But the biggest concentration of news, in the short time since Ive been gone, has to do with making the RBOCs lock on the local loop irrelevant; in other words, driving voice competition that divorces the telcos entirely. Easiest to understand in this connection is cable, whose share of the residential broadband marketplace is booming. Lurking in the wings is fixed wireless, which transmits between neighborhood base stations and indoor or outdoor transceivers and also circumvents the telco. Thats all about physical access. Another step on the road to PSTN irrelevance is VOIP-carrier-to-VOIP-carrier interworking. "Cable operators want a call that starts at Comcast and goes to Coxall IP," says my SIP guru.If conversations can hop from one IP carrier to the next, and from an enterprises own IP PBX to IP carrier, without having to gateway out to a PSTN and back in again, we achieve VOIP end-to-end. The PSTN is cut out entirely. Thats why you now see many interop announcements between carriers, such as Level3, and CPE vendors, such as Nortel, Avaya and Cisco.Its also why theres more noise around a new class of beasts called session border controllers, which transcode between SIP, MGCP and H.323 VOIP protocols and variations thereof, and also negotiate problems of firewall transversal. Obstacles on this bypass road certainly exist. One is E911 (Enhanced 911) compliance: If you typed "911" in your instant-messaging window, how would anyone know where you actually were? And where would that message go? Since Internet telephony addresses are similarly placeless, mechanisms have to be employedand several arethat automatically route distress calls to the proper emergency response center. Click here to read about Siemens plan to launch a next-generation IP PBX. Another obstacle is presented by FBI rules that require federal wiretapping abilitya hard nut to crack in a stream of data packets. Yet another is assuring universal-service subsidies to less populated regions that present less economic incentive to network buildout. Finally, theres the problem of taking a traditional phone number and making it work like an IP address. Say your traditional phone number is on your business card, but most of your world can now reach your phone over IP. A protocol called ENUM, the result of work of the Internet Engineering Task Forces Telephone Number Mapping Working Group, deals with a standard way of converting that number into an IP address, so that VOIP networks can route calls independently of the routing tables and SS7 signaling used by telcos. ENUM is to work with domain name servers, in the same way that URLs get resolved down to physical addresses. So here, after a few months absence, are the very broad strokes of the VOIP landscape on the service provider side. Columns to follow should take up some of these developments and players in turn. Check out eWEEK.coms VOIP & Telephony Center at http://voip.eweek.com for the latest news, views and analysis on voice over IP and telephony.