The Broadcom BCM6368 is the embedded processor powering the HG612 and a good many other VDSL2 CPE.
The processor reportedly supports Profile 30a, yet we cannot get the device to sync on Profile 30a. We tested with a 30MHz Huawei H835VDGE linecard. It has a Broadcom BCM6516 dual chipset.
The DSL layer of the CPE repeatedly tries to auto-negotiate down to Profile 17a. When the MA5616 DSLAM with V800R310 firmware is configured to disable that downwards auto-negotiation, the CPE won't sync at all.
One of the other Openreach VDSL2 CPE is the ECI vg3503j. It is known also as the /r revision model. By contrast, that ECI device does sync with a Profile 30a line profile.
Though even with a zero loop (a loop of effectively zero length), the outcome is not that impressive. With the IP profile removed, the line sync rate is still only ~105Mbps up and ~115Mbps down. Not to be sneezed at, but nowhere near the 200Mbps theoretical maximum!
That experiment was using a PSD class mask of AnnexB998ADE30-M2x-NUS0-A (B8-16) which is the nearest 30MHz equivalent to the AnnexB998ADE17-M2x-A (B8-11) mask used by BT Openreach for its Profile 17a service.
cheers, a
P.S. For those interested, here is the line operation data when the ECI /r is synced on Profile 30a:
| Text |
1
23
45
67
89
1011
1213
1415
1617
1819
2021
2223
2425
2627
2829
3031
3233
3435
3637
3839
4041
4243
4445
4647
4849
5051
52 | MA5616(config-if-vdsl-0/3)#display line operation 0
------------------------------------------------------------------------------ Standard in port training : G.993.2-Annex B
Current power management state : Full-on state Result of the last full initialization : Communication fail
G.998.4 retransmission used downstream : Unused, retransmission mode is forbidden G.998.4 retransmission used upstream : Unused, retransmission mode is forbidden
Signal attenuation downstream(dB) : 15.6 Signal attenuation upstream(dB) : 0.0
Line attenuation downstream(dB) : 15.6 Line attenuation upstream(dB) : 0.0
Maximum attainable rate downstream(Kbps) : 100014 Maximum attainable rate upstream(Kbps) : 108708
Actual line rate downstream(Kbps) : 116560 Actual line rate upstream(Kbps) : 105192
Line SNR margin downstream(dB) : 25.4 Line SNR margin upstream(dB) : 8.8
Actual PSD downstream(dBm/Hz) : - Actual PSD upstream(dBm/Hz) : -
Actual KL0_CO value(0.1dB) : 0 Actual KL0_CPE value(0.1dB) : 0
Total output power downstream(dBm) : 12.0 Total output power upstream(dBm) : 7.2
Current VDSL2 profile : Profile30a Coding gain in downstream(dB) : -
Coding gain in upstream(dB) : - Power cut back downstream(dB) : -
DS1 band: Signal attenuation(dB) : 15.6
Line attenuation(dB) : 15.6 Line SNR margin(dB) : 25.9
US1 band: Signal attenuation(dB) : 0.0
Line attenuation(dB) : 0.0 Line SNR margin(dB) : 8.9
DS2 band: Signal attenuation(dB) : 8.9
Line attenuation(dB) : 8.8 Line SNR margin(dB) : 25.9
US2 band: Signal attenuation(dB) : 0.0
Line attenuation(dB) : 0.0 Line SNR margin(dB) : 8.8
DS3 band: Signal attenuation(dB) : 0.2
Line attenuation(dB) : 0.2 Line SNR margin(dB) : 25.2
US3 band: Signal attenuation(dB) : 1.4
Line attenuation(dB) : 0.3 Line SNR margin(dB) : 8.8
------------------------------------------------------------------------------ |
Edited by deleted (Fri 17-May-13 02:36:41)
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Bobby_Valentino
