LARGE FILE TRANSFERS HANG WHEN USING TOKEN RING FROM TANDEM TO IBM.

BACKGROUND.

Communication between two BCOM partners can take place on any link that supports SNA's LU 6.2 (APPC) conversations. Token-Ring links can provide efficient high-bandwidth communication. A typical installation will have the IBM mainframe connected to the mainframe through a 3172, 3174 or 3745 while the Tandem will be connected through a 3616.

THE PROBLEM AND ITS SYMPTOM.

The problem appears when transferring large files between Tandem and IBM over a token-ring link. At a certain point during the transfer, the activity halts with no further activity (the number of blocks transferred freezes, i.e. there is no increase in the number of blocks transferred).

The only way out is to abort the request.

THE SOLUTION.

Tandem has identified a problem with TLAM that causes the previous behavior. An Interim product Modification (IPM) has been issued. The IPM# is 9376ABE (Class C). As of the date of publication of this technical note (May 13, 1996), there was no Tandem product Report (TPR) formally issued.

If you are experiencing this problem or a considering conversion to Token-Ring, please contact your Tandem support to obtain the fix.