Something for the geeks I found
 

Development of access networks.

In 2004 Comcast, an MSO in the USA, began to construct the CRAN (Converged Regional Access Network). This essentially is a Metronet (Metropolitan Area Network). Rather than the traditional idea of taking signals from a node in the CATV network, backhauling it along with many other nodes to a central hubsite or headend then converting it to IP on a CMTS and transporting it to a core network the idea of the CRAN was to take the High Speed Internet traffic and convert it to IP at the earliest feasible opportunity, then rather than having inflexible fibre backhaul from hubsites to use 10gigabit Ethernet and a full layer 3 network.

The advantages of this are clear. Communications between subscribers in local areas no longer need to be backhauled to a central point on core network and instead can be contained on the CRAN in that region. Also this allows for more targeted IP services such as IP Telephony and indeed Video on Demand over IP.

Comcast aren’t alone in doing this, last year (2005) Telewest announced a project to install routers in all of their hubsites, and ntl have been building a Metronet in all of their on-net areas, with the plan to eventually backhaul everything across this network.

These metronets and the introduction of IP deeper in to the network allow cableco’s to save on bandwidth by keeping more traffic local and provide ‘IP everything’. As analogue switch off happens the spectrum freed up by removing these channels will be soaked up by DOCSIS 3 cable modem traffic, VoIP and IPTV. At present television channels are delivered to subscribers usually via an ATM network, then they are delivered as a stream of MPEG2 frames. There is no real targeting possible apart from the traditional VoD method of directing an STB to tune to a channel, and it relies on cable network segmentation at the RF level to be sufficient to allow for all streams required in a node to be deliverable. If too many people in a local area want VoD at the same time something has to give and they can’t all have it! VoD over IPTV would be no more difficult to direct to an individual subscriber than the current streaming video seen across the internet at this time.

There’s also bandwidth to be saved for broadcast television as well. If no-one in a local area is watching QVC ZOMFG BUY ME +1 then why waste the bandwidth multicasting it there?

Eventually the cable operator’s aim will be to deliver all services, broadcast TV, Video on Demand, Voice over IP via a single converged DOCSIS 3 fat pipe. As RF is seen less as an impediment to delivering targeted services and purely as a transport network for IP services so cable companies can also increase the bandwidth offered on their high speed internet services, and with all services using the same ultra fat pipes statistical contention will allow MSOs to push the bandwidth they have harder while still achieving levels of service that satisfy most subscribers.

In addition as the Metronets become more developed and the RF network more broken down with fibre deeper into the networks the case for FTTP (Fibre to the Premises) [img]Download Failed (1)[/img]
becomes a more viable one and pushing the fibre those last few hundred feet less of an obstacle (indeed already the main impidement in most cases is the costs of CPE (Consumer Premises Equipment rather than the actual fibre runs which tend to be quite short now).

Cablecos aren’t the only ones following this model. BT’s 21CN is based around the exact same model, and a ‘broadband dial tone’ to every customer on an exchange is their long term aim, with all customers rather than using the traditional switched telephone network being migrated to an IP Metronet. All lines connected to ADSL waiting to be switched on and all calls over IP after hitting exchange. Some telephone lines are already on an MSAN (Multi Service Access Node) – a device which can offer both broadband ADSL and transports telephone calls digitally. Just as Cable companies are converging their access networks onto an ‘IP everything’ model so are BT, with backhaul being provided by MPLS / IP enabled networks.

So what kind of bandwidths can we expect from these services? In a lot of ways it doesn’t actually matter that much as everything we do will be using the same pipe, everything delivered over a broadband network. Sky’s the limit.

Re: Something for the geeks I found
 

but are ntl doing anything like this?

Re: Something for the geeks I found
 

"coming soon" ;)

Re: Something for the geeks I found
 

Aren't ntl specifically referred to in the doc?

---------- Post added at 21:45 ---------- Previous post was at 21:45 ----------

Re: Something for the geeks I found
 

Thanks for the info IG, :tu:

and there's everyone thinking that the service disruptions were just ntl trying to upset their customer base. :rolleyes:

Re: Something for the geeks I found
 

Nice article ig. The last mile however, as far as I can see still remains the same, so the bottleneck for broadbabd still exists to an extent of how much data can flow over those channels.

So its still a case of waiting for DOCSIS 3.0 to take advantage of the greater bandwidth available on the access network, right?

Why is it I feel that I've got my wires crossed :o:

Re: Something for the geeks I found
 

First I heard of ntl using docsis 3.

Slowcoach its a good thing to get service disruption during maintenance I agree as it means they doing something, problem is I have had just 1 in the last 15 months.

Re: Something for the geeks I found
 

Yes, I am normally happy when they disconnect me for a few hours, performance is always better after.
Last weeks maintenance resulted in 10meg round the clock for me although I could have done without disconnections off and on last night when I was trying to set up a Linux Web Server here, kept asking myself "is it me or is it ntl", nightmare. :confused:

---------- Post added at 16:58 ---------- Previous post was at 16:39 ----------

BT is in the process of digging up the pavement all down the main road to lay a new cable which goes to a giant CAB behind my house, the cable on the roll is bright yellow and about 2CM Diameter, give or take a bit.
What technology is this likely to be, simply a replacement for the original shot cable or could it be 21st Century stuff?

Re: Something for the geeks I found
 

I had an IOS upgrade which I initially thought was a reseg this was last week, I believe my ubr has had no previous outage causing maintenace since early 2005 before that. Yet they seem happy to just keep signing up new customers.

Right now I am downloading of a 100mbit german server at 50kB/sec a joke, 30 secs before I started I fxped to a friend on telewest at 800kB of the same server.

Re: Something for the geeks I found
 

Just because you have stayed where you are doesn't mean that other people haven't been resegmented off the card you're on. Remember that!

On another subject the author of that article is welcoming any feedback any geeks here might have on it, good or bad (so he says :) ).

---------- Post added at 21:25 ---------- Previous post was at 21:19 ----------

21CN is the evolution of the core network away from the traditional PSTN (Public Switched Telephone Network) and to an all-IP core network with soft-switches, literally software switches.

They've ordered a ton of kit from a lot of suppliers, I've had people from Siemens and Cisco ask me if I wanted to interview for a job helping to implement the thing.

Though was kinda necessary, BT were a bit late to catch onto this IP malarky so they're spending the dollars now, but it's great and will actually (although a lot of people will hate this) make the BT core one of the most advanced in the world.

BT are trialling all sorts though dude, could have been core network fibre, could have been part of a trial to put fibre to street cabinets, a trial to get fibre to homes, or could have just been copper to replace existing stuff or add more capacity :)

Let's just say that ntl's sudden interest in developing their services isn't without some prompting from BT and LLU operators, good this competition malarky innit :D

---------- Post added at 21:27 ---------- Previous post was at 21:25 ----------

Nope dead right, with the advent of the gigabit and 10-gigabit metronets the RF/HFC network is where the bottleneck lies, same as every other way of getting the phatness to homes apart from obviously fibre/ethernet all the way.

---------- Post added at 21:27 ---------- Previous post was at 21:27 ----------

Ashford trial? Pre-DOCSIS 3 but same kinda thing, Ultra Wide Band (UWB) DOCSIS.

Re: Something for the geeks I found
 

Apparently thats what they wish to achieve someday: (23 to 25) http://www.ntl.com/locales/gb/en/inv...w-final-vr.pdf

But then again its not like they are going to dump the coax network any time soon after the investment put into it.