sbiddle:

 

It's very easy to guarantee voice quality over xDSL - just deploy EUBA with a CIR component such as EUBA192. The sole purpose of this product originally was going to be for Telecom's PSTN replacement project.

 

Deploying EUBA with a CIR component does nothing to protect from intermittent packet loss due to electrical artefacts on the line causing micro-outage style interference, and hence does not 'guarantee' voice quality. We're talking about two different things. You're talking about a guarantee that the necessary amount of bandwidth is available from the ISP to the PoP DSLAM via the Chorus backbone. I'm talking about the inherent nature of DSL's susceptibility to external influences on the line that the end user is unable to address.

sbiddle:

 

Fibre also doesn't guarantee voice quality unless you're on a HSNS connection where both ends of the connection are fully managed and queued or you're using the CIR component of a UFB connection and using appropriate 802.1p tagging and your voice service is with the internet provider as I can't imagine there will be any who will tag traffic from outside their own network.

 

I totally accept that UFB provides no additional guarantees for transit across the LFC network. The point I was making is that fibre is not susceptible to the myriad of electrical interference effects that DSL is and because of this it is, in the real world, far far more reliable than DSL for VoIP.