On 08/23/2010 11:09 AM, Hiers, David wrote:
Packet8 is clearly big enough to write their own SIP stack for both the client and core devices. Don't know if they did, but I would not dismiss the possibility.
This is extremely unlikely, unless they inherited one via licensing from an acquisition. Developing a SIP stack is a surprisingly capital-intensive endeavour, at least, when it comes to working out interop issues and bugs, as well as natural race conditions arising from a literal interpretation of RFC 3261. All that testing and R&D is hard to afford. That's why the only good SIP stacks have been around for at least ten years (though, from this it does not follow that just because a SIP stack has been around for ten years means it's any good). Generally, the only ones with the resources to do it are major softswitch and/or SBC vendors, not service providers, because of the level of engineering and software development core competency required. For service providers development may be important, but is ultimately rather ancillary to their principal business functions, especially at the protocol stack level. Successful ITSPs like Packet8 are ultimately sales/marketing/fulfillment-dominated machines, first and foremost, above all else. Even then, much commercial gear today licenses the Radvision or Aricent stack. I know Cisco has their own, as does Siemens and did CopperCom, and certainly, Alcatel-Lucent. But there aren't that many of them, ultimately; well-worn commercially viable SIP stacks are a small family. Venturing outside of that family is where a lot of problems are found. -- Alex Balashov - Principal Evariste Systems LLC 1170 Peachtree Street 12th Floor, Suite 1200 Atlanta, GA 30309 Tel: +1-678-954-0670 Fax: +1-404-961-1892 Web: http://www.evaristesys.com/