Re: IP Dslams

[Brandon Martin <lists.nanog () monmotha net>]

On 1/1/19 7:19 AM, Nick Edwards wrote:
> @Carl:  ADSL2 dslams would no doubt be cheaper than VDSL for retirement 
> village, and as a retirement village, residents must be 65+, therefor, 
> they wont have high bandwidth needs, based on their other much older 
> properties, their residents use between 2 and 15GB a month, with an 
> average of 5GB, so VDSL -if not the same cost as ADSL2 dslams, would be 
> a waste, and from my experience ADSL2 is more stable over distances, 
> where the furthest villas are 800 meters away from comms room.

If you're wanting to buy used gear, ADSL2+ DSLAMs are indeed probably 
cheaper, but you might have trouble finding native IP/Ethernet ones.  A 
lot of the older stuff predating the VDSL era was very ATM-centric.

I'm not sure anyone's still really making ADSL2+-only DSLAMs, so I'm not 
sure a 1:1 cost comparison is even possible on new gear.

Note that most VDSL/VSDL2 DSLAMs do support ADSL2/ADSL2+ fallback, so 
you're not stuck with VDSL if you do have a problematic link, and you've 
got a bit more future-proofing.  You can also get G.FAST DSLAMs with 
VDSL and ADSL2 fallback if you wanted to really have some future-proofing.

800m is probably pushing it for G.FAST, but VDSL2 should run on that 
just fine even on crummy old voice-grade copper.  Depending on how it's 
bundled, you might not be able to use every pair in a cable for VDSL2, 
but if you're putting POTS on a separate pair, that means half your 
pairs right there are not running DSL at all.  Again, with most VDSL 
DSLAMs, you've got the option of ADSL2 fallback if you do need it on the 
long-distance links.

ADSL2 does have the advantage that you can (probably) run POTS+DSL on 
the same pair if you need to.  I'm not sure that's possible with VDSL, 
but I'd love someone to prove me wrong.
--
Brandon Martin