Data transmission and reconnections in HDP

["José Antonio Santos Cadenas" <jcaden@libresoft.es>]

Hi all,

I start this thread to discuss the alternatives to move the data from the 
application to the l2cap socket in HDP. Till now we have the following 
alternatives (please, add more if we missed something)

Reconnections options:

 Option 1: Implicit reconnections: The application is not concern about the 
disconnections or reconnections of the data channel until it is deleted.

	We prefer this option because fixes more with a manager philosophy. A 
20601 manager sould not perceive temporal disconnections because this way can 
hold it state if it perceives a disconnection, next time it reconnects it will 
need to exchange again apdus for association.

 Option 2: Reconnections by the application. The applications are notified when 
a data channel is disconnected and should perform a reconnection before using 
it again.

Data transmission options:

 Option 1: Fd_passing the l2cap socket of the data channel to the client. The 
problem with this is that some data can be lost by d-bus if the channel is 
disconnected. (We have to check how fd-passing works).

 Option 2: Fd_passing a pipe and HDP will write the data in the l2cap data 
chanel socket. The problem with this is that we need 2 pipes for each data 
channel, but no data will be lost because HDP controls the data flow with the 
sockets and resend data not correctly sent.

	We think that the easier way for implicit reconnections is option 2. 
Because the application can always write on the socket it have (the pipe). 
Once written, the HDP layer tries to write it in the l2cap socket, if it 
fails, perform a reconnection operation over the data channel.

 Option 3: Transmiting the data by d-bus. We think that this option is bad for 
d-bus, because of the overload of the system bus.

 Option 4: Other IPC alternatives (more alternative here?)

Regards.