The LANRSPTMR and LANFRMRTY parameters

In your Systems Network Architecture (SNA) controller description, the LAN response timer (LANRSPTMR) and the LAN frame retry (LANFRMRTY) parameters work together to determine how soon and how often the system retransmits a frame.

LANRSPTMR defines how long to wait before retransmitting a frame to the remote station. LANFRMRTY specifies how many times to retransmit a frame. A system retransmits a frame when one of the following situations occurs:

• A frame was lost or damaged.
• The remote station does not respond because it is busy.
• The remote station is waiting to acknowledge the frame with an information frame of its own. (See LANACKTMR and LANACKFRQ for more information about the acknowledge timer).

After your system retransmits a frame a number of times (based on the number that is indicated by the LANFRMRTY parameter), the system notifies the user that an error occurred and disconnects itself from the remote station.

Performance problems:

The default values of the parameters are designed for a single LAN and can cause too many frame retransmissions when accessing a remote station through a remote bridge. The bridge might slow data traffic enough that your retransmit timer expires before the remote station's acknowledgment reaches you. Eventually, your system automatically disconnects itself because it retransmitted a frame too many times. If this is the case, you should increase the values of LANRSPTMR and LANFRMRTY.