any
interested organization, although it should be remembered that
detailed design is not yet completed.

AMcK:jm

       [ This RFC was put into machine readable form for entry ]
       [ into the online RFC archives by BBN Corp. under the   ]
       [ direction of Alex McKenzie.                   12/96   ]













                                                                [Page 2]

一覧

 RFC 1〜100  RFC 1401〜1500  RFC 2801〜2900  RFC 4201〜4300 
 RFC 101〜200  RFC 1501〜1600  RFC 2901〜3000  RFC 4301〜4400 
 RFC 201〜300  RFC 1601〜1700  RFC 3001〜3100  RFC 4401〜4500 
 RFC 301〜400  RFC 1701〜1800  RFC 3101〜3200  RFC 4501〜4600 
 RFC 401〜500  RFC 1801〜1900  RFC 3201〜3300  RFC 4601〜4700 
 RFC 501〜600  RFC 1901〜2000  RFC 3301〜3400  RFC 4701〜4800 
 RFC 601〜700  RFC 2001〜2100  RFC 3401〜3500  RFC 4801〜4900 
 RFC 701〜800  RFC 2101〜2200  RFC 3501〜3600  RFC 4901〜5000 
 RFC 801〜900  RFC 2201〜2300  RFC 3601〜3700  RFC 5001〜5100 
 RFC 901〜1000  RFC 2301〜2400  RFC 3701〜3800  RFC 5101〜5200 
 RFC 1001〜1100  RFC 2401〜2500  RFC 3801〜3900  RFC 5201〜5300 
 RFC 1101〜1200  RFC 2501〜2600  RFC 3901〜4000  RFC 5301〜5400 
 RFC 1201〜1300  RFC 2601〜2700  RFC 4001〜4100  RFC 5401〜5500 
 RFC 1301〜1400  RFC 2701〜2800  RFC 4101〜4200 

スポンサーリンク

OSのバージョンと特徴

ホームページ製作・web系アプリ系の製作案件募集中です。

上に戻る