Subject: RE: [SIP] SIP Info Method and IS-41 Cellular Signalling Protocol

From: James Yu <[email-masked]>
Date: Tue, 2 May 2000 07:50:34 -0500

Cellular intersystem operations can be separated into two types: transaction
based (e.g., for roaming support and handoff measurement) and call- or
service-related (for call setup during handoff and for intelligent network
call/service control).  Call-related operations certainly can be supported
by SIP.  Service control related operations probably are best supported by
MGCP/megaco if WIN/CAP are not to be used.  If WIN/CAP are used for
call/service control, sigtran would be the choice to carry the protocol.
Transaction based operations probably can just use sigtran to transport the
messages.  You can always add new parameters to IS-41 or GSM MAP to carry
SDP information. 

My earlier comment was about the handoff measurement part where no call set
up is needed. But I think you are looking at SIP or something else to
totally replace IS-41 (so as not to enhance IS-41 to support 3G)- so please
continue the search/investigation.

James  

> -----Original Message-----
> From: Giuseppe Ricagni [mailto:[email-masked]]
> Sent: Tuesday, May 02, 2000 6:39 AM
> To: James Yu
> Cc: 'James Kempf'; [email-masked]
> Subject: Re: [SIP] SIP Info Method and IS-41 Cellular Signalling
> Protocol
> 
> 
> James Yu wrote:
> 
> > James,
> >
> > Your question can be addressed by sigtran - SS7 transport 
> over IP.  There
> > are a few adaptation layers to choose including the newly 
> proposed SUA (for
> > SCCP users such as IS-41).
> >
> > James Yu
> >
> 
> Yes.
> 
> You definetly don' t need SIP if you only want to tunnel legacy
> signalling
> protocols over IP: SIGTRAN does the job much better (providing for
> endpoint
> redundancy, scalability, through the concept of multiple 
> streams within
> an
> association, encompassing a very efficient SACKs implementation that
> gives its
> best in case of retranmission of small chunks of information, 
> just like
> signaling messages, and.... really much more).
> 
> IMHO, you should tunnel in SIP (over SCTP, maybe) when you really add
> something
> to the base protocol, e.g by means of the SDP attributes SIP 
> can carry,
> that
> allow for the negotiation of much richer sessions.
> 
> The point is that this is actually the case, at least in many 3G
> cellular
> scenarios.
> 
> A completely new (SIP-based if SIP can provide all the necessary
> features)
> approach  could be also welcome in many cases.
> 
> Giuseppe
> 
> 
> 
> ----------------------------------------------------------
> Giuseppe RICAGNI
> System Architecture and Product Planning
> Broadband Networks
> Italtel
> via Reiss Romoli - C10
> 20019 Castelletto di Settimo Milanese (MILANO)
> ITALY
> 
> mailto:[email-masked]
> ----------------------------------------------------------
> 

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