Hi,

The Request URI is a SIP concept, while the destination URI might be best 
described as a fictive invention of OpenSIPS configuration script. It 
represents the next-hop destination to which the request will be forwarded on 
the network and transport layer, as you correctly surmised, while the request 
URI is a logical destination. The destination URI supersedes the request URI, 
but if the destination URI is not set, the domain/port/transport attributes of 
the request URI are consumed to determine the forwarding destination.

An RURI is not the same thing as an Address of Record; an AoR refers to a 
logical URI entity in the location service (registrar) context. The purpose of 
a registrar is to map an AoR (such as sip:[email protected]) to one or 
more Contact URIs (e.g. sip:[email protected];user=phone), which indicate how 
to reach a given device on the network and transport layer.

Hopefully that helps!

-- Alex

> On Jul 30, 2024, at 9:26 PM, Mohamed OUALLA <[email protected]> 
> wrote:
> 
> Hello all,
> 
>   I have a technical question about the difference between Request URI and 
> Destination URI in SIP. In my understanding of SIP, the R-URI (Request URI) 
> is located in the start line of the SIP request and is also known as the 
> Address of Record (AoR). However, I am unclear about what the Destination URI 
> is for openSIPs. Is it the same as the Request URI, or is it related to an 
> added route header, or the destination address in the transport protocol, I 
> am not sure about it?
> 
>   Additionally, I have observed that when I change the $du pseudo variable in 
> OpenSIPS, it relays the request to the UAS without changing the R-URI (change 
> it with the sip uri I gave to $du pseudo variable). This behavior is the same 
> as using the t_relay() method, which also does not change the R-URI but sends 
> the request to the UAS. I guess that changes have been done only for the 
> destination address in the transport layer.
> 
>   Could someone please explain these observations and clarify the difference 
> between R-URI and Destination URI?
>   And the best way to route calls from UAC to UAS in simple VoIP call 
> components (Caller - SIP Proxy - Callee), actually I change the $ru, then I 
> forward() the request stateless or t_relay() stateful.
> 
> Thank you.
> _______________________________________________
> Users mailing list
> [email protected]
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-- 
Alex Balashov
Principal Consultant
Evariste Systems LLC
Web: https://evaristesys.com
Tel: +1-706-510-6800


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