[Asterisk-Users] MTU and Voice Delay (latency??)

[Rich Adamson]

Geoff Manning wrote:
> As an update and back to the original response from Rich re: duplexing
> 
> The topology looks like this:
> 
> 	8 Cisco IP Phones
> 		|
> 		|
> 	3COM 226 PWR-Plus
> 		|
> 		|
> 	Speedtouch 610s
> 		|
> 		|
> 	  SHDSL Line
> 
> When I used to have the ADSL modem plugged into port 1 of the 3COM switch,
> the port would auto-sense to 100 Full, with Flow Control Enabled.
> 
> With the SDSL modem plugged into port 1 it auto-senses to 100 Full but with
> Flow Control Disabled.
> 
> Here are the results of playing with the setting between the 3COM and
> Speedtouch:
> 
> Speedtouch set to 100Full  -  3COM set to Auto
> 3COM port configures at 100Half; Flow Control Enabled
> 
> Speedtouch set to 100Half  -  3COM set to Auto
> 3COM port configures at 100Half; Flow Control Enabled
> 
> Speedtouch set to 10Full  -  3COM set to Auto
> 3COM port configures at 10Half; Flow Control Enabled
> 
> Speedtouch set to 10Half  -  3COM set to Auto
> 3COM port configures at 10Half; Flow Control Enabled
> 
> -------------
> 
> 3COM set to 100Full  -  Speedtouch set to Auto
> Speedtouch configures at 100Half; 3COM Flow Control Disabled
> 
> 3COM set to 100Half  -  Speedtouch set to Auto
> Speedtouch configures at 100Half; 3COM Flow Control Enabled
> 
> 3COM set to 10Full  -  Speedtouch set to Auto
> Speedtouch configures at 10Half; 3COM Flow Control Disabled
> 
> 3COM set to 10Half  -  Speedtouch set to Auto
> Speedtouch configures at 10Half; 3COM Flow Control Enabled*
> 
> * (This test is inconclusive since I crashed the web interface of the modem.
> The modem is located on the other side of the Atlantic so I'll need to wait
> until they power cycle it in the AM.)
> 
> So if I leave it as is (both set to Auto) then Flow Control is Disabled on
> the 3COM switch
> 
> If I configure it so the Flow Control is Enabled then the 3COM defaults to
> Half Duplex.

Is there a way for you to use ethereal to "see" what's coming through
the dsl circuit?

What happens if you set the 3com AND Speedtouch to "full duplex"?

Flow control is not necessary for what you're doing; disable it if you can.