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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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