Corvus
Flaming Tards Since 2003
Premium,VIP
join:2003-11-26
| reply to Sean
Re: 3web - Sick of "unlimited download" claims yet
said by Sean  :Obviously both a DSLAM and a HFC node have available bandwidth link bottlenecks (though they aren't really, since often times theres enough bandwidth there), but AFAIK a HFC node has that extra bottleneck put in by the DOCSIS standard, that a DSLAM doesn't have. Yes, DSLAM has this same bottleneck: the max capacity of the cards used PLUS distance limitations...
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The Republicans are the party that says government doesn't work and then gets elected and proves it.--P. J. O'Rourke |
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Sean
join:2004-01-23
Ottawa
 ·Bell Sympatico
| reply to Corvus
said by Corvus :said by Sean :there's no "bandwidth" bottleneck at a DSLAM. Provided there's enough bandwidth on the main network, every user at a DSLAM can download full throttle. There is a bottleneck possible on DSL and it's at the DSLAM: Available bandwidth is limited by the capacity of installed fiber links. It's the same for a HFC node: available bandwidth is limited by the capacity of installed fiber. That's true; but as far as I know, a HFC node has it's own bandwidth bottleneck regardless of the available fibre links, as is set by the DOCSIS standard it's using. Isn't that true?
Obviously both a DSLAM and a HFC node have available bandwidth link bottlenecks (though they aren't really, since often times theres enough bandwidth there), but AFAIK a HFC node has that extra bottleneck put in by the DOCSIS standard, that a DSLAM doesn't have. |
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Corvus
Flaming Tards Since 2003
Premium,VIP
join:2003-11-26
| reply to Sean
said by Sean :there's no "bandwidth" bottleneck at a DSLAM. Provided there's enough bandwidth on the main network, every user at a DSLAM can download full throttle. There is a bottleneck possible on DSL and it's at the DSLAM: Available bandwidth is limited by the capacity of installed fiber links.
It's the same for a HFC node: available bandwidth is limited by the capacity of installed fiber.
These two statements are true when:
1- The DSLAM has the appropriate number of slots for the number customers
2- The HFC node (serving group) has the appropriate number of customers vs capacity
Reasons why we barely see bottlenecks on DSLAM is because there's fewer DSLAMs than HFC nodes (fiber is centralized to only few points in cities, cutting cost of fiber since it's way shorter but more far of customers end) and because most DSL users only get speeds between 2.5 and 3.5 Mbps, reducing the load/stress on DSLAM.
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The Republicans are the party that says government doesn't work and then gets elected and proves it.--P. J. O'Rourke |
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Sean
join:2004-01-23
Ottawa
·Bell Sympatico
1 edit | reply to NeoThe1
The only bottleneck a DSLAM has is the number of slots... there's no "bandwidth" bottleneck at a DSLAM. Provided there's enough bandwidth on the main network, every user at a DSLAM can download full throttle.
On DOCSIS, even if there is enough bandwidth on the main network, the node won't allow every user to download full throttle, as each node has it's own bandwidth bottleneck (DOCSIS3 is supposed to make that a LOT bigger than it currently is, but we'll see). Since most cable co's oversubsribe on two levels (bandwidth, as well as hardware), it's makes the potential "problem" bigger.
NeoThe1: I'm on your side. My post was in reference to andyb, sorry. |
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