[Nice] a Farsight 2 nice transmitter, a git repo and various related thougths

Kai.Vehmanen at nokia.com Kai.Vehmanen at nokia.com
Wed Apr 30 04:25:44 PDT 2008


On 30 April 2008,  Olivier Crête wrote:
>Why is the state-changed signal per-component and not 
>per-stream? Should I care about the component state? I 
>currently wait until all components reached one state before 
>reporting it upwards, it that good?
>Also, I guess the whole stream should be failed if one 
>component fails..

this is another design choice made for old-jingle compatibility.
In old-jingle, one could start sending media immediately after 
connectivity was established over some candidate-pair. Reporting 
the states on per-component basis allows this mode of operation,
as well as others. So basicly we move the decision whether to send 
immediately, or whether to wait for a) all components of a stream, 
b) all streams, c) something else ...  onto the client -> library 
allows different usage models.

But I'm open for changing this. For instance making the signals
per-stream should be ok. There might be a small delay in starting
to send media (you have to wait for other components as well), but
OTOH, this is somewhat questionable optimization to start with as at 
that point you don't yet know whether connectivity can be established 
for the other components of a stream. The per-component signals are 
definitely a hassle for most clients, as they need to track the
state of their streams based on component signals (see nice/docs/design.txt
and the considerations for SIP clients).

Of course one option is to emit both per-component and per-stream

>Is there any reason to export ICE restart instead of just 
>starting a new stream?

Basicly with a restart, all state, _except_ the currently selected
pairs, are flushed. Thus you can reestablish connectivity (possible
over alternate routes), but without a break to media flow. We could
live without explicit nice_restart(), but having it supported 
in the library is convenient for the client (transparent handover
from the old selected-pairs to the newly found succesfully validated
candidate pairs).

first.surname at nokia.com (Kai Vehmanen)

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