[OpenSIPS-Devel] [OpenSIPS-Users] [RFC] NAT pinging

[Bogdan-Andrei Iancu]

Dan Pascu wrote:
> On Thursday 11 December 2008, Bogdan-Andrei Iancu wrote:
>   
>> Hi,
>>
>> I was evaluating an implementation for NAT pinging also via TCP
>> connection, but I just diging in the current pinging "logic" I found
>> some issues that needs to be sorted out first.
>>
>> B) PATH extension
>>
>> First of all if PATH is used and simply UDP ping is used, nathelper
>> pings the source of the REGISTER (where it came from).
>> Question: does this make sense? as anyhow the INVITEs will be sent to
>> the top PATH uri....
>>     
>
> In the nat_traversal module the border proxy (the one that receives the 
> REGISTER directly from the phone) will do the pinging, so it doesn't 
> matter if you use the path extension or not. This will not only avoid the 
> need to have code that handles the path extension case in a particular 
> way, but it also avoids unnecessary traffic along the proxies in the 
> path. Only the border proxy will send pings to the device directly.
>   
This approach seams logic to me also. I is absurd to have a complex 
scenario where the NAT ping is generated by some line-2 proxies.

As NAT is detectable only by the boarder elements and it is relevant 
only for this boarder elements, it should be handled by this elements only.

So, IMHO, NAT ping should not be affected at all by PATH - this 
extensions should be used only by registrar part.

Regards,
Bogdan