Enlist, Unenlist, Start and Stop BizTalk subscriber State | Uses and their difference with an example in BizTalk Server

Today I will explain very confusing BizTalk subscriber states i.e. enlist, unenlist, start and stop so lets begin with following details-

Required:

1. Atleast one receive location (Publisher). 
2. One or more orchestration (both Publisher and subscriber).
3. Also atleast one send port (Subscriber).

Enlist state: Enlist is prestate before Start subscriber state either in send port or in orchestration that means when we enlist a send port or orchestration then message publish at receive location then it firstly check subscriber (either send port or orchestration) and this case it is available in BizTalk MessageBoxDB but message will be not move further process. Its only available in suspended state with resumable condition. In short when we enlist send port or orchestration then it make availability in MessageBoxDB.

Start state: If send port or orchestration is in Start state then when message received by receive location port then message is ready to move further process without going to suspend state.

Unenlist State: In this subscribe state neither message in suspend nor it will be move for further business process because when a message published at receive location firstly it check subscriber and this case no subscriber available in MessageBoxDb.

When send port or orchestration is in unenlist state and we have published message by receive location then we receive following error-

"The published message could not be routed because no subscribers were found. This error occurs if the subscribing orchestration or send port has not been enlisted, or if some of the message properties necessary for subscription evaluation have not been promoted. Please use the Biztalk Administration console to troubleshoot this failure."

Stop State: Last but not least in this stop state when send port or orchestration is in started then only we can do in stopped state or if send port or orchestration unenlisted state then available option is enlist after click it automatically moved in stopped state that means in this stop state case a subscriber is available in MessageBoxDb but if message published by receive location then message will be move for further process. Lets my orchestration is start state but few of send port are in stopped state then my message will be go to one by one send port if it stop state then message will be not process and its in suspended state and if it in start state then message will processed.

Explain with Example:

Let us my receive location name is RL_GetFile_Test_BizTalkLive, Orchestration name is orchTest_BizTalkLive and send port name is SP_Test_BizTalkLIve.

Publisher : RL_GetFile_Test_BizTalkLive
Subscriber: orchTest_BizTalkLive and SP_Test_BizTalkLIve

RL_GetFile_Test_BizTalkLive:  Enable or Disable
orchTest_BizTalkLive and SP_Test_BizTalkLIve:  Start, Stop, Enlist and Unlisted

When a message published by using my receive location(RL_GetFile_Test_BizTalkLive) then it need at least one subscriber available in MessageBoxDb in form of either in my orchestration(orchTest_BizTalkLive) or in my send port(SP_Test_BizTalkLIve) to further process without any error. Suppose my  orchTest_BizTalkLive and SP_Test_BizTalkLIve in stopped state then message will be suspended state and available in BizTalk Administrator Console in resumable condition and if unenlisted state then message available with not resumable condition.

Note:
If a subscriber is in Started state then we can either Stop or Unenlist.
If a subscriber is in Stopped state then we can either Start or Unenlist.
If a subscriber is in Unenlisted state then we can either Start or Enlist.

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