The LAN window step (LANWDWSTP) parameter of your SNA controller description determines whether the number of outstanding frames are reduced during network congestion.
Parameter LANMAXOUT determines the initial value for the number of outstanding frames.
The default *CALC value for LANWDWSTP is *NONE.
If the value for LANWDWSTP parameter is too small or is *NONE, the network congestion takes longer to subside. For more information about network congestion, see the discussion of the dynamic window algorithm in book Token-Ring Network Architecture Reference (SC30–3374).