01-26-2012 12:00 PM
Hope this gets to the right place. This is my first entry, so please point me in the right direction if I've put this in the wrong place. I'm running Polycom Telepresence M100 through two bonded ADSL connections and it seems that there is no tollerance to packets arriving out of sequence. As soon as there are two seperate lines involved, the other end sees a 50% packet loss. If I disconnect one of the lines then everything works fine. I'm not an expert, so excuse the question if it's not phrased correctly, but is there no "Jitter Buffer" to prevent this.
03-12-2012 07:42 AM
In digital IP networks, the time for a data packet to get from one end to the other is not
tightly controlled, as it is in the public switched network. This delay can vary substantially
even from one packet to the next, so a VoIP system requires a function called a “jitter
buffer” to smooth out this data flow. When jitter buffers are too small, they can be
overloaded by a packet with greater than normal timing variation; when this happens
there will be a packet error, sounding just like a packet dropout (see above). The design of
a jitter buffer is a delicate tradeoff because jitter buffers add latency. Too small, and more
packet dropouts occur, while too large, and the latency is objectionable. The best
solution to this issue is to be sure that the network itself has been designed to minimize
jitter and latency, thus allowing a small jitter buffer.
Sr. Product Support Technician