[Serusers] UAS binding

[Daniel-Constantin Mierla]

On 04/14/05 05:10, Jack Damn wrote:

>Hi,
>
>I have a problem with registering with a UAS when using SER as a stateful proxy.
>The UAS stores the UAC IP address in it's binding list.
>This IP address was obtained by the Contact header field.
>
>Now if the UAS receive a call and needs to contact my UAC, an INVITE is sent
>directly to the UAC IP address instead of sending it to the proxy for relaying.
>
>What is the normal behavior of a UAS when receiving a REGISTER that is coming
>from a proxy server ? Sould it save the proxy IP address in it's 
>bindings table ?
>
If the UAS does the registrar functionality, then it must save the 
address from the Contact header. But you will get in troubles if the 
client is behind the NAT -- the UAS will be unable to detect NAT-ed 
clients. Storing only the proxy IP will be useless if the proxy does not 
store the contact address of the client. Storing both, the UAS can use 
the proxy as an outbound relay, but must use the contact address in the 
SIP request.

>
>
>Another question:
>Is it acceptable per RFC for a UAS to rewrite the SIP VIA headers and
>concatenate them
>on a single, separated by commas ?
>Don't ask me the reason for this, but I have noticed a UAS doing just
>that and I need to know
>if this is just wrong or acceptable.
>  
>
Yes, it can concatenate same headers in one separated by commas. The RFC 
allow both forms, so there should be no interoperability issue.

Daniel

>Thanks,
>
>Jack
>
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>  
>