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Author Topic: VDSL Modems for FTTC services  (Read 29984 times)

waltergmw

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VDSL Modems for FTTC services
« on: August 03, 2011, 10:01:07 AM »

Gentlefolk,

The OR provided VDSL modem thread is technically quite fascinating for some:-

http://forum.kitz.co.uk/index.php?action=post;topic=9503.0;last_msg=196096

However I expect there are plenty of simple (as in uncomplicated) folk who would like a faster and reliable FTTC broadband service without being the experimenters.
Furthermore some simple method of monitoring the line performance, especially for long or poorly performing twisted pairs will be even more important that it already is.

To that end could we start with some straight-forward questions:-

Is a standard (Vanilla flavour firmware) VDSL2 modem compatible with the service being delivered by BT Openreach ?

If so, can we list models and prices ?

What diagnostic facilities are available with each modem ?

Are there any monitoring programs such as Routerstats available for these modems?

Kind regards,
Walter
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burakkucat

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Re: VDSL Modems for FTTC services
« Reply #1 on: August 03, 2011, 05:04:02 PM »

Being the one responsible for starting The OR provided VDSL modem thread, I shall assist here by posting details of devices that I understand other people have used with their FTTC connections in place of the OR provided VDSL modem.

(1) Billion BiPAC 8200M
(2) Billion BiPAC 8200N
(3) FRITZ!Box Fon WLAN 7390
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asbokid

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Re: VDSL Modems for FTTC services
« Reply #2 on: August 04, 2011, 02:43:25 AM »

Zyxel P-2812HNU-51c (around £200.)



The Zyxel uses the same Broadcom 6368 processor that is used the Huawei, so the performance is likely to be identical (but hopefully with no overheating). The 6368 is a widely used and very capable processor, and Zyxel will have spent some time polishing the user interface, hence the price.

ChinaTelecom supplies the Dare Tech DB120-B2+ as its CPE for ADSL2+/VDSL2 services.   Again this is a 6368-based device, so performance will match the Huawei.  It retails for 258 yuan in China (£25). There's a market for these in Britain for anyone who knows their way around the Chinese import business.

Below are some photos of the Dare Tech DB120-B2+.  This is what the BT Openreach VDSL2 modem could (and perhaps should) have been.....






Larger pics and discussion (translated from Chinese) at wifizoo.net
« Last Edit: November 27, 2011, 03:53:35 AM by asbokid »
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hairydog

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Re: VDSL Modems for FTTC services
« Reply #3 on: January 27, 2012, 09:46:04 PM »

Quote from: burakkucat link=topic=9707.msg196168#msg196168 date=1312387442}I shall assist here by posting details of devices that I understand other people have used with their [b
FTTC [/b] connections in place of the OR provided VDSL modem.
[snip]
(3) FRITZ!Box Fon WLAN 7390

What settings would be needed to replace the BT modem with one of these? Does it need a specific username and password as you do with a non-fttc adsl modem setup?
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GunJack

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Re: VDSL Modems for FTTC services
« Reply #4 on: March 12, 2012, 09:03:18 AM »

guys, now I have a date for FTTC on my exchange (jan 13 !!) I'm starting to take more of an interest in these things :) Does anyone know what kit talktalk are supplying for fttc, and whether anyone knows of plans to import the Dare router into UK as yet??  I've looked at the other models mentioned above, but they're hoofin' expensive :(
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AdrianH

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Re: VDSL Modems for FTTC services
« Reply #5 on: March 12, 2012, 09:18:36 AM »

DrayTek Vigor 2750n   and   Thompson/Technicolor TG789vn  both are supposed to be good. Wouldn't know personally as I reckon it will be another century or two before we see any upgrades here.
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asbokid

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Re: VDSL Modems for FTTC services
« Reply #6 on: March 12, 2012, 10:07:09 PM »

guys, now I have a date for FTTC on my exchange (jan 13 !!) I'm starting to take more of an interest in these things :) Does anyone know what kit talktalk are supplying for fttc, and whether anyone knows of plans to import the Dare router into UK as yet??  I've looked at the other models mentioned above, but they're hoofin' expensive :(

The DB120-B2+ is selling for less than £20 now. [1] 

The main problem is the modem GUI. It is in Chinese because these are CPE shipped by China Telecom for its FTTC service.   It could all be translated into English and the firmware rebuilt, but that's quite a lot of effort.

The Dare firmware is, at least, unlocked or, rather, never was locked. 

This is what the GUI looks like:








For anyone who wants to import, there are trustworthy individuals in China (taobao agents) who negotiate, inspect, pay and ship on others' behalf. Nevertheless it's easy to get stung by all manner of scam.

cheers, a

[1] http://s.taobao.com/search?q=db120-b2%2B&sort=total-asc
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GunJack

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Re: VDSL Modems for FTTC services
« Reply #7 on: March 12, 2012, 11:32:22 PM »

cheers for that asbo, however my language skills in Mandarin are non-existant :(

oh well, if I go FTTC, I'll just have to rely on whatever TT dish out.........
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Blackeagle

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Re: VDSL Modems for FTTC services
« Reply #8 on: March 13, 2012, 12:35:14 AM »

Hmmmm, from the screenies, most of what you need to set it up is in english.  As its the same chipset as the Huawei, I'm guessing it'll work with the modded DMT.  If that is indeed the case, I have some friends who may be able to help with a translation.

Question, would it need to be Jtagged to obtain a full firmware dump for the translation, or is there an easier way ?

At £20 its gotta be worth a punt.

Quote
oh well, if I go FTTC, I'll just have to rely on whatever TT dish out.........

HG532 as router, BTOR supplied modem, hopefully the HG612.  Failing that, I believe you can use any router behind the modem that has a WAN uplink port or a LAN port that can be configured as such.  AFAIK, TT are now authenticating on CLID rather than 01xxxxxxxxx@talktalk.net with corresponding password.  Such is reported on the talktalk members forums anyway.  If this is indeed the case (and I haven't tested it myself !!), then any router sat behind the 612 or ECI should be able to connect.

Apologies for the off-topic post  :-[
« Last Edit: March 13, 2012, 12:56:50 AM by Blackeagle »
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asbokid

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Re: VDSL Modems for FTTC services
« Reply #9 on: March 13, 2012, 01:41:55 AM »

would it need to be Jtagged to obtain a full firmware dump for the translation, or is there an easier way ?

JTAG, if Broadcom hasn't blown an internal fuse to prevent that, or else connect to the CFE bootloader shell via UART, and dump the contents from that:

http://www.wifizoo.net/viewthread.php?tid=43049&rpid=297866&ordertype=0&page=1#pid297866

With the NAND contents on the PC, extract the firmware components..
Unsquash the root file system (hope it hasn't been nobbled like the ECI)..
Translate all those web-page resources from Chinese into English.
Build a new file system image from the modified files
Combine the file system image with the original kernel image
Package it up in standard Broadcom f/w format for flashing back in again.

Quote
At £20 its gotta be worth a punt.

Tempting, isn't it?!

cheers, a
« Last Edit: March 13, 2012, 01:44:57 AM by asbokid »
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asbokid

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Re: VDSL Modems for FTTC services
« Reply #10 on: March 13, 2012, 01:53:55 AM »

cheers for that asbo, however my language skills in Mandarin are non-existant :(
Me neither!

Cut-and-pasting into http://translate.google.com usually works fine for raw text, but when the Chinese 'logograms' (characters) are part of a graphic image, e.g. Chinese text on a JPEG button of the GUI or in a GIF web banner, translating it becomes very difficult!

According to wonkypedia, "functional literacy [of Mandarin Chinese] requires a knowledge of between three and four thousand characters" !

Sounds like a job for a Mahjongg expert!

Quote
oh well, if I go FTTC, I'll just have to rely on whatever TT dish out.........

Not sure about the router, but the VDSL2 modem will be an HG612 or an ECI B-Focus (as supplied by BT Openreach).

cheers, a

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GunJack

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Re: VDSL Modems for FTTC services
« Reply #11 on: March 13, 2012, 11:58:27 AM »

I get the distinct impression that ALL the ISPs in this country are missing a trick here.....why on earth have they gone for separates and not gone for VDSL modem/routers a la ADSL ???????
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burakkucat

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Re: VDSL Modems for FTTC services
« Reply #12 on: March 13, 2012, 08:36:59 PM »

GJ,

The ISPs do not have a choice. They are using the Openreach NGA product and the specification is that the active NTE is part of the Openreach circuit.  :-X

From the Openreach perspective that ensures a standard device across the entire installation range, of which they are familiar and as long as the circuit performs within specification at the modem's LAN1 port, the installation can be signed off as O.K.  :-\
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GunJack

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Re: VDSL Modems for FTTC services
« Reply #13 on: March 13, 2012, 11:05:30 PM »

b*cat, the active NTE I can understand, but OR could have just as easily made the consumer unit a full-blown modem/router as opposed to just a modem  >:(

Do they not realise that the days of a single internet-enabled device in a household have come, bought the t-shirt, worn it out and recycled it already  :no:
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asbokid

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Re: VDSL Modems for FTTC services
« Reply #14 on: March 14, 2012, 12:40:13 AM »

It may also be down to processing power, or lack of.   Splitting the load between a modem and a router is perhaps done for performance, i.e. to increase throughput.

Tasks like packet inspection for firewalling and network address translation (re-writing packet headers) are costly in terms of clock cycles.  The CPU in the VDSL2 modem is already handling the demodulation/modulation of an up-to 30MHz signal.

Once the symbols have been recovered from the QAM-modulated subcarriers by the DSP engine, they've got to be re-assembled into a bitstream.  Then that bitstream has to be (re-)encapsulated into ethernet frames. Only then can it be wired out over a LAN port to the PCs in the consumer premises. By design, that is done in the most efficient way possible - in the raw, with no TCP layering.

At a guess, all that processing is already pushing the performance limits of a 400MIPS CPU (the Broadcom 6368). Expecting the CPU to also perform routing and firewalling etcetera is possibly expecting too much from such a humble beast. The MIPS32 cores in the Broadcom SoCs date to the mid-1980s, when they were used in 'top-of-the-range' Unix desktop machines.  For the same purpose, the MIPS32 is basically obsolete nowadays.

Today, AT&T (a much better funded telco than BT) supplies a VDSL2 modem-router which is driven by a 400MHz dual core five issue slot Trimedia TM3260 CPU. The TriMedia is a dedicated media processor. The VDSL2 CPE supplied by AT&T is the 2Wire 3801HGV.  Arguably, it is about the best VDSL2 modem router for CPE that money can buy.   The big selling point of the TriMedia is its instruction level parallelism (ILM).  A dual core five issue slot VLIW CPU, like the TriMedia can simultaneously execute ten primitive operations every clock cycle.  And many of those operations were explicitly designed for digital signal processing needs.

With 10 ops per clock cycle (ignoring costly branches and jumps) this means that in theory, the effective processing power of the TriMedia, compared to a single pipelined CPU like the MIPS32 in the Huawei or the ECI, is boosted by a factor of ten. (In practice, however, it's very difficult to actually exploit all that parallelism to the full).

For argument's sake though.. if a MIPS32 processor, like the CPU found in the Huawei HG612, can perform one operation every clock tick, then it can crunch 400 million instructions per second (400MIPS).

By contrast, the dual-core Trimedia used in the AT&T VDSL2 modem-router, can crunch ten times that (4GIPS).  That's comparable on raw processing power to a single core Intel Atom. Still pants, by desktop standards, but nevertheless ten times better than the Huawe or the ECI.

Yet AT&T's end-users are still complaining that when their modem-routers are placed under a moderate load, e.g. when routing the traffic for seven separate PCs over that single VDSL line,  the 2Wire is still grinding to a halt!

IMVHO, the Martlesham egg-heads have probably done the right thing by splitting the load between a router and a modem.  The Huawei will cost less than £10 in volume, perhaps as little as £5.  AT&T's modem-router probably costs over £50.   To install CPE that will be future-proofed for VDSL2 Profile 30 (and above) could easily cost over £100 per premises.

cheers, a
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