.-HPRPSDLY--=--value_of_hprpsdly_start_option-. >>-+---------------------------------------------+------------->< '-HPRPSDLY--=--+-ps_delay-+-------------------' '-EEDELAY--'
| statements: | GROUP |
| dependencies: | Enterprise Extender connection network connections only |
| range: | 0 - 240 (in seconds) |
Specifies the time that elapses before RTP pipes enter the path switch state.
The ARB flow control algorithm is sensitive to minor variations in the round-trip time and to unpredictable response times 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 the Enterprise Extender (EE) connection network that is defined by this group. 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 Enterprise Extender (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 dial-in EE connections with associated PUs that are dynamically created, define this parameter on the model major node (DYNTYPE=EE) PU definition statement.
- When the EEDELAY value is specified, the value that is calculated for the HPR path-switch delay might be as long as 253 seconds.
- If a predefined EE connection is established between two EE endpoints before the VRN connection is established (using the same VIPA addresses), the VRN connection uses the established predefined EE connection. In this case, to control the HPRPSDLY value associated with the EE VRN, you must specify the HPRPSDLY operand on the EE PU definition statement (for example, on the switched PU definition). Optionally, you can specify the HPRPSDLY value as a VTAM start option.
- This operand can be useful when the RTP partner is on a node that is CPU-constrained or that 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 sessions that are using this RTP pipe.