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Does end-user applications can interact directly with MN-CSE ? [message #1742640]

Tue, 06 September 2016 05:58

Eclipse User

Hi,

A little bit of context, in order to see if i have a correct understanding of OM2M:
- a MN-CSE is a gateway (previously a GSCL ?) that acts as a proxy to interact with the underlying sensors and actuators. So it's local to where those sensors and actuators are deployed.
- a IN-CSE is a server (previsouly a NSCL ?) that would be typically deployed in the cloud. Of course, IN-CSE and MN-CSE interact with each other.

Now, say for example that a MN-CSE gathers several sensor data and one application want to retrieve it and display them within some dashboards.
Does it mandatory for my application to interact with the IN-CSE ? The IN-CSE will re-target the different request from my application to the MN-CSE.
Or could my application interact directly with the MN-CSE ? And so avoid the extra-communications implied in the previous case (due to retargeting requests).

Thanks!

Re: Does end-user applications can interact directly with MN-CSE ? [message #1742854 is a reply to message #1742640]

Thu, 08 September 2016 04:57

Eclipse User

Hi Laurent,

I think it not mandatory that your application must interact with the IN-CSE so that the IN-CSE then can retarget your request to the corresponding MN-CSE. In case your application know the destination address of this MN-CSE in advanced then you guys can interact directly. That's why you can find in OM2M configuration that there are different addresses for IN-CSE and MN-CSE and if you send request directly to MN-CSE, you can see in the console that this request is not pass through via IN-CSE. But the direct communication happens just in case your application know the address of MN-CSE in advanced and I think you can do this only in small scale application with only some devices located in MN-CSE. In large scale application, it's not possible and nessesary to remember all addresses of your devices, instead your IN-CSE will do this job and you can retrieve information from your application via IN-CSE.

These above are just my idea and hope this can help you somehow

Regards,
Son

Re: Does end-user applications can interact directly with MN-CSE ? [message #1742873 is a reply to message #1742854]

Thu, 08 September 2016 07:11

Eclipse User

Hi Son,

Thanks for your answer. I agree with you, an application that directly interact with a MN-CSE is rather a local application. By the way, I'm wondering if MN-CSE could retarget requests (to an other MN- ? I guess no.

One additionnal question regarding the following sentence:
Quote:

In large scale application, it's not possible and nessesary to remember all addresses of your devices, instead your IN-CSE will do this job and you can retrieve information from your application via IN-CSE.

Did you mean the address of all MN-CSE ? And basically, it's more simple for an application to interact with one entry point (the IN-CSE) that will redirect your request to the different MN-CSE ?

Thanks!

Laurent.

Re: Does end-user applications can interact directly with MN-CSE ? [message #1742878 is a reply to message #1742873]

Thu, 08 September 2016 07:59

Eclipse User

Hi Laurent,

I think the retargeting requests can not be done with MN-CSE, it should be done with IN-CSE because at the beginning when the network is set up, the IN-CSE will be the one that cover all of the information of other MN-CSEs which registered to that IN-CSE. Therefore only IN-CSE have enough information of other MN-CSEs and use that information for the retarging purpose.

For the second question, devices that I mean here are those which connected into the gateway MN-CSE. Let assume that we have a situation like two light: light1 and light2 connected to MN-CSE, MN-CSE registers to IN-CSE. Therefore, IN-CSE also have information of the light devices. And if you want to retrieve some information or execute something with the lights, instead of sending directly request to each light by using their address, you can send to IN-CSE and IN-CSE will redirect your request to the corresponding light, you dont need to remember all of the addresses of each light.

Regards,
Son

Re: Does end-user applications can interact directly with MN-CSE ? [message #1742890 is a reply to message #1742878]

Thu, 08 September 2016 08:37

Eclipse User

Thanks for the detailed response Son Smile

!

Basically, if I understood correctly your first paragraph, it means that OM2M relies on a star topology with IN-CSE as the center of the star and the various MN-CSE as the edges.

For the second paragraph, from your use case where L1 and L2 (light 1, light 2) are connected to a MN-CSE. Since L1 and L2 are registered to it, it would be much simpler for an application to interact directly with the MN-CSE ? Since it hosts the resources to interact with them.
I agree that in a large scale systems with hundred of MN-CSE it could be quite complicated for applications to handle this. But in a smart home use-case, that's simpler.

By the way, how applications discover the different sensors and actuators and know how to interact with them ?

Thanks again Wink

!

Laurent.

Re: Does end-user applications can interact directly with MN-CSE ? [message #1742905 is a reply to message #1742890]

Thu, 08 September 2016 09:38

Eclipse User

Laurent Lemke wrote on Thu, 08 September 2016 12:37

By the way, how applications discover the different sensors and actuators and know how to interact with them ?

Sorry Laurent, I dont really get what you meant here?

Son

Re: Does end-user applications can interact directly with MN-CSE ? [message #1742929 is a reply to message #1742905]

Thu, 08 September 2016 11:38

Eclipse User

Perhaps it is a terminology problem, let me explain it with through your example.

1/ L1 and L2 are connected to a MN-CSE.
Correct me if I am wrong, but it means that both have created some REST resources in MN-CSE
For example:
/mn-cse/applications/lamp1/DESCRIPTOR
/mn-cse/applications/lamp1/DATA
...
same for L2 (replace the above URI containing lamp1 with lamp2)

2/ I assume that the IN-CSE is aware of L1 and L2 connected to MN-CSE with the corresponding resources

3/ Now, a client application that has some business logic want to turn-off every lamps automatically after midnight for example (that's not very smart... but well !).

How the client application will be aware that they are 2 lamps ? How it will be aware which URI he must use to turn off each light ?

I guess the client application will perform a request to the IN-CSE to know that, but what type of response he will receive ?

Laurent.

Re: Does end-user applications can interact directly with MN-CSE ? [message #1743001 is a reply to message #1742929]

Fri, 09 September 2016 05:57

Eclipse User

I am not sure if I understand you correctly but I think one way that your client application can be aware of the Lamps is using the discovery functionality defined in oneM2M by sending a GET request and the response will return you list of your deployed application, in this case is your lamp1 and lamp2. More information you can have a look on this Application Developer Guide here, it has an example similar to your case. But I think if we build a specific application and standing on a user side, here is the client application, you have to know in advanced which application you have here, it means you know in advanced that you have two Lamp applications. The other rest such as which URI is used for turning lamp off,....is what the progmammer define

I dont know if I undertand you correctly but hope that help you somehow Smile

Son

Re: Does end-user applications can interact directly with MN-CSE ? [message #1743021 is a reply to message #1743001]

Fri, 09 September 2016 10:07

Eclipse User

Great, I understand how it works. The link that you provided to the Application Developer Guide was very helpful.

However I have some other questions, but i will open an other thread to discuss about it.

Thanks a lot Son.

Best regards,

Laurent.

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