[Asterisk-Users] Asterisk Codecs [G.729]

[John Fraizer]

You need to decide if you're going to measure both sides of the call or not. 
  ITU standard is 64Kbits/s.  That is correct.  It is a standard DS0.  But, 
guess what.  That DS0 goes both directions so, "measured bandwidth per call" 
is 128Kbits/s using your logic.

Only "consumer" grade DSL/Cable bandwidth is asymmetric. These "wanna-be" 
connections and the accompanying garbage that the sales/marketing monkeys 
spew (that the general public laps up as accurate) have done nothing but 
cause confusion to people who don't work the network side of the industry.

[rent on]
(Besides that, it makes their peering ratio so lopsided that there is no way 
they're going to get any decent no-settlement bilateral peering and as such, 
the price of those connections is going to remain artificially high since 
the providers have to PURCHASE transit instead of simply peering.) [rant off]

When I order an OC3, it's 155Mb/s in BOTH DIRECTIONS.  The industry doesn't 
say "That's 310Mb/s of bandwidth" because the measure of circuit bandwidth 
is by maximum one-way FLOW.  You can (on paper) flow 155Mb/s in one 
direction on an OC3 (including encapsulation overhead).

So, if you want to use accepted telco + IP metrics for measuring the flow 
(and thus the bandwidth), you look at the GREATER OF THE IN/OUT flow and 
that is how much bandwidth is required.

ULAW = 83Kbits/s including encapsulation overhead.

John


wrote:
> Absolutely agree,
> 
> ITU standard is 64Kbits/sec.
> 
> VoIP traffic with U-law per channel is 83Kbits/sec.
> 
> VoIP traffic with U-law per call is 166Kbits/sec [measuring bandwidth per
> call]
> 
> ----- Original Message ----- 
> From: "Nicolas Bougues" <nbougues-listes at axialys.net>
> To: <asterisk-users at lists.digium.com>
> Sent: Wednesday, March 10, 2004 9:55 AM
> Subject: Re: [Asterisk-Users] Asterisk Codecs [G.729]
> 
> 
> 
>>On Wed, Mar 10, 2004 at 09:03:57AM -0800, <Unavailable ID> wrote:
>>
>>>Rich,
>>>
>>>In real world, using real tool, getting real number.  You don't expect
> 
> to
> 
>>>either talk only mode or listen only mode.  Per call must have Rx & Tx
> 
> for
> 
>>>inbound & outbound.
>>>
>>
>>[...]
>>
>>
>>>Engineering rate is per channel but to calculate the bandwidth
> 
> consumsion,
> 
>>>it must be in realtime full-duplex.
>>>
>>
>>Sure, but in the real world, IP trafic is mostly carried over full
>>duplex links (either serial or switched Ethernet), so you usually
>>consider the trafic in one direction only (provided it's symetrical).
>>
>>If I consider an E1 to be 2 Mbps (2 inbound, 2 outbound, really), and
>>Fast Ethernet to be 100 Mbps (again, 100+100 in full duplex), I shall
>>consider U-law to be 83 kbits/s, not 166.
>>
>>-- 
>>Nicolas Bougues
>>Axialys Interactive
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> 
> 
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