"karthikbalaguru" wrote in message
news:1194380417.267229.213050@k35g2000prh.googlegr oups.com...
> Hi,
>
> TFTP is just a connectionless version of FTP that uses UDP for
> reducing the overhead and increasing the reliability. Why does TFTP
> does not require 2 ports ?
> How does TFTP manage to do the activities done by FTP with only
> 1 port ?
>
> That is,
> FTP (TCP based) use two ports (Port 20 and Port 21).
> Port 20 - For Data Stream . (data)
> Port 21 - For Control Stream (commands between FTP server and
> client)
> TFTP (UDP based) use only one port(Port 69) . Why ?
>
> Thx in advans,
> Karthik Balaguru


I love your scatter gun questioning. Sometimes well thought out, researched
and insightful. Sometimes lazy. It has been asked before, but how many
people are posting under the name Karthik Balaguru? Are you also
responsible for doubling the traffic on the comp.sys.arm group?

Back to the point:
http://en.wikipedia.org/wiki/Trivial...nsfer_Protocol

--
Regards,
Richard.

+ http://www.FreeRTOS.org
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In comp.arch.embedded FreeRTOS.org wrote:
>
> I love your scatter gun questioning. Sometimes well thought out, researched
> and insightful. Sometimes lazy. It has been asked before, but how many
> people are posting under the name Karthik Balaguru? Are you also
> responsible for doubling the traffic on the comp.sys.arm group?
>
> Back to the point:
> http://en.wikipedia.org/wiki/Trivial...nsfer_Protocol
>

Or perhaps
http://en.wikipedia.org/wiki/Luther_..._(nom_de_plume)



Maybe it's a whole bunch of wannabes trying to get their homework done

pete
--
pete@fenelon.com "irk the purists - if you've never then you ought."

In article , Pete Fenelon wrote:
>In comp.arch.embedded FreeRTOS.org wrote:
>>
>> I love your scatter gun questioning. Sometimes well thought out, researched
>> and insightful. Sometimes lazy. It has been asked before, but how many
>> people are posting under the name Karthik Balaguru? Are you also
>> responsible for doubling the traffic on the comp.sys.arm group?
>>
>> Back to the point:
>> http://en.wikipedia.org/wiki/Trivial...nsfer_Protocol
>>
>
>Or perhaps
>http://en.wikipedia.org/wiki/Luther_..._(nom_de_plume)
>
>
>
>Maybe it's a whole bunch of wannabes trying to get their homework done
>
>pete

Yep, and using the same name, just to make sure.
:--}

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On Nov 7, 1:34 am, "FreeRTOS.org" wrote:
> "karthikbalaguru" wrote in message
>
> news:1194380417.267229.213050@k35g2000prh.googlegr oups.com...
>
>
>
>
>
> > Hi,
>
> > TFTP is just a connectionless version of FTP that uses UDP for
> > reducing the overhead and increasing the reliability. Why does TFTP
> > does not require 2 ports ?
> > How does TFTP manage to do the activities done by FTP with only
> > 1 port ?
>
> > That is,
> > FTP (TCP based) use two ports (Port 20 and Port 21).
> > Port 20 - For Data Stream . (data)
> > Port 21 - For Control Stream (commands between FTP server and
> > client)
> > TFTP (UDP based) use only one port(Port 69) . Why ?
>
> > Thx in advans,
> > Karthik Balaguru
>
> I love your scatter gun questioning. Sometimes well thought out, researched
> and insightful. Sometimes lazy. It has been asked before, but how many
> people are posting under the name Karthik Balaguru? Are you also
> responsible for doubling the traffic on the comp.sys.arm group?
>
> Back to the point:http://en.wikipedia.org/wiki/Trivial...nsfer_Protocol
>

Thx for that info Richard.
The links were really useful and i walked through the RFC documents &
Internet.
Interesting

I have collected some info from those links that i have shared here :

TFTP
=====
TFTP uses a stop-and-wait-protocol (one connection).
Maximum Packet size is 512 bytes. It sends 512 bytes and wait for
the ack.
Each data packet contains one block of data, and must be
acknowledged by an
acknowledgment packet before the next packet can be sent
It has application based ACK. This slow back and forth process
causes it to be slow.

Any transfer begins with a request to read or write a file, which
also serves to request a connection. If the server grants the
request, the connection is opened and the file is sent in fixed
length blocks of 512 bytes.

* TFTP supports five types of packets :
opcode operation
1 Read request (RRQ)
2 Write request (WRQ)
3 Data (DATA)
4 Acknowledgment (ACK)
5 Error (ERROR)


FTP
=====
FTP uses out-of-band control, which means it uses a separate
connection for control and data
FTP uses sliding windows and bigger packets. (2 connections)
So FTP is faster.

The protocol requires that the control connections be open while
data transfer is in progress. It is the responsibility of the
user to request the closing of the control connections when
finished using the FTP service, while it is the server who takes
the action. The server may abort data transfer if the control
connections are closed without command.

control connection
The communication path between the USER-PI and SERVER-PI for
the exchange of commands and replies. This connection follows
the Telnet Protocol.

data connection
A full duplex connection over which data is transferred, in a
specified mode and type. The data transferred may be a part of
a file, an entire file or a number of files. The path may be
between a server-DTP and a user-DTP, or between two
server-DTPs.

The control connection follows
the Telnet protocol. At the initiation of the user, standard
FTP
commands are generated by the user-PI and transmitted to the
server process via the control connection. (The user may
establish a direct control connection to the server-FTP, from a
TAC terminal for example, and generate standard FTP commands
independently, bypassing the user-FTP process.) Standard replies
are sent from the server-PI to the user-PI over the control
connection in response to the commands.

The FTP commands specify the parameters for the data connection
(data port, transfer mode, representation type, and structure)
and
the nature of file system operation (store, retrieve, append,
delete, etc.). The user-DTP or its designate should "listen" on
the specified data port, and the server initiate the data
connection and data transfer in accordance with the specified
parameters. It should be noted that the data port need not be
in
the same host that initiates the FTP commands via the control
connection, but the user or the user-FTP process must ensure a
"listen" on the specified data port. It ought to also be noted
that the data connection may be used for simultaneous sending
and
receiving.

Interesting to find that FTP has vast features and hence designed
like
in that manner.

I came across the below info too which i suspect is not possible
with TFTP !!!

A user might wish to transfer files between
two hosts, neither of which is a local host. The user sets up
control connections to the two servers and then arranges for a
data connection between them. In this manner, control
information
is passed to the user-PI but data is transferred between the
server data transfer processes. Following is a model of this
server-server interaction.


Control ------------ Control
---------->| User-FTP |<-----------
| | User-PI | |
| | "C" | |
V ------------ V
-------------- --------------
| Server-FTP | Data Connection | Server-FTP |
| "A" |<----------------------> |
"B" |
-------------- Port (A) Port (B)
----------------


I think, this server-server interaction is not pssible with
TFTP .

Karthik Balaguru