On 03/06/2011 01:18 PM, curriegrad2004 wrote:
And relativity comes into play too. Not unless you travel pretty fast. :-) Also you do need to realize that the packets sent via UDP isn't guaranteed to be in order as the fax machine expects the data to be sent in order, not out of order. That's the beauty of packet switched networks. You will also see a small number of packets arrive twice for UDP over the internet, presumably due to router bugs.
Out of order packets are not, in themselves, a problem. A jitter buffer will reorder them, if they are not excessively delayed (and the jitter buffer is not of a broken design). The real issue is excessive jitter in the packet delivery times, which is functionally equivalent to packet loss - packets have to be dropped if they arrive too late for the real time deadline of the analogue channel.
On Sat, Mar 5, 2011 at 7:29 PM, Steve Underwood<steveu@coppice.org> wrote:
On 03/06/2011 11:21 AM, envelopes envelopes wrote:
Why is PCMU codec not reliable?
Unsynchronised clocks, and packet loss.
Steve Steve