Dutch ISP Demos Symmetric 100Mbps DOCSIS3 159
Mark.JUK writes "CAI Harderwijk, a DOCSIS 3.0 based Cable Modem operator in the Netherlands, has apparently managed to achieve a world first by demonstrating symmetric broadband internet access speeds of 100Mbps. The tiny Dutch operator is home to just over 16000 customers and was already planning a switch onto Fibre-to-the-Home (FTTH) technology, although this may now be delayed. The test itself is important because cable operators are still, perhaps unfairly, seen by some as being inferior to fully fibre optic-based broadband services. In reality, cable operators are, for the most part, continuing to keep pace."
Re:So some Dutch people now have 100Mbps connectio (Score:4, Informative)
Re:Distance? (Score:5, Informative)
It's not DSL, it's cable, so using coax cables instead of telephone lines. I don't know what that means for speed vs. distance though. For your information: "CAI" is Dutch for "central antenna installation". Those cables have been laid to deliver TV signals.
Secondly "laying FTTH" of course is nice, but it's also mighty expensive and disruptive to break open all the streets and dig trenches to everyone's home. These CAI cables are there already, so why not continue to use them? Just like what DSL is basically doing with telephone lines.
When building new homes of course nowadays they should put an optical fibre in the trenches that they dig already for telephone, cable TV, water pipes, power lines, etc. Then it's a relative cheap upgrade. But for existing homes this is definitely the cheaper option.
Cable = 1GHz of bandwidth (Score:1, Informative)
One coax cable has a usable bandwidth of about 1GHz. All users connected to the same cable share this bandwidth. Depending on the signal-to-noise ratio, encodings, forward error correction, different effective channel capacities can be realized. In practice it's going to be about 7bits/s/Hz, so the total capacity of a coax cable is no more than 7Gbps, which of course isn't all available for internet access because people still want cable TV. At most 35 dedicated symmetric 100Mbps connections can be supplied by one coax cable, fewer if you consider technical limitations and split usage with cable TV. Hundreds of customers are typically connected to the same cable.
Re:Distance? (Score:3, Informative)
The main difference between DSL and DOCSIS cable is that DSL is your personal connection. No one is sharing it. DOCSIS cable line is shared between those on the same line, so if you have active warez people in your neighbourhood or someone hosting an active server of some kind, expect much lower speeds and higher latency then advertised.
Second difference, which has been largely negated lately is latency. DSL offers slightly lower latency by advantage of design.
Tradeoff is that DSL only uses one really shitty quality copper pair, that limits distance and maximum speed far more severely then cable's coaxial. This is exacerbated by the fact that many phone lines are from times before CAT3 home cabling, which is a realistic requirement to reach even ADSL2 level of speeds, causing end user speeds to be below 10mbps even over 24mbps ADSL2+ connection.
Re:burst (Score:3, Informative)
Err, not everyone lives in countries with no consumer rights.
I can go at 40-50mbit all day both directions and not a word from my ISP (capped by my inferior linksys router, actual line speed is 60mbit) - what they have realised around here is most people wont be going "balls-out" all day on their connection, there is simply a maximum for how much information any given pira.. err user can crave.
Inferior to fiber (Score:4, Informative)
The test itself is important because cable operators are still, perhaps unfairly, seen by some as being inferior to fully fibre optic-based broadband services
Of course cable *is* (technologically) inferior to fiber. There's no doubt about it. 100Mbps would be trivial on fiber, heck 1Gbps would be trivial on fiber. The only advantage of cable is that it's already there, whereas for FTTH the vast majority of households will have to wait for a long time until they are connected.
Re:Cable = 1GHz of bandwidth (Score:4, Informative)
Where I live, we have cable in a star topology, rather than ring/loop, and just in these 4 houses, there are 220 apartments. Yet I can still hit 5-6 MB/s during peak hours, on a 50Mb/s down connection, from a decent FTP like say Sunet.
Re:burst (Score:1, Informative)
If you are referring to bandwidth caps, I can assure you that most providers in the Netherlands (where the ISP in the article is located) have no such thing. Some have a 'fair use' policy, the rest are truly unlimited.
I'm on DSL and get the full 30 Mbps I pay for. No caps, no throttling, no nonsense.
Re:Distance? (Score:3, Informative)
Re:Distance? (Score:3, Informative)
You seem to be assuming that there's no congestion control on the cable. In practice, if 9 people are downloading and you try to get your email then they will all be throttled back a tiny bit, won't notice, and you'll think your connection is fine. Most cable ISPs (outside the USA) resegment if a part of their network is being congested.
Re:Distance? (Score:2, Informative)
The main difference between DSL and DOCSIS cable is that DSL is your personal connection. No one is sharing it. DOCSIS cable line is shared between those on the same line, so if you have active warez people in your neighbourhood or someone hosting an active server of some kind, expect much lower speeds and higher latency then advertised.
Second difference, which has been largely negated lately is latency. DSL offers slightly lower latency by advantage of design.
Tradeoff is that DSL only uses one really shitty quality copper pair, that limits distance and maximum speed far more severely then cable's coaxial. This is exacerbated by the fact that many phone lines are from times before CAT3 home cabling, which is a realistic requirement to reach even ADSL2 level of speeds, causing end user speeds to be below 10mbps even over 24mbps ADSL2+ connection.
This is VERY wrong.
#1. DSL is shared just like cable, just at a slightly different point. Several DSL customers connect to the same node and from there, they are given times slices. example. My brother has aDSL, he has ~20 people on his local node and he had an 80ms ping to his first hop. Yes, his ISP that is just down the road is an 80ms jump. If he had this dedicated connection you talked about, it would be impossible to have anything much more than 1ms to his ISP.
#2. even FTTH has local choke points. You don't connect directly to your ISP, you connect to a local node. Your local node is shared by many many people.
#3. Cable uses CDMA. You can have several people per channel talking at the same time. You share a local physical coax loop with a few of your immediate neighbors. This coax loop has a crap ton of bandwidth. You then connect from this coax loop to your local node, this node is shared by several loops.
The *only* difference between cable and other techs is that the connection between you and your node is shared, but your node to ISP is still fiber and has the same limitations of all the other techs.
My trace route to Chicago is about 700 miles long which is a 3ms ping at the speed of light in a vacuum. I get a 15-18ms pings to Chicago from my ISP , during peak hours I might add, and my ISP has over 2 million internet customers over that link.
Fixed IP addresses? (Score:5, Informative)
Otherwise, CAI Harderwijk now have a thoroughly modern infrastructure. For instance, they can remotely control the availability of their services to individual clients. This is as opposed to UPC (the only available cable ISP in and around Amsterdam), who still have to arrange their client connections locally and manually. The latter method has the added disadvantage that a small percentage of cable customers will always enjoy services for which they do not pay -- something that is impossible to avoid due to the scale and the administration involved. CAI Harderwijk does not have this problem; an advantage that they can now pass on to their ISP customers.
That's how it is everywhere (Score:5, Informative)
Cable is basically always star with regards to multiple houses. Reason is that cable companies need to be able to charge per house, connect and disconnect services per house. If it was looped through all places, well then they'd lose any ability to do that.
What you also discover is that for a lot of reasons, cable Internet being one of them, they've built out the fiber part of their network quite far. The cable network isn't all coax and hasn't been forever. It is called a HFC, Hybrid Fiber Coax, network because that is what it is. So you find that because of that, they can and do segment it down pretty far. Yes you'll share with other places, but probably somewhere in the 32-128 realm, which is the same you get with a FTTH PON connection.
Also with DOCSIS 3 they can separate users out even more. DOCSIS 3 allows for multiple channels to be used for data (that is how it gets its speed). Well they can have even more channels than a single person gets. So each user gets, say, 4 channels (152mbits) on their modem. However they have a total of 16 channels for a segment. They then stagger what channels users are on so there's less sharing going on.
Don't get me wrong, FTTH has the capacity to be faster in the long run, fiber optics just has more theoretical bandwidth because of that whole Shannon's Law thing. However cable can work very well, and does when providers want it to.
Re:Fibre good because of less obvious reasons (Score:1, Informative)
Re:Distance? (Score:1, Informative)
You totally missed the GP's point (although he didn't state it very clearly.)
With most DSL setups, if you do a tcpdump on the interface connected to your DSL modem, you only see your machine's traffic. With DOCSIS setups, you see all the traffic from your neighbors' machines, as well.
I think everyone here realizes that at some point upstream your traffic is aggregated with your neighbors' traffic.