The skype link you gave me, is good. Found a lot of interesting things there. I"ll check more about QoS of voip. 39% is not enough. That's from a web page that checks voip quality.
On Thu, Jun 12, 2008 at 10:34 PM, Geoff Shang <[EMAIL PROTECTED]> wrote: > sara fink wrote: > >> Someone knows if skype calls placed between 2 people in Israel, passes >> via skype server in europe? > > The short answer is not necessarily. > > 1. Skype calls do not go through a central server. A central server is > used to keep track of people's status etc. > > 2. If both ends of the call can make direct connections to each other > without going through NAT (i.e. if incoming connections can be made on a > particular port which I believe is picked at install time), the call is made > directly between both parties without being routed through any other hosts. > > 3. If it is not possible to make a direct connection between both parties, > a third host is used to relay traffic back and forth. > > Note that I'm not an expert on Skype and my understanding is mainly based on > my recollections of the contents of > http://www1.cs.columbia.edu/~salman/publications/skype1_4.pdf which is > admittedly a bit old now and which I read something like a year ago. You > can find a whole lot more of this kind of thing, some of it newer, at > http://www1.cs.columbia.edu/~salman/skype/ > >> Is there a standard for voip? What I mean is if there are limits, for >> download, upload, quality of service that produces a reliable >> conversation? > > Most of the time when people use the term "voip" nowadays, they are refering > to telephone-quality speech, generally using SIP, IAX2 or H323 at 8kHz > sampling. An uncompressed call using ULAW or ALAW encoding (which is what > is used natively on US and European phone systems respectively) will need > 64kbps for the audio plus overhead for the protocol. Codecs like Speex > (open) and G729 (patented) however attempt to carry such signals at only > 8kbps, and largely succeed. I've run G729 calls over a dialup connection, > though I don't recommend it. > > QOS is important. I don't know much about it myself, but I do know that if > you have the right QOS settings, you can happily do other stuff on your > connection and your voip trafic will get through quite nicely. If not, even > moderate network activity can be enough to scramble it. > > Wish I could be of more help. > > Geoff. > > ================================================================= > To unsubscribe, send mail to [EMAIL PROTECTED] with > the word "unsubscribe" in the message body, e.g., run the command > echo unsubscribe | mail [EMAIL PROTECTED] > > ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
