SUMMARY : LU6.2 via Token Ring

From: Andy Smith (
Date: Tue Sep 26 1995 - 23:16:45 CDT

My original question:
   I am attempting to use LU6.2 to transfer data via Token Ring to/from SUN
   and IBM mainframe. Everything is working OK, but it's very slow (1300 bytes
   per sec). Our Network people were expecting it to be 10 times faster or more.
   I have taken all the defaults for the configuration file.
   If anybody out there is using this method and getting a reasonable transfer
   rate, please could you send me a copy of your configuration files.
   We are running 2.1 Sunlink TRI/S, Peer-to-Peer 7.02 on SunOS 4.1.4 to an
   IBM3090 using VTAM 3.4.

The answer, from George Sheppard (SUN Support, Australia):

   He advised to make the following changes, which should to increase the
   transfer rate to about 7500 bytes per second.

   In the SUN configuration file set the following values:

   max_btu_rcv = 4096
   snd_max_ru_size = 4096
   rcv_max_ru_size = 4096

   In /etc/rc.local, there are some commands that are added during installation
   of TRI/S. Change the set_params value for "maximum frame size" to 4096.

   On the VTAM side, change the MAXDATA value for the PU to 4096.
   George also said that using 2048, instead of 4096, for the above values
   would also give a simlar transfer rate.

   Unfortunately, we weren't allowed to change the VTAM MAXDATA value, as it
   would affect other "things" on the Token Ring, so I can't tell you whether
   these recommendations have the desired effect!!

Andy Smith,
UNIX Systems Group,
Macquarie Bank

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