[*] Latency on VoIP

[Bill Reid]

LES.NET (1996) INC. wrote:

> 
> So I would assume, that having an asterisk box on either end,
> similarly equiped, would add about 33 milliseconds to the overall
> latency
> 
> pstn -> ulaw -> g729(+27/27ms) -> internet(+50?/77ms) -> g729 -> 
> ulaw(+6/86ms) -> pstn

On the otherhand if the end device is an IP phone or adaptor which is
doing the g729 you may be looking at a much higher latency. Have you
seen any specs on translation time for various adaptors or phones?

For interest here is my times (Pentium III 450):

         g723   gsm  ulaw  alaw  g726 adpcm  slin lpc10  g729 speex  ilbc
  g723     -     -     -     -     -     -     -     -     -     -     -
   gsm     -     -     4     4    12     4     3    17    47     -    70
  ulaw     -    10     -     1    10     2     1    15    45     -    68
  alaw     -    10     1     -    10     2     1    15    45     -    68
  g726     -    17     9     9     -     9     8    22    52     -    75
adpcm     -    10     2     2    10     -     1    15    45     -    68
  slin     -     9     1     1     9     1     -    14    44     -    67
lpc10     -    19    11    11    19    11    10     -    54     -    77
  g729     -    18    10    10    18    10     9    23     -     -    76
speex     -     -     -     -     -     -     -     -     -     -     -
  ilbc     -    22    14    14    22    14    13    27    57     -     -

-- Bill