[bradleyland]

> The authentication info is bigger than the call data required to set up a call.

That's not a counter-argument, it's a cop out. SSL negotiation uses more bandwidth than a vanilla HTTP GET request too, but sometimes a secure channel is more important than preserving bandwidth.

> Telcos with TDM or CDMA transmission have serious backwards compatibility problems.

More cop outs. In order to resolve problems, you have to make changes. You can't show up to the solutions meeting and proclaim that a problem can't be solved because "the old system doesn't work that way." Sometimes you must abandon the legacy systems to solve new problems.