On Sat, Jan 07, 2006 at 03:00:14PM +1300, Andrew Errington wrote: > In other news, I just discovered Gizmo. This is a similar thing to Skype, > but uses SIPphone and standard VOIP. It may be preferable to Skype for two > reasons. > > 1) Uses open, standard protocols > 2) Does not use excessive resources on your PC (apparently Skype uses your > PC as part of its own network for processing and call routing.)
SIP is a traditional client/server model - the SIP network operators need to keep enough big servers running all the time to carry the calls. However, just like the real Internet, you can route calls between different SIP networks - so you can think of them as being "just" ISPs. On the other hand, Skype uses central servers only for handling call origination, and everything after that is routed in a peer to peer fashion through multiple client machines. Therefore Skype can scale rapidly without the central servers being too critical - they're not handling the calls. Contrast HTTP to BitTorrent :-) Neither is perfect, neither is "correct". -jim
