[Sip-implementors] Use case for P-Early-Media header (RFC 5009)

[isshed]

Hi All,

SIP defines the "P-Early-Media" header to control the forward/backward
early media. Could any of you guys help me understand the use case? I
am not able to get the use case.

Why servers have policy to block/control the early media communication?
Thanks in advance!

Thanks,
-Isshed

[Brett Tate]

Post by isshed
SIP defines the "P-Early-Media" header to control the forward/backward
early media. Could any of you guys help me understand the use case?
I am not able to get the use case.
Why servers have policy to block/control the early media communication?

Hi,

See sections 1 and 4. The unstated use case is billing. Some devices
want to communicate using early media to avoid billing situation by not
answering the call or reducing the time within an answered call; some
carriers want to prevent/control such behavior.

-brett

[isshed]

Thank you Brett for the reply.
I am still not able to connect to any example. It would be great if
you can provide an example.

Thanks!!

Post by Brett Tate

Post by isshed
SIP defines the "P-Early-Media" header to control the forward/backward
early media. Could any of you guys help me understand the use case?
I am not able to get the use case.
Why servers have policy to block/control the early media communication?

Hi,
See sections 1 and 4. The unstated use case is billing. Some devices
want to communicate using early media to avoid billing situation by not
answering the call or reducing the time within an answered call; some
carriers want to prevent/control such behavior.
-brett

[CALME, Jim (Jim)** CTR **]

The P-Early-Media header is used in signaling the "authorization" of early media. Network nodes will often grant and enforce the authorization.
The following are some general examples.
A SIP UE to UE call will typically not exchange media until after answer, therefore early media is not authorized - P-Early-Media:inactive.
A SIP UE call that interworks to the PSTN will have backward media authorized to allow call progress tones from the PSTN to be passed to the UE - P-Early-Media:sendonly.
Calls that require user interaction (e.g., prompt and collection) prior to the call being delivered to the end user (and prior to the SIP dialog being confirmed) will authorize both-way media - P-Early-Media:sendrecv.

Jim

-----Original Message-----
From: sip-implementors-bounces at lists.cs.columbia.edu [mailto:sip-implementors-bounces at lists.cs.columbia.edu] On Behalf Of isshed
Sent: Tuesday, October 07, 2014 2:30 PM
To: Brett Tate
Cc: sip-implementors
Subject: Re: [Sip-implementors] Use case for P-Early-Media header (RFC 5009)

Thank you Brett for the reply.
I am still not able to connect to any example. It would be great if you can provide an example.

Thanks!!

Post by Brett Tate

Post by isshed
SIP defines the "P-Early-Media" header to control the
forward/backward early media. Could any of you guys help me understand the use case?
I am not able to get the use case.
Why servers have policy to block/control the early media communication?

Hi,
See sections 1 and 4. The unstated use case is billing. Some devices
want to communicate using early media to avoid billing situation by
not answering the call or reducing the time within an answered call;
some carriers want to prevent/control such behavior.
-brett