[comp.protocols.misc] protocols query

ynzhai@ecst.csuchico.edu (William Zhai) (11/13/90)

I don't know if this question has been discussed before or if it is
the right place to post it.

But could somebody tell me the difference among various protocols, such as
kermit, xmodem, ymodem, zmodem, uucp and ftp?

Please either e-mail me or post them in the group.
Thanks in advance.

william

-- 
william
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david@WUBIOS.WUSTL.EDU (David J. Camp) (11/13/90)

In Reply to this Note From: <William Zhai>
>
>I don't know if this question has been discussed before or if it is
>the right place to post it.
>
>But could somebody tell me the difference among various protocols, such as
>kermit, xmodem, ymodem, zmodem, uucp and ftp?

Those are all file-transfer protocols.  All but ftp originated for 
use with RS232 connections, but many can now run on top of other
protocols, such as TCP/IP.  The TCP/IP protocol support ftp
directly.

Kermit contentrates on protability.  Its claim to fame is that it
can transfer files from any system to any system regardless of the
communications link.

xmodem, ymodem, and zmodem are designed to get the most out
an RS232 connection.  They do not work as well on other kinds
of connections, or between oddball systems.  Some or all of
them require an 8-bit channel, whereas Kermit can use a 
7-bit channel when necessary.

ftp ONLY works in a TCP/IP environment.  It only works from
one host on a TCP/IP network to another host on the same network.
Of course, it can traverse routers that pass IP packets 
between adjacent networks running the same protocol.

You did not mention uuencode/xxencode.  These are encoders
that allow a binary file to be transmitted via electronic
mail.  There are many cases where electronic mail is the
ONLY path between two hosts, such as for BITNET and UUCP.
These encoders are important alternatives to the direct
protocols mentioned above.

>
>Please either e-mail me or post them in the group.
>Thanks in advance.
>
>william
>
>-- 
>william
>============================================================================
>                             _  _
>                           _ \\// _
>

david@wubios.wustl.edu             ^     Mr. David J. Camp
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