Solution - Responder - PubSub Sporadically Missing Messages

Version 4

    Behavior

     

    Responder Explorer may not receive change updates on some clients after inactivity.  It may work on the same client for some time and then stop working again if the network has built-in redundancy.  Users will see no updates for calls or other events coming in and eventually will also see a message in Responder Explorer about missing PubSub traffic.

     

    Cause

     

    Responder uses Multicast PGM traffic to deliver the messages of a new update such as a call, incident, or other system changes.  These PGM packets sent through multicast are only sent once, and not requested or sent again if they are not recieved.  The Responder PubSub implementation requires zero packet loss of PGM traffic and checks for internal sequences to verify it is not missing anything.

     

    In a complex network that has built in redundancy, the routes through spanning trees are built on command and then torn down at set intervals of inactivity.  The building of routes may lead to packet loss as the route is generated in device memory.  Once the route is in place, traffic flows through correctly but Responder may lose an update in the building process.

     

    Solution

     

    If your users are seeing sporadic behavior of the Responder PubSub messages like the behavior above, we recommend you set the timeouts of the device route list to not expire.  Before removing the timeout, users can set the value to something very long to verify this may be the issue.  The steps to perform this will vary depending on what hardware is deployed and users will need to seek the manufacturer for the specific devices.  This will allow the route to always be in place, and in memory, to assist with constant flow of the PGM packets.

     

    Please contact Schneider Electric Customer Service if you have any questions or concerns.