Opt3 with fibre and Infinity use the same modem so it is unlikely your attempted order initiated it

In reply to a post by orly:

While they likely can tell what hardware version you have plugged in, it's also likely they simply have a list of serial numbers and who they were shipped to.

From what I have seen, the technician just takes one from the batch he has and does not rrecord the serial number.

Have you measured the internal heating temperature?

no i havent, i have never senn the need really as its nowhere near anything that gets hot, and its only slightly warm to the touch. basically its on top of a bench well ventilated behind my monitor,

Yep, and then you see your mate down the exchange at lunchtime, and you have to let him have a couple 'cos he's run out. So pretty much untraceable.

The Huawei will become obsolete when BT rolls out Profile 30a, if my back-of-envelope calculations are right.

The 6368 chipset in the Huawei just doesn't run fast enough to support a VDSL2 Profile beyond 17a. According to Broadcom, the CPU can be clocked at up to 400MHz. [1]

VDSL2 Profile 30a supports a bandwidth of up to 200Mbps. The AFE in the modem must have a sampling rate that is at least twice the highest frequency found in the signal to satisfy Nyquist's Theorem. [2]

The CPU has got to shift that data from the AFE into DRAM and process it. Not least shuffle the bits from each frequency bin to recover the ethernet frames from the bitstream. All of that processing will gobble clock cycles, and the Huawei just ain't up to the job at speeds approaching 200Mbps.

Where VDSL2 Profile 30a is already in use - in various cities across the USA, for example - the CPE is based on the Trimedia VLIW cores rather than the MIPS cores found in Broadcom chipsets. [3]

The VLIW cores exploit Instruction Level Parallelism to concurrently crunch five or more basic operations per instruction word.[4] This parallelism particularly suits the DSP demands of broadband access equipment. If the modem maker can fully utilise that parallelism, through clever coding and toolchain design, the Trimedia can process five or even eight times the data at the same clock speed (~500MHz) as a single pipelined RISC core, like the MIPS.

Broadcom is apparently moving over to ARM cores. [5] Maybe that move is in tacit recognition of the MIPS' limitations in future applications. It's very bad news for MIPS Technology which relies on Broadcom for 30% of its sales. And it's a shame because it is a beautifully simple architecture that has stood the test of time. It's nearly 30 years since the MIPS core was spun out of John Hennessy's research at Stanford [6]

Pure speculation here, but I wouldn't be surprising if BT is in discussion with Pace plc over the supply of new CPE for VDSL2. Pace recently acquired 2Wire, the US maker of broadband access equipment.[7] All of 2Wire's kit is based on the Trimedia VLIW core.

BT already supplies 2Wire equipment to its top-end customers. BT's range of "Business Hub" are all 2Wire re-brands. Now that 2Wire is British-owned, negotiations over the supply of VDSL2 CPE to BT would be easier for both BT and Pace.

Pulling off the take-over of 2Wire was quite a coup for Pace since 2Wire has major contracts around the world to supply CPE to telco giants like AT&T.

[1] http://www.icmaster.com/Datasheet.ashx?mfg=4128&part...

[2] http://en.wikipedia.org/wiki/Nyquist_rate

[3] https://apps.fcc.gov/oetcf/eas/reports/ViewExhibitRe...

[4] http://en.wikipedia.org/wiki/Very_long_instruction_word

[5] http://www.eetimes.com/electronics-news/4213168/ARM-...

[6] Dominic Sweetman's book "See MIPS Run" is a really good read on the architecture. Sweetman has a passion for a subject you would expect to be as dry as dust! In the 2nd edition of the book Sweetman covers the Linux MIPS port used in the Huawei.

[7] http://www.pace.com/Documents/Investors/101001_2wire...

Edited by asbokid (Thu 03-Nov-11 12:43:26)

Good old Nyquist!




BT are about to start a trial of a new Business Hub 3. Could it be that it is a 2wire/Pace v5700/5500/2500 which will cater for 30a ? It has ADSL and VDSL2 interfaces wireless "n" and Gbit Ethernet.

The 200Meg options are probably some way away, i.e. three or more years I'd hazard

By which time CPE may not even be supplied by Openreach

Three years?!

It's sad how far things have slipped in Britain. Profile 30a is already a reality in places we wouldn't expect it, like the former Soviet-bloc countries and in Latin America.

It's doubtful that the Huawei (or any other Broadcom-based VDSL2 CPE device) is even capable of the theoretical max bandwidth of Profile 17a (100Mbps). In the meantime until superior kit is sourced, maybe BT will limit the demands on the Huawei by nobbling the training sequence at the DSLAMs.

Edited by asbokid (Thu 03-Nov-11 13:03:03)

VDSL2 rollout planned ends in 2014, then the work on the next third according to how contracts go.

I bet BT Martlesham Heath has been working on 30a, in fact they are often heavily involved in the profiles and standard setting.

Some countries adopt a deploy it and fix the problems attitude, the UK has a frequency plan to avoid causing problems for other xDSL services in the local loop.

If people buy the 40 and 80Meg services in their millions then am sure another speed tier will appear. For now there is no real justification for faster than that other than bragging rights.