[Asterisk-Users] Should I choose DSL @ 1.5 or a full T1?

[Nir Simionovich]

Marcelo Pacheco wrote:

>SDSL has symmetrical speeds and full duplex communications.
>Of the widely deployed lan/wan technologies, the only one I know of that is 
>half-duplex is 802.11{b,g}.
>
802.11b/g are standards used in wireless (Wi-Fi) connections, there is 
no relation to the symetrics or
asymetrics of the actual physical line.

>The only technical difference between a T1 and SDSL is how it's physically 
>delivered to the customer, what usually happens is that a T1 is not oversold, 
>while an SDSL is oversold anywhere from 8:1 to 3:1.
>  
>
That is correct in the genereal idea, however, as xDSL technologies are 
switched technologies, unlike
cable (DOCSIS) technologies, the fact that you are overloaded 8:1 or 3:1 
will not really matter. As long
as your equipment supports QoS correctly, you shouldn't have a problem.

>ADSL is full duplex as well, if you don't know how to do QOS then it will feel 
>like it's half duplex, but it's not. I have 1000/320 ADSL that I can use full 
>bandwidth both ways.
>  
>
ADSL appears to be half-duplex only due to the fact that most ISP's 
"misconfigure" the modems and routers.
As a rule of thumb, the modem/router can be re-configured to utilize 
both channels to the fullest, but again, this
must rely on the fact that your ISP's equipment supports QoS at the 
switch level correctly.

Nir S

>Marcelo Pacheco
>
>Em Seg 13 Jun 2005 20:54, Damon Estep escreveu:
>  
>
>>You are aware that DSL (even SDSL) is half duplex and a T1 is full
>>duplex, right?
>>
>>1.5m sdsl can only do 768 sustained duplex, or 1.5 out 0 in, or 0 out
>>1.5 in. a T1 will do 1.5 in and 1.5 out sustained.
>>
>>This is due to a separate transmit and receive path on a t1 and a shared
>>path on sdsl.
>>
>>The s in sdsl means symmetrical, not duplex, that is that the signaling
>>rate is the same in either direction, but still half duplex.
>>
>>For VoIP a t1 is worth double what a 1.5 sdsl is because of the duplex
>>nature of the traffic, unlike most internet that is download-centric.
>>
>>-----Original Message-----
>>From: asterisk-users-bounces at lists.digium.com
>>[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Wiley
>>Siler
>>Sent: Monday, June 13, 2005 9:43 AM
>>To: Asterisk Users Mailing List - Non-Commercial Discussion
>>Subject: RE: [Asterisk-Users] Should I choose DSL @ 1.5 or a full T1?
>>
>>Speakeasy SDSL Is 1.5 Megs, is business class (so you get an SLA) and
>>only costs around $100 per month.
>>
>>W
>>
>>-----Original Message-----
>>From: asterisk-users-bounces at lists.digium.com
>>[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Robert
>>Goodyear
>>Sent: Friday, June 10, 2005 7:02 PM
>>To: Asterisk Users Mailing List - Non-Commercial Discussion
>>Subject: Re: [Asterisk-Users] Should I choose DSL @ 1.5 or a full T1?
>>
>>On Jun 10, 2005, at 6:38 PM, Michael Welter wrote:
>>    
>>
>>>Barton Fisher wrote:
>>>      
>>>
>>>>I'm looking to expand my bandwidth for my Asterisk PBX.  Why should I
>>>>
>>>>choose a T1 over DSL for my asterisk server?  I found someone
>>>>offering T1's for $290 a month + Loops or 3 Meg for $561 a month +
>>>>Loops.  Is this a good deal?
>>>> Thanks
>>>> Bart
>>>>---------------------------------------------------------------------
>>>>-
>>>>--
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>>>>
>>>Where are you located?  What CLEC gives you a T-1 for $290?
>>>      
>>>
>>FWIW I provisioned a PRI and a DS-1 for $300 each. Don't know if I'm
>>getting a break for having a voice and a data circuit broken out from
>>one fiber drop, but that's what I'm paying here in Orange County. Also,
>>I had a business cable modem before, which was *allegedly* not shared
>>for business customers (suspicious) and the throughput was a roller
>>coaster, as was the latency. The DS-1 cleared all that up.
>>
>>/rg
>>
>>Robert Goodyear
>>Brand Up LLC
>>http://www.brand-up.com
>>
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