Re: [sipcore] Types of Call

salini,

I'm not certain of the context in which you are asking this question.
In general I think such things are better discussed on 
sip-implementors@lists.cs.columbia.edu. So if you want to have an 
extended discussion I ask you to go there. But I'll give you the short 
version of my opinion:

In practical/real-life we don't have a clear way to indicate this prior 
to answering the call. After answering, it gets handled informally 
in-band. In some cases I suppose it is inferred based on indicated 
identity of the caller.

SIP provides some mechanisms for this, but whether they are useful in 
practice is debatable. The Priority header allows the caller to indicate 
his opinion of the priority of the call. But the callee may choose not 
to believe this because of possibility for abuse. Even if it is 
believed, there is no guarantee that it will be acted on at the callee 
end of the call, or how.

There is also 
http://datatracker.ietf.org/doc/draft-ietf-salud-alert-info-urns/ which 
specifies how to use Alert-Info to cause differing sorts of alerting, 
that can be used to alert differently due to call priority.

Again, if you want to discuss this further, please do it on 
sip-implementors, unless you have a specific issue to make about a 
specific core sip capability.

	Thanks,
	Paul

On 5/3/12 11:44 AM, salini singh wrote:
> Hi,
>
> How do we distinguish URGENT,NON_URGENT,NORMAL,EMERGENCY calls in our
> day to day practical/real-life?
>
> Regards
> -salini
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