[Users] REGISTER processing

[Klaus Darilion]

Daniel-Constantin Mierla wrote:
> 
> 
> On 10/10/05 11:25, Klaus Darilion wrote:
> 
>> Just to to throw oil on the fire: ;-)
>>
>> If the SIP UA uses TCP, and the connection is reset, usually the port 
>> in the Contact URI changes. Thus, a new entry in the location table 
>> will be created.
> 
> this should not happen. The UA should register the contact address where 
> it listens. Same tcp connection is used generally just at transaction 
> level, then it is closed by server. Keeping the tcp connections open for 
> long time will overload the server.

it happens: SNOM 360

> Ideally, in this case, the UA unregisters the previous contact when it 
> detects that it will register another contact address. When the UA does 
> not follow some basic rules, it is hard to predict and handle all 
> situations that can occur.

I would be nice if a phone would do this, but I do not think TCP 
implementations are better than UDP implementations.

> TCP and NAT will not work in most of the cases, and when there is no 
> nat, the UA has no excuse to behave wrongly during registration.

If I would implement a SIP client using TCP the client would:
- open the TCP connection
- send keep alive (CRLF)
- if the connection is terminated by the proxy or there is a delivery 
failure the client would immediately reconnect to the proxy.

IMO a SIP proxy should be able to keep >thousand TCP sessions open

regards
klaus

> 
> Cheers,
> Daniel
> 
>>
>> This can be avoided using the call-id as identifier.
>>
>> regards
>> klaus
>>
> 
>