Re: [Anima-signaling] GRASP relaying

[Brian E Carpenter <[e-mail]>]

On 03/01/2016 15:05, Brian E Carpenter wrote:

...
> 4. A bit to my surprise, the session ID is also pretty much useless
> in discovery (M_DISCOVERY and M_RESPONSE messages), except for loop
> prevention. The reason for this is quite complex. In the prototype,
> things work as follows:
> 
> An ASA calls discover(objective, timeout). Here's
> what discover does (simplified):
> 
> if the objective is already in the discovery cache:
>     return cached locators
> else:
>     send M_DISCOVER message on each interface
>     launch a listener thread for each interface*
>     wait (at most) until timeout
>     if the objective is now in the discovery cache:
>         return cached locators
>     else:
>         return nothing
> 
> Each separate listener thread waits for any M_RESPONSE
> replies, and adds them to the cache.
> 
> *(yes, I know, in theory one thread can listen to replies from
> all interfaces, but I tested it and it didn't work)
> 
> The bottom line is that although the M_RESPONSEs will carry
> the same Session ID, it is not used in any way.

I need to correct this. I found an error in the way I handled
listening for M_RESPONSE messages: in fact they all end up
arriving on the same socket for a given interface, and the code
*does* need to demultiplex them using the Session ID.

However this doesn't change anything in the GRASP protocol.

    Brian