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. 
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. 
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. 
The VLIW cores exploit Instruction Level Parallelism to concurrently crunch five or more basic operations per instruction word. 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.  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 
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. 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.
 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.
Edited by asbokid (Thu 03-Nov-11 12:43:26)