Re: [dispatch] SIP and GSM/UMTS with OpenBTS

I don't necessarily think 3GPP is out of scope in that I think it's very
important that if IETF decides that we will be documenting or even defining
protocol elements to support OpenBTS, it needs to be clear why 3GPP Call
control/SIP specifications aren't being used.

In offline in discussions with the proponents, it's my understanding that
OpenBTS is being used in very specific environments where there is no full
MSC deployments (i.e., remote locations that have no deployed IMS
networks).  The intent isn't to replicate a full IMS system, but rather to
provide basic connectivity to the Internet and use SIP in a non-IMS context
to complete the calls.   So, I think more detail about this context would
be very helpful.

I think it would really help if there were some diagrams showing what IMS
protocols are being used.  My understanding is that current implementations
have various ways in which they are interworking the Radio Layer Call
Control messages to SIP messages.  I think the motivation is to improve
interop by defining a consistent "mapping" if you will.  It's not clear to
me how exactly registration is being handled - perhaps mapping some of the
Radio Layer mobility management messages.   My understanding is that there
can be no change to the existing messages from the cell phone to the BTS
for obvious reasons, so all the interworking needs to happen in the BTS.

Regards,
Mary.

On Wed, Feb 5, 2014 at 4:34 PM, Michael Hammer <michael.hammer@yaanatech.com
> wrote:

> Could we take debates about 3GPP off-line?
>
> Seems to be getting off-topic.
>
>
>
> *Michael Hammer*
>
> *Principal Engineer*
>
> *michael.hammer@yaanatech.com <michael.hammer@yaanatech.com>*
>
> *Mobile: *+1 408-202-9291
>
> 500 Yosemite Drive Suite 120
>
> Milpitas, CA 95035 USA
>
>
>
> *From:* dispatch [mailto:dispatch-bounces@ietf.org] *On Behalf Of *James
> Winterbottom
> *Sent:* Wednesday, February 05, 2014 5:33 PM
> *To:* Makaraju, Maridi Raju (Raju)
> *Cc:* dispatch@ietf.org
> *Subject:* Re: [dispatch] SIP and GSM/UMTS with OpenBTS
>
>
>
> Check out SLh.
>
> Check out SLg
>
>
>
> On 6 Feb 2014, at 9:31 am, Makaraju, Maridi Raju (Raju) <
> Raju.Makaraju@alcatel-lucent.com> wrote:
>
>
>
>
>
> DIAMETER is used to carry signalling information through out IMS.
>
> *[Raju] Which interface? and what kind of signaling? To the best of my
> knowledge, diameter is only used for "authentication, authorization, and
> accounting". The Rx diameter interface used between P-CSCF and PCRF is not
> really call processing related signaling but rather used for
> "authorization" of the media flow.*
>
>
>
> *-Raju*
>
>
>
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