what is difference between tnt-id and sessionId or the relation between them ?

[atef00]

I know that tnt-id is the primary identifier and automatically generated by Adobe target but what is the relation 
on the server side what is the usage of TNT id can I send the tnt-id in the header by myself and what are the consequences of doing that? 
why tnt-id if we will provide a session Id value  tnt-id takes it's value 

https://{clientCode}.tt.omtrdc.net/rest/v1/delivery?client={clientCode}&sessionId=hello

the tnt-id in response will be  hello

  "id": {

        "tntId": "hello.37_0"

    },
and what is 37_0 ?? 

[abu_shafi · Accepted solution]

(sessionId Is required) -Session Id that should be generated and maintained by you. Make sure this value does not get changed within a session. if user is inactive for 30 min generate a new one. 

**The session is active for 30 minutes on the server side. Therefore, you shouldn’t use a different SessionId for a particular tntId/thirdPartyId within 30 minutes of the last request made with the tntId/thirdPartyId. Otherwise, changes to the profile could be inconsistent and unpredictable.**

**Using the same Session ID with multiple tntIds/thirdPartyIds may cause unpredictable changes to the profiles identified by the tntId/thirdPartyIDs.**

tntId/thirdPartyIDs is non-required fields You can ignore this

tnta this value is important if you want to use A4T to work. you have to capture this value and pass it via the analytics call

https://shafi.com.au/how-to/adobe-target/adobe-target-api-server-side-implementation/ 

[Kishore_Reddy]

Hey @atef00 

This could be helpful with additional technical info: https://experienceleague.adobe.com/docs/id-service/using/implementation/ecid-a4t-target.html?lang=en