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E2M - State Machine

E2M - State Machine

Mar 05, 2020

Document status

DRAFT

Document owner

Avinoam Bernstein

Owner Details

+972-54-2891166,   ab600d@intl.att.com

 

RAN States

E2M supports the following state for each RAN:

State

Description

State

Description

Null

No RAN in DB

Disconnected

Either the connection failed, E2T dies or E2T initialized

Connected

Remote RAN sends Setup Request  

Shutting-Down

Temporary state during Red Button (From Dashboard)

Shut-Down

Persistent state after Red Button (From Dashboard)

RAN Events

We have the following events which might change SM:

  1. Setup Request from RAN

  2. Connection failed from E2T

  3. E2T Initialized - E2T Restart (New E2T or existing)

  4. Red Button (From Dashboard)

  5. Keep Alive (KA) in E2M discover E2T isn't responding

 

RAN State Machine - States vs. Events

RM = Resource Management

States ==> 

Events

Null

Disconnected

Connected

Shutting-Down

Shut-Down

States ==> 

Events

Null

Disconnected

Connected

Shutting-Down

Shut-Down

Setup Request from RAN

Connected;

Update RM;

Send Setup Response;

Update RM;

Disconnect-

Connected; (See note below)

Update RM;

Send Setup Response; 

Ignore

Connected;

Update RM;

Send Setup Response;

SCTP Failure (Lost Connection)

Error

Error

Disconnect;

Update RM;

Shut-down

Error

E2 Initialize

 

Ignore

Update RM;

Disconnect-

 

 

Red Button

 

Shut-down

Shutting-Down;

Tear down connection to E2T

Error

 

KA discover E2T dies

 

Ignore

Disconnect;

Update RM;

 

 

Note 

Flow of Setup -

  • Assuming Success parsing the message (Else - Error)

  • Update DB - RAN Name, RAN ID, Data in the Setup Request payload (Functions), State = Connected, E2T Address - Assuming DB write succeed Else - Error)

  • If update RM is OK (Associate RAN to E2T Address) 

    • Send Setup Response.

    • If RMR failure - Error but don't Roll back

  • Else (RM Failure)

    • Can't send RAN any message (Even Setup Failure isn't possible)

    • Leave RAN as connected and associated to E2T Address

    • When RM will initialized and query E2M, it will distribute the RMR to all RIC.

 

In case Setup Request in Connected State - Update DB (it might be different), Update RM (it might be even different E2T in rare scenario), Return Setup Response.

 

Flow charts in the RAN State

State = Null (RAN doesn't exist in DB)

Null State
Null State

State = Connected

Connected State
Connected State

State = Disconnected

Disconnected State
Disconnected State

 

State = Shutting Down

Shutting Down State
Shutting Down State

State = Shut Down  

Shut Down State
Shut Down State