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RECOMMENDATIONS REPORT
(Revised)
for
File Transfer Via PC Pursuit
(Oct 17, 1988)
Telenet Communication Corporation
Field Operations HQ Tech Support
Reston, Virginia
CONTENTS
PAGE
----
1.0 Introduction........................................... 1
2.0 Recommendations........................................ 2
3.0 File Transfer Procedures............................... 5
4.0 Summary................................................ 6
SECTION 1.: Introduction
Because of many customer complaints concerning PC Pursuit's inability
to allow file transfers, Field Operations was requested to provide
recommendations for file transfer via PC Pursuit. In compliance with
this request, this document provides the following:
* Recommendation on the best file transfer protocols to be used
with PC Pursuit.
* Recommendation on the hunt-confirm sequence and line parameters
which provide optimum performance of various protocols.
* The average transfer rates which can be expected using the
correct hunt-confirm sequence and optional parameter settings.
SECTION 2.: Recommendations
This section outlines the most common file transfer protocols used
with PC Pursuit. The performance of the protocols in the direct con-
nect and PC Pursuit environments are also indicated.
The following protocols were tested via the Chicago in-dial to the
Washington DC out-dial; the observations are summarized below.
XMODEM XMODEM XMODEM
PC Pursuit XMODEM file transfers performed at an average throughput of
30% when the correct hunt-confirm and terminal type was utilized.
XMODEM does not support flow control, therefore it is suggested that
the "relaxed" mode be invoked if the user's communications software
permits this feature.
YMODEM YMODEM YMODEM
The performance of YMODEM file transfers VIA PC Pursuit was found to
have an average throughput of 56% when the correct hunt confirm and
terminal type is employed. Although YMODEM does not support flow
control, it uses large 1024 byte packets which the network PAD handles
quite readily under normal conditions. As a result, YMODEM is rated
one of the faster protocols for file transfer via PC Pursuit.
WXMODEM WXMODEM WXMODEM
WXMODEM file transfers utilizing the correct hunt-confirm and terminal
type performed well with an average transfer rate of 52%. This
protocol is capable of handling flow control which enables it to
perform with better reliability in the PC Pursuit environment. Users
should be aware that an early version of PROCOMM is known to have a
software problem which can affect the performance of WXMODEM file
transfers.
KERMIT KERMIT KERMIT
An optimum average throughput of 47% was obtained by KERMIT file
transfers via PC Pursuit. The throughput was optimized by modifying
the packet size to 90 and adjusting the (host) window size to 16 (for
uploads). KERMIT software which supports the sliding window feature
performs with optimum efficiency in the PC Pursuit environment.
SEALINK SEALINK SEALINK
SEALINK file transfers via PC Pursuit performed exceptionally well
with an average throughput of 74% with the correct hunt-confirm and
terminal type. SEALINK supports flow control and was specifically
designed to operate in the networking environment.
ZMODEM ZMODEM ZMODEM
File transfers utilizing ZMODEM protocol via PC Pursuit yielded an
average transfer rate of 61%. ZMODEM performs well in the PC Pursuit
environment, however; the local configuration for ZMODEM file trans-
fers proved to be cumbersome and difficult for the user. ZMODEM re-
quires several parameters to be set locally and on the local pad.
These parameter settings can vary depending on the type of machine and
the type of communications software. The X.3 PAD parameters which
should be employed are 1:0,4:10,5:1,7:8,12:1. In addition, flow con-
trol (XON/XOFF) should be enabled at the user PC. Because of the
difficulty in configuring ZMODEM for file transfer, it is recommended
that only seasoned computer users attempt ZMODEM file transfers via PC
Pursuit.
The following page summarizes file transfer performance of the
protocols tested. The protocols are listed in order (PCP best to
worst) in two categories: 1) performance via direct connect, 2) per-
formance via PC Pursuit utilizing the recommended hunt confirm and
parameter settings shown. It should be noted that the optional
parameters need only be employed if a user experiences problems with
transferring a particular file.
SECTION 3.: File Transfer Procedures
This section outlines the step by step procedure for executing file
transfers via PC Pursuit. These procedures must be followed exactly to
achieve optimum transfer rates. The optional X.3 parameters shown on
the previous page indicates the parameters which provide the best
transfer rate.
STEP 1.: Set PC communications software to 8 bits, no parity,
1 stop bit, full duplex. Depending on the type of protocol
to be used, disable or enable local (XON/XOFF) flow
control.
STEP 2.: Dial local rotary with the communications software
set at the desired speed.
STEP 3.: Upon answer use the correct hunt confirm sequence:
At 300/1200bps use - <CR D CR>
At 2400bps - <@ D CR>
NOTE: "D" MUST BE UPPER CASE.
STEP 4.: At prompt "TERMINAL = " enter <D1> and return.
STEP 5.: At the "@" prompt enter the destination mnemonic,
out-dial speed, ID and password. It is important
that out-dial speed matches in-dial speed.
DO NOT MIX IN-DIAL AND OUT-DIAL SPEEDS.
STEP 6.: If pad X.3 parameters are to be changed, do so
at this point by entering <@ CR>. Set parameters as
prescribed. Return to out-dial port by entering
<CONT>.
An example of the proper syntax for modifying X.3 PAD
parameters would be "SET 7:8,1:0." To display the current
PAD parameter settings, the user should enter "PAR?."
These are only two of many user commands available. Many
of the user commands are clearly defined in the Telenet
document "How to Use Telenet's Asynchronous Dial Service."
STEP 7.: Upon connecting to the destination pad, insure
communication with the out-dial modem by entering <ATZ>.
The destination modem will respond with "OK".
STEP 8.: Enter <ATD> and the local number you wish to dial.
STEP 9.: Queue host file transfer and start file transfer.
Please note that these are the basic steps needed to achieve success-
ful file transfers. Since communications software may vary from
package to package, additional steps may be needed to initiate the
start of the file transfer at the user software level.
SECTION 4.: Summary
Extensive testing has resulted in identifying the expected performance
of six file transfer protocols when used with PC Pursuit. These
protocols have been determined to perform satisfactorily with PC
Pursuit when the correct hunt-confirm, terminal type and parameters
are employed.
It is the recommendation of Field Operations that customers be in-
formed of the correct logon procedures and the protocols which provide
the most reliable file transfers. Customers should also be reminded
that PCP users can expect a small degree of network delay which is
considered a common characteristic of packet switched networks. In
addition, users should also be informed that poor quality voice grade
telephone lines can adversely affect file transfer sessions.
Field Operations is one of many Telenet groups dedicated to providing
customers with complete support for PC Pursuit. Field Operations will
offer assistance with file transfer problems providing the customer is
willing to release a copy of the problem software as well as provide
the pertinent information necessary to resolve the problem.
Because problems can vary in nature, the information required to
resolve problems can differ from one problem to the next. But at the
very least, the following information will be required:
* Type of communication software
* Type of PC, make, model
* Type of modem
* Call origin
* Call destination
* Speed in
* Speed out
* Type of session
* Time of failure
* Date of Failure
* Point of failure in session
* Out-dial number
* Network Address (if possible)
* Copy of PC Software (in some cases)
Additional information may be required depending on the nature of
the problem.
FILE TRANSFER
PERFORMANCE STATISTICS
PERFORMANCE STATISTICS DIRECT CONNECT
General Communication Parameters = 8 bits
1 stop bit
N no parity
Terminal Type = D1
| PERFORMANCE STATISTICS DIRECT CONNECT |
| |
| |
| XFR |
| PROTOCOL SPEED SECONDS CPS BPS RATE |
|======================================================|
| |
| SEALINK UP 1200 ***517 87.15 871.49 73% |
| SEALINK UP 2400 ***270 166.87 1668.74 70% |
| SEALINK DN 1200 ***428 105.27 1052.71 88% |
| SEALINK DN 2400 ***230 195.90 1958.96 82% |
| |
| ZMODEM UP 1200 ***408 110.43 1104.31 92% |
| ZMODEM UP 2400 ***201 224.16 2241.59 93% |
| ZMODEM DN 1200 ***391 115.23 1152.33 96% |
| ZMODEM DN 2400 ***195 231.06 2310.56 96% |
| |
| YMODEM UP 1200 **259 102.80 1027.95 86% |
| YMODEM UP 2400 **126 211.30 2113.02 88% |
| YMODEM DN 1200 **244 109.11 1091.15 91% |
| YMODEM DN 2400 **130 204.80 2048.00 85% |
| |
| WXMODEM UP 1200 **277 96.12 961.16 80% |
| WXMODEM UP 2400 **159 167.45 1674.47 70% |
| WXMODEM DN 1200 **405 65.74 657.38 55% |
| WXMODEM DN 2400 **131 203.24 2032.37 85% |
| |
| KERMIT UP 1200 **356 74.79 747.87 62% |
| KERMIT UP 2400 **211 126.18 1261.80 53% |
| KERMIT DN 1200 **322 82.68 826.83 69% |
| KERMIT DN 2400 **178 149.57 1495.73 62% |
| |
| XMODEM UP 1200 **259 102.80 1027.95 86% |
| XMODEM UP 2400 **140 190.17 1901.71 79% |
| XMODEM DN 1200 **268 99.34 993.43 83% |
| XMODEM DN 2400 **146 182.36 1823.56 76% |
======================================================
**File size = 26624 ***File size = 45056
FILE TRANSFER
PERFORMANCE STATISTICS
PERFORMANCE STATISTICS VIA PCP
General Communication Parameters = 8 bits
1 stop bit
N no parity
Terminal Type = D1
| PERFORMANCE STATISTICS VIA PCP |
| |
| HUNT ITI |
| |
| XFR CONFIRM FLOW X.3 PAD |
| PROTOCOL SPEED SECONDS CPS BPS RATE SEQUENCE CONTROL PARAMETERS NOTES |
|================================================================================================ ===========================|
| |
| SEALINK UP 1200 ***561 80.31 803.14 67% CR D CR XON/XOFF *7:8,1:0 End-to-End flow control on |
| SEALINK UP 2400 ***300 150.19 1501.87 63% @ D CR XON/XOFF *7:8,1:0 End-to-End flow control on |
| SEALINK DN 1200 ***447 100.80 1007.96 84% CR D CR XON/XOFF *7:8,1:0 End-to-End flow control on |
| SEALINK DN 2400 ***231 195.05 1950.48 81% @ D CR XON/XOFF *7:8,1:0 End-to-End flow control on |
| |
| ZMODEM UP 1200 ***622 72.44 724.37 60% CR D CR XON/XOFF *1:0,4:10,5:1,7:8,12:1 End-to-End flow control on |
| ZMODEM UP 2400 ***363 124.12 1241.21 52% @ D CR XON/XOFF *1:0,4:10,5:1,7:8,12:1 End-to-End flow control on |
| ZMODEM DN 1200 ***573 78.63 786.32 66% CR D CR XON/XOFF 1:0,4:10,5:1,7:8,12:1 End-to-End flow control on |
| ZMODEM DN 2400 ***288 156.44 1564.44 65% @ D CR XON/XOFF 1:0,4:10,5:1,7:8,12:1 End-to-End flow control on |
| |
| YMODEM UP 1200 **443 60.10 600.99 50% CR D CR NONE *7:8,1:0 |
| YMODEM UP 2400 **200 133.12 1331.20 55% @ D CR NONE *7:8,1:0 |
| YMODEM DN 1200 **335 79.47 794.75 66% CR D CR NONE *7:8,1:0 |
| YMODEM DN 2400 **211 126.18 1261.80 53% @ D CR NONE *7:8,1:0 |
| |
| WXMODEM UP 1200 **480 55.47 554.67 46% CR D CR XON/XOFF *7:8,1:0 End-to-End flow control on |
| WXMODEM UP 2400 **258 103.19 1031.94 43% @ D CR XON/XOFF *7:8,1:0 End-to-End flow control on |
| WXMODEM DN 1200 **363 73.34 733.44 61% CR D CR XON/XOFF *7:8,1:0 End-to-End flow control on |
| WXMODEM DN 2400 **193 137.95 1379.48 57% @ D CR XON/XOFF *7:8,1:0 End-to-End flow control on |
| |
| KERMIT UP 1200 **597 44.60 445.96 37% CR D CR XON/XOFF *7:8,1:0,5:1,12:1 |
| KERMIT UP 2400 **298 89.34 893.42 37% @ D CR XON/XOFF *7:8,1:0,5:1,12:1 |
| KERMIT DN 1200 **389 68.44 684.42 57% CR D CR XON/XOFF *7:8,1:0,5:1,12:1 |
| KERMIT DN 2400 **196 135.84 1358.37 57% @ D CR XON/XOFF *7:8,1:0,5:1,12:1 |
| |
| XMODEM UP 1200 **734 36.27 362.72 30% CR D CR NONE *7:8,1:0 |
| XMODEM UP 2400 **424 62.79 627.92 26% @ D CR NONE *7:8,1:0 |
| XMODEM DN 1200 **638 41.73 417.30 35% CR D CR NONE *7:8,1:0 |
| XMODEM DN 2400 **373 71.38 713.78 30% @ D CR NONE *7:8,1:0 |
=============================================================================================== ============================
* Optional PAD parameters which optimize performance **File size = 26624 ***File size = 45 56
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