Cisco 877 and BT Problem

Answered Question
Sep 3rd, 2010

Good Afternoon

I'm having trouble with the sync speed of a new 877, to a newly installed BT ADSL line.  I realize there are many threads regarding this issue, and have tried the various DSL firmwares suggested in the forums including 4.0.017 and 4.0.018. Have also tried with the various DSL operating modes. All pretty much sync at the same speed.

The line has been live for 3 days, BT will not assist at the moment as the line is still in the training period.  However the line will not achieve a downstream speed higher than 600Kbps, the upstream speed also appears to be consistantly slightly higher. I notice the downstream attenuation isnt great, however i would of thought we would still be looking at 4-8Mbps connection.

Ive included the interface details below, and suggestions, things to try or advice appreciated.

Regards

Paul

BUD-RT-877#show dsl int atm 0
ATM0
Alcatel 20190 chipset information
                                    ATU-R (DS)                      ATU-C (US)
Modem Status:              Showtime (DMTDSL_SHOWTIME)
DSL Mode:                    ITU G.992.3 (ADSL2) Annex A
ITU STD NUM:               0x03                              0x2
Chip Vendor ID:            'STMI'                              'IFTN'
Chip Vendor Specific:    0x0000                           0x71B9
Chip Vendor Country:    0x0F                              0xB5
Modem Vendor ID:        'CSCO'                           '    '
Modem Vendor Specific:0x0000                          0x0000
Modem Vendor Country:0xB5                             0x00
Serial Number Near:     FCZ143293NS
Serial Number Far:
Modem VerChip ID:        C196 (3)
DFE BOM:         DFE3.0 Annex A (1)
Capacity Used:            99%                             100%
Noise Margin:              5.5 dB                          6.0 dB
Output Power:             13.5 dBm                        12.5 dBm
Attenuation:                 60.0 dB                         36.0 dB
FEC ES Errors:            0                               0
ES Errors:                   1                               0
SES Errors:                 1                               0
LOSES Errors:             1                               0
UES Errors:                 0                              330
Defect Status:             None                            None
Last Fail Code:  None
Watchdog Counter: 0xEC
Watchdog Resets: 0
Selftest Result: 0x00
Subfunction:     0x00
Interrupts:      13099 (0 spurious)
PHY Access Err:  0
Activations:     1
LED Status:      ON
LED On Time:     100
LED Off Time:    100
Init FW:         init_AMR_4.0.018.bin
Operation FW:    AMR-E-4.0.018.bin
FW Source:       external
FW Version:      4.0.18

                 DS Channel1      DS Channel0   US Channel1       US Channel0
Speed (kbps):             0              519             0               568
Cells:                    0           395898             0          12928903
Reed-Solomon EC:          0                0             0                 0
CRC Errors:               0                3             0                 0
Header Errors:            0                1             0                 0
Total BER:                0E-0           2467E-11
Leakage Average BER:      0E-0           2678E-11
Interleave Delay:         0               33             0                36
                        ATU-R (DS)      ATU-C (US)
Bitswap:               enabled            enabled
Bitswap success:          0                   0
Bitswap failure:          0                   0

LOM Monitoring : Disabled


DMT Bits Per Bin
000: 0 0 0 0 0 0 6 7 8 8 9 9 8 8 8 8
010: 8 8 7 7 6 6 6 6 5 4 4 4 4 4 2 2
020: 0 4 5 6 7 8 8 5 6 5 5 4 4 4 5 7
030: 7 7 2 4 2 4 0 2 0 0 0 1 2 0 1 0
040: 1 0 2 1 2 2 2 3 1 0 0 1 0 2 0 2
050: 0 4 2 1 1 0 2 0 1 0 0 0 0 0 0 0
060: 1 0 1 2 0 0 0 1 0 0 0 0 0 0 0 0
070: 1 0 2 1 1 0 1 2 0 0 0 0 0 0 0 0
080: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
090: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0A0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0B0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0C0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0D0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0E0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0F0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Log file of training sequence:
AMR-4.0.18.
subfunction: 0
# opens since reset : 3
# seconds : 20
# forced LOSs : 0

I have this problem too.
0 votes
Correct Answer by Giuseppe Larosa about 6 years 2 months ago

Hello Paul,

I'm afraid the line has too much attenuation and as a result of this you can only get 600 kbps downstream

see

>> Capacity Used:            99%                             100%

Noise Margin:              5.5 dB                          6.0 dB

Output Power:             13.5 dBm                        12.5 dBm

Attenuation:               >>  60.0 dB       <<                  36.0 dB

I have seen lines with 20-30 dB of noise margins, if there is no noise margin the modem cannot try to use more bits per tone and so it cannot achieve faster speeds. Ask BT to qualify the line

Hope to help

Giuseppe

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Correct Answer
Giuseppe Larosa Sat, 09/04/2010 - 03:17

Hello Paul,

I'm afraid the line has too much attenuation and as a result of this you can only get 600 kbps downstream

see

>> Capacity Used:            99%                             100%

Noise Margin:              5.5 dB                          6.0 dB

Output Power:             13.5 dBm                        12.5 dBm

Attenuation:               >>  60.0 dB       <<                  36.0 dB

I have seen lines with 20-30 dB of noise margins, if there is no noise margin the modem cannot try to use more bits per tone and so it cannot achieve faster speeds. Ask BT to qualify the line

Hope to help

Giuseppe

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