[VOIPSEC] 4G Issue Map: signaling complexity - more

[Paul E. Jones]

Henry,

Have you ever looked at the SIP call flows required to support a call center
that has a proxy, an IVR, perhaps some other app servers, a queuing system,
and an agent?

It isn't "in the endpoint" (and cannot be, unless you want to build a very
small call center) and it isn't pretty. :-)

Paul

> -----Original Message-----
> From: Henry Sinnreich [mailto:hsinnrei at adobe.com]
> Sent: Thursday, August 24, 2006 8:34 PM
> To: Geoff Devine; Paul E. Jones; Brian Rosen; bill at flanagan-consulting.com
> Cc: Voipsec at voipsa.org
> Subject: RE: [VOIPSEC] 4G Issue Map: signaling complexity - more
> 
> Geoff Divine writes:
> 
> > I don´t see that the fully distributed call processing model
> > is workable in the general case.
> 
> This is an interesting point, since the most useful telephony applications
> can be implemented with SIP call control in the endpoints:
> - IVR
> - Auto-attendant
> - Receptionist workstation
> - Contact center agent workstation.
> So even for core telephony, all this maze of servers is not required.
> 
> What do you think?
> 
> Henry
> 
> -----Original Message-----
> From: Geoff Devine [mailto:gdevine at cedarpointcom.com]
> Sent: Thursday, August 24, 2006 6:25 PM
> To: Henry Sinnreich; Paul E. Jones; Brian Rosen; bill at flanagan-
> consulting.com
> Cc: Voipsec at voipsa.org
> Subject: RE: [VOIPSEC] 4G Issue Map: signaling complexity - more
> 
> Henry Sinnreich writes:
> > Such complexity is better placed in the endpoints, the only
> > ones that understand the application and that can be
> > developed in a controlled environment.
> 
> Right.  ...and what that means is any time you need to add a feature, you
> need to extend the protocol. When you extend the protocol, you need to
> ensure interoperability with potentially dozens of different client
> implementations and potentially dozens of different software revisions of
> each implementation.  Go look at what TISPAN or the PacketCable
> Residential SIP Telephony Spec (after the IPR review period expires next
> month) have done.  Unless you vendor lock on one client implementation, it
> will be wildly difficult to ever make the network stable.  The cell phone
> service providers can limit the damage by controlling the number of
> implementations and testing the heck out of everything.  They´ve also
> adopted a model where as many features as possible are done by the core
> network.  I don´t see that the fully distributed call processing model is
> workable in the general case.
> 
> Geoff
> 
>