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dila125

join:2008-01-19

Frequent disconnects with 1801

Switched our 3com dsl router to an 1801 last week. However, ever since i've suffered stability problems with frequent disconnections.

They were every 5 mins, but I changed dsl operating-mode to itu-dmt and that has helped - now about every 30 minutes.

Having been searching on these forums, I suspect I may benefit from setting dsl noise-margin 3 on interface atm0, however this gives an invalid input error? Does the 1801 not support this command?

The results of show interface dsl atm0 are shown below if anyone has any other suggestions to improve things?

I read on one site that some lines just aren't good enough to support cisco routers - is that true? Does the output below suggest that might be the case?

ATM0
Alcatel 20190 chipset information
                ATU-R (DS)                      ATU-C (US)
Modem Status:    Showtime (DMTDSL_SHOWTIME)
DSL Mode:        ITU G.992.1 (G.DMT) Annex A
ITU STD NUM:     0x01                            0x1
Vendor ID:       'STMI'                          'TSTC'
Vendor Specific: 0x0000                          0x0000
Vendor Country:  0x0F                            0xB5
Capacity Used:   99%                             85%
Noise Margin:    14.0 dB                         11.0 dB
Output Power:    19.5 dBm                        12.5 dBm
Attenuation:     49.0 dB                         23.5 dB
Defect Status:   None                            None
Last Fail Code:  None
Watchdog Counter: 0x56
Watchdog Resets: 0
Selftest Result: 0x00
Subfunction:     0x00
Interrupts:      3936 (0 spurious)
PHY Access Err:  0
Activations:     21
LED Status:      ON
LED On Time:     100
LED Off Time:    100
Init FW:         embedded
Operation FW:    embedded
FW Version:      2.5.42
 
                 Interleave             Fast    Interleave              Fast
Speed (kbps):          4192                0           832                 0
Cells:               166020                0       2778111                 0
Reed-Solomon EC:        131                0             2                 5
CRC Errors:              92                0             1                 5
Header Errors:           89                0             4                 4
Total BER:                3616E-8                0E-0Leakage Avarage BER:
  3616E-8                0E-0
LOM Monitoring : Disabled
 
DMT Bits Per Bin
000: 0 0 0 0 0 0 6 8 9 A B B B B C B
010: B C B B B B B A A A A 9 9 7 6 0
020: 0 0 0 0 0 B B C C B B B A A 4 A
030: B B B B B B B B B B A B B B B A
040: 0 A 2 A 9 A 9 A A A A A A A A A
050: A A A A A 9 A A 9 9 9 9 9 9 9 9
060: 9 9 9 9 9 9 9 9 9 9 9 8 9 9 9 9
070: 9 9 8 9 8 8 9 9 9 9 8 8 8 8 8 7
080: 8 8 8 8 9 7 7 8 5 7 6 7 8 8 7 7
090: 7 7 7 7 6 7 7 7 7 7 7 7 7 6 6 5
0A0: 5 5 7 6 6 5 7 6 7 6 6 6 6 5 5 3
0B0: 4 3 4 5 5 5 4 4 3 2 0 0 0 0 0 2
0C0: 2 2 3 2 3 3 3 3 2 3 2 2 2 2 0 0
0D0: 0 0 0 0 0 0 0 0 0 2 2 2 2 2 2 2
0E0: 2 0 0 2 2 2 2 2 0 0 0 0 0 2 0 2
0F0: 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 
DSL: Training log buffer capability is not enabled
 

bigsy

join:2001-07-18
ireland
kudos:1

Try updating the Alcatel 20190 firmware. I believe versions 3.0.10 and 3.0.33 available from »ftp://ftp.cisco.com/pub/access/800/ are compatible with the 1801. The associated documentation gives details of the upgrade process. It is also likely that a newer IOS version also has a more recent DSL firmware included.


dila125

join:2008-01-19

Thanks, after I realised I had to rename the file once uploaded to the flash storage, it solved my problem.

Also found this which confirms it was a known fault with BT (UK) ADSL lines:
»cgi.tolien.co.uk/cisco-adsl/