hosted PBX/VOIP thru VPN?

Aaron Wolfe aawolfe at gmail.com
Wed Nov 12 07:39:19 PST 2008


On Tue, Nov 11, 2008 at 9:17 PM, Lorell Hathcock <lorell at hathcock.org>  
wrote:
> All:
>
>
>
> My customer wants to try to improve performance to his ATAs by  
> creating a
> VPN from his network to the VOIP provider's network through the  
> internet.
>
>
>
> I have to admit, the idea caught me flat footed.  At the outset, it  
> seems
> like we would want to do it just to improve security for end users.  
> However,
> my customer wants it because he thinks it will improve performance  
> (i.e.
> voice quality).  We are suffering from poor VOIP quality due to the  
> Sprint /
> Cogent depeering and subsequent squirming by our vendors.
>
>
>
> The only reason I can think that VOIP thru a VPN would help is that
> *perhaps* routers in the middle on ASNs I have no control over *may*
> prioritize VPN traffic higher than regular traffic.  They opposite  
> could
> also be true.
>
>
>
> Specifically the ASNs in the middle are Level 3, Sprint and Time  
> Warner.
>
>
>
> Thoughts?  Should I try to dissuade him from this if performance is  
> his main
> motivator?
>

Your customer may have seen this article (or a similar one):

http://www.oreillynet.com/etel/blog/2006/03/strangely_ssl_vpns_can_help_vo.html

After reading it a year ago, I've found their discoveries to hold true
on my own (small) projects with voip.  In a nutshell:

"In every case, adding an SSL VPN to a VoIP call over a good broadband
network improved call quality. So in effect, wrapping a VoIP call in
SSL gives it more structure, kind of like the rind of good Brie. What
we had not counted on was the huge difference between what VoIP
requires (64Kbps) and a typical broadband connection of 500Kbps or
more. Because the broadband connection was so fast, TCP was able to
repair the impairments without reducing voice quality. "

May or may not apply to your situation, but if bandwidth isn't scarce
then I wouldn't be surprised if your customer is correct, at very
least they are not crazy :)

Good luck
-Aaron

>
>
> Thanks!
>
>
>
> Sincerely,
>
>
>
> Lorell Hathcock
>
>
>
> OfficeConnect.net | 832-665-3400 (o) | 713-992-2343 (f) |
> lorell at OfficeConnect.net
>
>
>
> ocbannerjoomla





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