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Keep Alive
Each Configurable time (100 500 Milliseconds currently) E2M sends broadcast KA Request to all living E2T Instances through the RMR.
Every E2T Instance which gets it, responds with KA Response.
If any E2T Instance doesn’t respond for a configurable time (400 1500 Milliseconds currently) - E2M “kills” it:
E2M asks the K8S to kill the E2T Instance.
E2M disassociate the RANs associated with this “dying” instance, signs them as disconnected and Updates the RM about the disassociation of the RANs and about the deletion of the dead E2T Instance.
There is some logic how to sync between parallel flows - Killing an E2T Instance parallel to E2 Initialize arrives. See below.
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E2M manages States that E2T Instance can be in the DB:
Active (normal state). Selector mechanism can choose it.
To be deleted - KA moves it to this state in DB the moment is understand it is dead. Selector mechanism can’t choose it. It is stay in stayed in this state until Routing manager success (in this case the entire entry is deleted) or failure, which is moved to the next stepE2T shutdown process completed.
In case E2T initialize arrives and this E2T is in “To be Deleted” state - Don’t do anything. E2T will send another E2T initialize in case no KA during 300 milliseconds after E2 Initialize.
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- The RM is informed on this Association between RAN and the E2T address
- But also if RM isn't accessible, E2M doesn't rollback nor sending Setup Failure to remote RAN - since the simple way to ask the E2T to send Setup Failure not through the normal MEID flow is quite complicated.
Dissociation RAN
There These are 3 the places where E2M dissociate RAN:
When a Lost Connection arrives from E2T
When existing E2T Instance restart and E2M receives E2T Initialize message
- When KA decides to kill an E2T Instance
- When Red Button tears down all RANs.
- In all these places - E2T address is cleared from the RAN(s) object(s), the RAN(s) removed from the list of RANs served in the E2T Object
- The RM is informed
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