File:   IBMTOKEN.DOC
       Auth:   Brian Fisher
       Date:   October 3 1989
     
       Purp:   Notes on IBMTOKEN.COM, the 'Ethernet' packet driver
               for TCP/IP and NCSA Telnet.
     
========================================================================
     
       IBMTOKEN is an Ethernet packet driver for the IBM Token Ring
       Adapter card.  The IBM Lan support program must be installed before
       you use IBMTOKEN.
     
       CONFIG.SYS - to install the LAN Support program and increase the
       size of the stacks.  The default stack size is too small and leads
       to crashes.
     
       device=C:\PCLAN\DXMA0MOD.SYS
       device=C:\PCLAN\DXMC0MOD.SYS
       device=C:\PCLAN\DXMT0MOD.SYS
       stacks=9,512
     
       AUTOEXEC.BAT - to install IBMTOKEN and define NCSA config file:
     
       IBMTOKEN 0x61   0
       SET CONFIGTEL=C:\CONFIG.TEL
     
     
       CONFIG.TEL
     
       myip=xx.yy.zz.qq                # put your IP address here
       netmask=255.255.255.0           # use your network mask here
       hardware=packet                 # tell NCSA to use the packet driver
                                       # interface
       address=0                       # class for packet driver
       ioaddr=0x61                     # vector given to IBMTOKEN
     
       mtu=1500                        # max IBMTOKEN can transmit
       maxseg=1500                     # max IBMTOKEN can receive
       rwin=536                        # max if NCSA can't do IP fragments
     
     
       IBMTOKEN:
     
       IBMTOKEN <vector> <adapter>
     
       where    vector is the interrupt assigned to the packet driver
                interface
     
                adapter is 0 for the first adapter card, and 1 if the
                second adapter card is to be used.
     
     
     
       When IBMTOKEN installs, the following occurs:
     
               1)   DIR.INITIALIZE is called to initialize the adapter.
               2)   DIR.OPEN.ADAPTER is called to set up buffers for
                    IBMTOKEN.
               3)   RECEIVE is called to set up the receive service
                    routines.
               4)   DIR.STATUS is called to determine the address of the
                    adapter.
     
               If any of these calls fails, the installation is aborted.
     
               IBMTOKEN may not install properly if the token ring adapter
               has been in use by another program, and to closed properly.
               If this is the case, reboot and run IBMTOKEN.
     
     
       OPERATION:
     
       IBMTOKEN translates 'Ethernet' packet driver calls to 802.2 LLC
       format packets for transmission.  Currently it supports IP and
       ARP transmissions.  RARP and BOOTP probably won't work.
     
       IP packets are sent 'as is'.  ARP packets require a minor modification
       before they are sent.  The hwr address space value must be changed from
       1h to 6h.  On receive, the driver changes 6h back to 1h.  The size (60
       is min for Ether) must be set to 28 or some token hosts won't accept
       the transmission.
     
       Receive packets smaller than 60 bytes are rounded up so the upper
       level will accept them.
     
       Token Ring source routing.  When the upper level call back routine
       accepts a packet, its RIF is recorded in a table interal to IBMTOKEN.
       When IBMTOKEN sees the destination address requires a RIF, the
       info is pulled from the table and added to the MAC header for transmit.
     
       IBMTOKEN can handle a maximum of 32 source route entries.  One
       default entry is present for the 'broadcast' address.  The first
       source route received for an address is assumed to be the shortest.
       Subsequent source routes from the same host are ignored.
 
 
I upgraded my Dos to 3.3 (Zenith) and started having intermittent
lockups.  One of the Model 55SX machines down the hall was running Dos
4.00 and wouldn't run at all with the driver loaded.  I've tracked it
down to a stack overflow.  The default setting for STACKS is 9,128 in
Dos 3.3 and Dos 4.00.  When the system is servicing a hardware IRQ,
the stack is only 128 bytes.  Add a Token receive IRQ, and bang, the
system hangs.  You can fix the problem by setting STACKS=9,512 (the
512 is the important number here).
 
Date:         Thu, 12 Jul 90 14:25-0400
From: Brian.L.Fisher%QueensU.CA@clvm.clarkson.edu
To: "aka CLUTX.BITNET" <nelson@clutx.clarkson.edu>
Subject: IBM Token Ring Packet Driver
 
IBMTOKEN won't run with PC LAN.  It was designed so users on a couple of
our Token Ring networks could use NCSA Telnet (Clarkson version, recently
renamed CUTCP) to transfer files and log on to our IBM mainframe via the
campus backbone.  We don't use PC LAN and never will,  TCP/IP is the
network method of choice here.
 
I'm not familiar with Novell Netware BYU feature, so I can't really say.
 
IBMTOKEN is an FTP Ethernet Packet driver, but it DOES NOT transform ethernet
packets to token ring.  It performs a (for lack of a better term) 'sub router'
function.  It receives packets from the program via FTP packet driver interface
and re-encapsulates them for transmission on token ring.  Some packets must
be modified for transmission on token ring, ie. ARP hardware address space
field (ap$hrd) is transformed during transmission/reception.  Packets received
from the token ring are re-encapsulated in ethernet format and passed up to
the program.  The driver is designed for TCP/IP protocols only.  'Other'
ethernet protocols may or may not work, no guarantee.  Hope this helps.
---------------------------------------------------
Brian Fisher, Systems Programmer, Queens University
Computing & Communications Services,  Kingston, ONT
K7L 3N6. Dupuis Hall      Brian.L.Fisher@QueensU.CA
---------------------------------------------------