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

[Geoff Devine]

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