said by DataRiker:Almost. I used to work on DSL. On our newest VDSL you are aggregated before the edge router with all of our xDSL at the co-location, and then sent via fiber to another co-location with backbone. ( really depends on your area )
But I'm not referring to that. I'm referring specifically to the customer circuit. DSL is dedicated in that aspect, and so is GFiber with dedicated GigE runs to each user. (In other words, point-to-point networks.)
It's of course possible for the access layer uplinks to be congested (happens all the time, in fact), but that is the same whether we're talking about DSL or GFiber. I suspect GFiber has ample capacity going to their access switches, so this isn't likely to be an issue, but the same can apply for properly-managed DSL.
said by DataRiker:xDSL customers had it worse. Almost all of our line cards were failing and ancient, which means we cram them full. Definitely way oversold before the edge.
I assume by "line card" you're referring to a DSLAM chassis as a whole.
DSLAM uplinks being congested happens, but that's an issue with poor network management.
said by DataRiker:This myth really came about because xDSL was never really oversold to the extent of cable simply because it under delivered by a wide margin.
It's not really a myth, it's just creative advertising. Telcos like to use it in their DSL vs. cable attack ads. It's technically true in that (as we've established) the DSL circuit is dedicated (a point-to-point connection) while a cable network is point-to-multipoint and hence shared between everyone on the node. They just conveniently forget to mention the access layer (i.e. the DSLAM) is still oversubscribed.
said by DataRiker:You definitely see wild shifts in speeds on xDSL these days with our setup.
Not all DSL setups are like this.
CenturyLink out here has the same "two tier" setup. Their GigE-fed ADSL2+/VDSL2 DSLAMs are never congested (they're oversubscribed, but reasonably), but customers still on T1 or DS3-fed DSLAMs aren't as lucky and there's tons of complaints in the CL forum.