.-HPRPSDLY--=--value_of_hprpsdly_start_option-. >>-+---------------------------------------------+------------->< '-HPRPSDLY--=--+-ps_delay-+-------------------' '-EEDELAY--'
| statements: | PU |
| dependencies: | DYNTYPE=EE only |
| range: | 0 - 240 (in seconds) |
Specifies the time that elapses before RTP pipes enter the patch switch state.
The ARB flow control algorithm is sensitive to minor variations in the round-trip time and to unpredictable response time from the partner. This sensitivity might cause RTP endpoints to prematurely enter the path switch state. Although this situation does not affect availability, it does consume CPU cycles and it also causes a significant number of path switch messages to be written to the console log.
The HPRPSDLY operand is valid only for RTP pipes that are directly attached to an Enterprise Extender (EE) connection that uses this model PU definition to dynamically create its associated PU. This operand affects only path switches that are the result of an unresponsive partner (path switches that generate the message IST1818I PATH SWITCH REASON: SHORT REQUEST RETRY LIMIT EXHAUSTED). The HPRPSDLY operand does not control path switches that are initiated as a result of a TG INOP, F RTP commands, or the PSRETRY function. If you do not code this operand, VTAM® uses the value that you coded on the HPRPSDLY start option.
- HPRPSDLY=ps_delay
- Specifies the number of seconds that RTP pipes must delay prior to entering the path switch state. During this time, the RTP endpoint periodically tries to contact the partner in an effort to avoid switching paths. The value 0 indicates that the RTP nodes enter the path switch state when a predetermined number of retry attempts have been unsuccessful.
- HPRPSDLY=EEDELAY
- Specifies that VTAM calculates the number of seconds that RTP pipes must delay prior to entering the path switch state. The value that is calculated allows enough time for the EE keep-alive mechanism to cause the EE connection to become inoperative if connectivity to the partner is lost. Unnecessary path switches are avoided while EE determines whether there is a loss of connectivity to the partner.
For predefined EE connections, define this parameter on the PU definition in the switched major node. For EE connection networks, define this parameter on the connection network GROUP definition statements in the EE XCA major node.
Result: When the EEDELAY value is specified, the value that is calculated for the HPR path-switch delay might be as long as 253 seconds.
- This operand can be useful when the RTP partner is on a node that is CPU-constrained or is running in a virtualized environment. In both of these situations, allowing additional time for the RTP partner to respond might avoid unnecessary processing associated with a path switch.
- If alternate routes exist, specifying a long delay time might cause unnecessary delays for the session that are using this RTP pipe.