Just a hollow tube to allow fibre to blown in later. Given how many tubes were bundled together into the minitrench, it was amusing to see how they checked which was which ... one chap walked up the road with a trolley containing a generator and a compressor and some hose, squirted air into the stopcock for each house, and then walkie-talkied to his mate to label which tube corresponds to that house at the cabinet end.
About 4% of us genuinely have fibre. FTTP - fibre to the premises.
Andy
FTTC gets you 80 if you're lucky, and more likely a lot less if you aren't next to the cabinet.
Retail fibre gives you 330 if you want to pay for it (GPON). And it doesn't matter how far the cabinet is.
That's a pretty muffled quack.
Andy
That doesn't apply to VM FTTC, though, as the coax distribution from the cabinet maintains its full 750MHz (typically) bandwidth throughout the entire coax network so it doesn't matter where on that network you are connected.
Mmm. There is a length limit on coax though
Yes and no.
There is a distinct difference between a coax network and a length of coax.
True, signals will be attenuated along the length of the coax, as with any other type of transmission line, particularly at the higher frequencies but, at intervals along the route, amplifiers restore the level and pre-equalise the levels for feeding the next section so, within limits, levels across the band are controlled throughout the length of the netork.
Also, the quality of the network is defined in a British Standard which forms part of the cable operator's licence terms.
Thus the signals fed to any subscriber on the network will conform to tightly defined limits which ensure that all subscribers receive the same level of service.
That is something that BT's copper network cannot do.
Virgin can't either. Although they have tight control over the signal levels there is the slight problem of contention. They only have a limited bandwidth available and its shared with all the subs on a segment. So you may get 330 Mb/s some of the time you may not get it if there are a few heavy users on your segment.
This is why virgin were traffic shaping to reduce the throughput of heavy users and leave some for others.
I don't know what traffic shaping they currently do.
BT suffers the same but the contention is in the links to the ISP not the access network like virgins. This means that different ISPs may have different connections and suffer from different levels of contention depending on what they pay for.
Mine for instance doesn't appear to have any contention as I can max out the link to the DSLAM whenever I try.
Well ours is around 350 metres IIRC but they are only in urban and suburban areas so you aren't likely to be "that" far from a cabinet we can get 350 meg odd here, if we want it, but its hardly worth bothering with the 220 we do get is fine for our needs the rest of the net seems it needs to catch up first;!...
Don't think they do now least not on the service we have, its fine:)
On a speed test its usually reporting over 200 Meg anytime.
Apart from re-segmenting the network so that fewer and fewer subscribers are on any individual segment, improments in DOCSIS enable a number of downstream signal (equivalent to DTV muxes) to be bonded together, thus they can continually offer higher and higher speeds as the technology improves.
I originally worked on commisioning a nrew network based on
600 home nodes, whereas 2,400 home nodes was the norm in the cable environment. This made resegmentation much easier to perform in the headend. I would imagine that, where demand exists, some of those older 2,400 home nodes have been split at street level to provide more flexibility.However, it is 11 years since I retired and it is a rapidly developing situation, so I have no idea exactly what goes on these days although I'm familiar with the basic principles.
Strange - it only seems a very short while ago that we were rolling out our initial 600bps broadband product in competition with 56kbs dial-up!
====snip====
Typo? ITYM 600Kbps broadband service. :-)
I *well* remember the time when NTL used the 'harmonisation' of the
128Kbps service to 150Kbps (quarter the speed of the 600Kbps which had formerly been 512Kbps) to squeeze a disproportionate (exhorbitant!) 3 quid increase over the 15 quid a month I'd formerly been paying.To be fair, it was only a 2.4% increase on a cost per Kbps speed basis but as far as I was concerned, they could stick their poxy 22Kbps speed "upgrade" where the sun don't shine and let me keep that 3 quid in my own pocket. Mind you, during the past 15 years or so, that same basic 150Kbps service has now morphed via several free speed upgrades into an 85Mbps service (only a paltry 5Mbps upload speed though) for just under 35 quid a month.
It has to be said that a price increase over a 15 year period that must be less than inflation for a 64 fold speed increase is a pretty good deal compared to the more typical customer experience of "Service Industries" in general.
It could. Line powered ADSL repeaters every 2km would have gootten everyone up to speed.
But the point is that copper twoisted pair and coax are the same. At distance the signals are so atteneuated that bandwith foes down withiout repeaters.
Most virgin is fibre to the cab and coax to the premnises. No repeaters
Coax is just a bit better up to say a km
Oops! Yes, 600kbps.
We were Bell Cable Media at the time (later Cable & Wieless Communications) and didn't offer a lower speed than 600kbps
I've never had the need for blisteringly fast upload speeds and I doubt that the average user does, either.
However, the reason for the lower upload speed is embedded in history when CATV first started and upload requirements were usuaally limited to STB and supervisory data comms.
Attainable bandwidths were also low - 300MHz in the mid 70s, increasing to 450MHz by the mid/late 80s, then 550 - 600MHz in the early 90s. The older networks were upgraded for the ionitial digital roll-out, when a figure of 750MHz was chosen for most networks.
By far the lion's share of this bandwidth was always for the downstream channels, the return path initially being 5 -
30MHz, increasing later to 50MHz and then 65MHz.When I was redesigning the RF distribution network for the Vintage Wireless Museum, I wanted a decent Band I/III diplex filter, which I managed to scrounge from VM.
As it came out of a large box of identical used 65/85MHz filters, I surmised that the return path had again been increased, probably up to 85MHz, meaning that the FM band was no longer carried.
How widespread such changes have been, I have no idea. Bearing in mind the large number of original cable operators there were intially, all with their own design ideas and choice of equipment manufacturer, uprading the networks on a national scale must be quite a tall order!
I'm now on what was originally Diamond Cable and, although I've worked on their broadband routers in the past, I've never had any contact with the RF side of their network, so know niothing about it but I've run some speed tests in the last few minutes and getting about 85Mbps download and just over
12Mbps upload.
!!!
The average subscriber drop cable is rarely likely to exceed a tenth of that!
Given that the signals leave the cabinet with a forward tilt, they won't be far off level across the band at the end.
That is much more than 'just a bit better' than God knows how many km of twisted pair.
er no. twisted pair from am FTTC cabinet is a lot less than a km gemeraly
Dont compare apples and oranges. The issue is whether or nmot FTTC
+twisted pair is better or worse than FTTC + coax.
I think it's you who has got his fruit confused - the post I replied to specifically referred to "Line powered ADSL repeaters every 2km".
No mention of FTTC and twisted pair
I ssaid that because someone hads said that teh coax network was better beacuse it had repeaters every few KM
I pointed out that that was not restricteted to coax and lartre, taht tha was not how virgins cable system works anyway.
Ultimately Virgin and B=T are bnoth mainly FTTC with dedicated VDSL over copper pair to the home, or shared DOCSIS over coax to the home.
DOCSIS, being shared, can be a lot slower than its raw speed suggests. VDSL is typically slower as the attenuation of twisted pair us higher than coax.
Both carriers offer FTTH at an exhorbitant cost where its not implemented at street cabinet level and the promise of more reasonable prices where it is.
BT will sell you a 100mbps internet connection for £400 a month. Over copper based ethernet.
As more and more people are using NAS boxes and may want to remotely access files or are storing things in the Cloud, upload speed is becoming more important. Especially useful for remote backup.
SteveW
And for uploading to youtube, that takes me quite a time when I need to do it. wish I could get a bit more speed for uploading.
Just how much stuff are you uploading to youtube that speeds of 5 - 10Mbps (the range of speeds being discussed) aren't good enough for you?
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