UNRCHTIM start option


                           (1)                              
   .-UNRCHTIM--=--(0,10)--------------------------------.   
>>-+----------------------------------------------------+------><
   '-UNRCHTIM--=--+-unreachable_time------------------+-'   
                  +-(,partner_limit)------------------+     
                  '-(unreachable_time ,partner_limit)-'

Notes:

UNRCHTIM is meaningful only if the NODETYPE start option is also used.

range:

unreachable_time:

partner_limit:

0, or 10-65535

5-65535

Specifies the options associated with Enterprise Extender connection network reachability awareness.

There are three allowed formats for coding start option UNRCHTIM:

UNRCHTIM=unreachable_time
UNRCHTIM=(unreachable_time ,partner_limit)
UNRCHTIM=(,partner_limit)

unreachable_time: Specifies the default number of seconds that a partner node for a session path through an Enterprise Extender connection network is considered unreachable after certain Enterprise Extender connection network failures. During this period, the path through the Enterprise Extender connection network to this partner node is not considered for new sessions or HPR path switches.
partner_limit: Specifies the limit for the number of unreachability records that can be associated with an Enterprise Extender connection network before that connection network is considered unusable for session route selection. No paths through the Enterprise Extender connection network will be considered for new sessions or HPR path switches until the number of unreachability records falls below 80% of the partner_limit value. The number of unreachability records associated with an Enterprise Extender connection network virtual routing node (VRN) can be displayed with a DISPLAY TOPO,LIST=UNRCHTIM,VRN=virtual_node command.
Result: Unreachability records are not maintained on an end node. They are maintained only by the end node's network node server. Therefore, the partner_limit value is ignored if specified on an end node.

A partner node is determined to be unreachable when a dial failure occurs across an Enterprise Extender connection network or when an INOP of an existing connection through an Enterprise Extender connection network is detected. UNRCHTIM is meaningful only if the NODETYPE start option is also used.

UNRCHTIM is meaningful only for Enterprise Extender connection networks. You can override the UNRCHTIM unreachable_time start option value for individual Enterprise Extender connection networks by coding UNRCHTIM=unreachable_time on the PORT or GROUP statement that defines each connection network in the Enterprise Extender External Communications Adapter (XCA) major node. The UNRCHTIM partner_limit value cannot be coded on the PORT or GROUP statements. See z/OS Communications Server: SNA Network Implementation Guide for additional information about performance considerations with UNRCHTIM.

Note:

If the UNRCHTIM start option is not specified, the default unreachable_time value is 0, which indicates that paths through Enterprise Extender connection networks will always be considered for routing.
A minimum (nonzero) value of 10 seconds is set for the UNRCHTIM unreachable _time value to reduce the risk of performance concerns because of excess TDU flows.
On an end node, instead of displaying the value configured, NO is displayed if UNRCHTIM=0 is configured and YES is displayed if a nonzero value is configured.

You can change the UNRCHTIM start option values with the MODIFY VTAMOPTS command while VTAM® is running. The unreachable_time value will be changed for the PORT statement and all GROUP statements that define connection networks in an XCA major node that do not override the start option value. The unreachable time for existing paths through connection networks to partner nodes that were determined to be unreachable before the start option value was modified will not be changed. When the existing unreachable time for a path expires, the new unreachable_time value will be used if the partner node through that path is determined to be still unreachable. The new partner_limit value will be used for all routes selected for new sessions and HPR path switches after the partner_limit value is changed.