Subject: [SIP] Carrying Q.BICC as an Mime-type in SIP

From: Chip Sharp <[email-masked]>
Date: Mon, 10 Apr 2000 08:27:08 -0400

ITU (SG11) is currently defining a variant of ISUP that is being called 
"Bearer Independent Call Control" (BICC).  I'm sure many of you are aware 
of this.

They have completed work for Q.BICC to handle Narrowband ISDN services over 
ATM (this is now numbered Q.1901) and they are now beginning work on IP and 
other networks.

It seems that networks using SIP will have to interwork with these networks 
as well as the current PSTN that uses ISUP.

Could (or should) this be included in the SIP-T draft?  Would it be its own 
type or could/should it be included as a value for the version or spec field?

Chip
http://www.netaid.org
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Chip Sharp                 CTO Consulting Engineering
Cisco Systems
Reality - Love it or Leave it.			
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From: "Mark Watson" <[email-masked]>
Date: Wed, 26 Apr 2000 17:43:51 +0100

There will defintely be a need to consider interworking between SIP(-T) and
BICC, but whether this should be done by this group or ITU-T SG11, I am not
so sure about.

I do not think we need to carry BICC inside SIP-T though. BICC is basically
ISUP with extensions for controlling an IP or ATM bearer. SIP-T can already
control IP/ATM bearers using SDP so it wouldn't make sense to carry the
extra BICC stuff as well. It should instead be interworked to the equivalent
SIP mechanism for setting up the bearer.

I expect there will be discussions on this kind of issue at the next SG11
meeting on BICC (1-5 May).

Regards,

Mark Watson
Nortel Networks, UK

> ----------
> From: 	Chip Sharp
> Sent: 	Monday, April 10, 2000 1:27 pm
> To: 	[email-masked]
> Subject: 	[SIP] Carrying Q.BICC as an Mime-type in SIP
>

---

From: "Rosen, Brian" <[email-masked]>
Date: Wed, 26 Apr 2000 14:36:30 -0400

I don't agree.  One of the interesting cases of SIP-T, for which the whole
notion
of the ISUP MIME type was invented was to allow ISUP SIP ISUP connections.
Allowing BICC SIP BICC should be allowed.  Of course, the BNC-ID, the ?ADM?
message, etc introduced in Q.BICC could just go through the MIME encap.
 
Of course, the cool thing would be to eventually get the media to flow
through all
three networks as one IP end-to-end stream!
 
I'll note that we plan to have the BNC-ID be an item specifiable in SDP for
other reasons
soon.
 
Brian

-----Original Message-----
From: Mark Watson [mailto:[email-masked]]
Sent: Wednesday, April 26, 2000 12:44 PM
To: [email-masked]; 'Chip Sharp'
Subject: RE: [SIP] Carrying Q.BICC as an Mime-type in SIP

Regards, 

Mark Watson 
Nortel Networks, UK 

	---------- 
From:   Chip Sharp 

	ITU (SG11) is currently defining a variant of ISUP that is being
called 
"Bearer Independent Call Control" (BICC).  I'm sure many of you are aware 
of this. 

	They have completed work for Q.BICC to handle Narrowband ISDN
services over 
ATM (this is now numbered Q.1901) and they are now beginning work on IP and 
other networks. 

	It seems that networks using SIP will have to interwork with these
networks 
as well as the current PSTN that uses ISUP. 

	Could (or should) this be included in the SIP-T draft?  Would it be
its own 
type or could/should it be included as a value for the version or spec
field? 

	Chip 
http://www.netaid.org <http://www.netaid.org>  

	_______________________________________________ 
SIP mailing list 
[email-masked] 
http://lists.bell-labs.com/mailman/listinfo/sip
<http://lists.bell-labs.com/mailman/listinfo/sip>

---

From: Chip Sharp <[email-masked]>
Date: Wed, 26 Apr 2000 14:57:20 -0400

At 05:43 PM 4/26/00 +0100, Mark Watson wrote:

>There will defintely be a need to consider interworking between SIP(-T) 
>and BICC, but whether this should be done by this group or ITU-T SG11, I 
>am not so sure about.
>
>I do not think we need to carry BICC inside SIP-T though. BICC is 
>basically ISUP with extensions for controlling an IP or ATM bearer. SIP-T 
>can already control IP/ATM bearers using SDP so it wouldn't make sense to 
>carry the extra BICC stuff as well. It should instead be interworked to 
>the equivalent SIP mechanism for setting up the bearer.

 From the few discussions I've been involved in and the documents I've 
read, SG11 is very adamant that Bearer-Independent Call Control isn't 
supposed to carry "bearer-dependent" information.  Of course, they have 
relented a little in order to carry some addressing info 
(BIWF-address).  Also, BICC has not been extended to control IP bearers 
yet.  CS2 is still in the requirements stage and the current draft of the 
BICC CS2 requirements includes support of IP bearers as a requirement.

Given that, you may be right that it doesn't necessarily make sense to 
carry BICC in SIP-T, but it is something that should be kept in mind since 
we don't know exactly what SG11 will come up with in the end.

Perhaps what we need is a way to carry SDP in BICC. :-)

>meeting on BICC (1-5 May).

I've decided not to fly to Melbourne for the week and go to the CALEA JEM 
instead.  Have fun.

>Regards,
>
>Mark Watson
>Nortel Networks, UK
>----------  From:   Chip Sharp  Sent:   Monday, April 10, 2000 1:27 
>pm  To:     [email-masked]  Subject:        [SIP] Carrying Q.BICC 
>as an Mime-type in SIP
>
>called  "Bearer Independent Call Control" (BICC).  I'm sure many of you 
>are aware  of this.
>
>They have completed work for Q.BICC to handle Narrowband ISDN services 
>over  ATM (this is now numbered Q.1901) and they are now beginning work on 
>IP and  other networks.
>
>networks  as well as the current PSTN that uses ISUP.
>
>Could (or should) this be included in the SIP-T draft?  Would it be its 
>own  type or could/should it be included as a value for the version or 
>spec field?
>
>Chip  <http://www.netaid.org>http://www.netaid.org 
>Chip Sharp                 CTO Consulting Engineering  Cisco 
>Systems  Reality - Love it or Leave 
>it. 
>_______________________________________________  SIP mailing 
>list  [email-masked] 
><http://lists.bell-labs.com/mailman/listinfo/sip>http://lists.bell-labs.com/mailman/listinfo/sip 
>

-------------------------------------------------------------------
Chip Sharp                 CTO Consulting Engineering
Cisco Systems
Reality - Love it or Leave it.	
http://www.netaid.org		
-------------------------------------------------------------------

---

From: "Mark Watson" <[email-masked]>
Date: Thu, 27 Apr 2000 11:43:44 +0100

If we have CS(A) --bicc ---CS(B)---sip --- CS(C)---bicc---CS(D)

where 'CS' is 'Call Server', for want of a better term, then there are two
cases:

(i) with the bearer path routed directly between Gateways controlled by
CS(A) and CS(D), and

(ii) with further 'packet-to-packet' gateways contolled by CS(B) and CS(C)
i.e. there are three 'domains' which are physically interworked at both the
call and bearer layer.

There is some doubt as to whether (i) will be possible at all - this depends
on how the support of IP in BICC is defined over the next few months. If it
is possible, I think that it should involve maping the bearer control
mechanism in BICC to the equivalent in SIP (SDP) so that the call can still
work if it terminates on a pure SIP agent. If you don't include this
compatibility, it's not SIP at all. You mention that SDP will be including
an equivalent to BNC-ID (I believe it's called EECID ?). As I understand it
this would allow you to do exactly what I'm suggesting.

If you do this mapping, then you've removed from the BICC information
everything which makes it BICC and not ISUP, so you're not carrying BICC
inside SIP at all.

In case (ii), the three domains are completely independent from each other
when it comes to setup of the bearer connection. Again, the only information
from BICC left to carry over the SIP domain is the ISUP part.

If we were to carry the BICC APM parameter, which contains the Bearer
related information, over SIP, we would be inventing a new way of carrying
out bearer setup on a SIP call - an alternative to SDP. I do not think we
should do this as it would be non-backwards-compatible.

Regards,

Mark Watson
Nortel Networks

> ----------
> From: 	Rosen, Brian
> Sent: 	Wednesday, April 26, 2000 7:36 pm
> To: 	Watson, Mark [MAIFP:EP11-M:EXCH]; [email-masked]; 'Chip
> Sharp'
> I'll note that we plan to have the BNC-ID be an item specifiable in SDP
> for other reasons
> soon.
>  
> Brian
> 
> 	There will defintely be a need to consider interworking between
> SIP(-T) and BICC, but whether this should be done by this group or ITU-T
> SG11, I am not so sure about.
> 
> 	I expect there will be discussions on this kind of issue at the next
> SG11 meeting on BICC (1-5 May). 
> 
> 	Regards, 
> 
> 	Mark Watson 
> 	Nortel Networks, UK 
> 
> 		---------- 
> 	From:   Chip Sharp