Resolving The Problem

There are two approaches to solving this problem. First, CAPACITY can be specified as the number closest to the actual bandwidth of the link without exceeding the bandwidth. The connection will not experience any data loss due to overloading its maximum bandwidth. However, the connection will never fully utilize the bandwidth available.

The second solution is to code CAPACITY as the number closest to the actual bandwidth of the link but, exceeding the actual bandwidth. This solution will result in the link being overloaded with data as the ARB algorithm tries to maximize the data flow on the link. The ARB algorithm will determine the actual data rate of link and maximize its potential. There will be a slight performance issue as ARB approaches the maximum bandwidth of the link. However, this should be short lived.

NOTE:

When determining the data flow on a link VTAM will start with 5% of the coded CAPACITY value and ramp up data flow until the coded CAPACITY value or the actual link capacity is reached.

Also, note the differences in the values coded for CAPACITY and the values which will be displayed in the D NET,TOPO and D NET,TGPS commands. These values are listed in the z/OS Communications Server SNA Resource Definition Reference.

Apply the PTFs for HIPER APAR OA20394 if you are running z/OS 1.8 or earlier.