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ADSL - BER valid sec:

I have many 1720 ADSL / VPN bundle routers deployed. I am having a problem using NFS across one of many. I see no errors recorded on the interfaces, but i do notice one difference on the router in question. A very high number in the BER valid seconds when using the command sh dsl int atm0. All the other routers display 0 in this field.

Any Ideas?

Here is the output:

Alcatel 20150 chipset information

ATU-R (DS) ATU-C (US)

Modem Status: Showtime (DMTDSL_SHOWTIME)

DSL Mode: ANSI T1.413

ANSI Issue/rev: 2/1 2/1

Vendor ID: 0x0022 0x0022

Capacity Used: 12% 25%

Noise Margin: 38.0 dB 31.0 dB

Output Power: 20.0 dBm 12.0 dBm

Attenuation: 31.0 dB 21.5 dB

Defect Status: None None

Last Fail Code: None

Selftest Result: 0x00

Subfunction: 0x15

Interrupts: 97850 (0 spurious)

PHY Access Err: 0

Activations: 3

SW Version: 3.8129

FW Version: 0x1A04

Interleave Fast Interleave Fast

Speed (kbps): 0 864 0 160

Reed-Solomon EC: 0 0 0 0

CRC Errors: 0 0 0 0

Header Errors: 0 0 0 0

Bit Errors: 0 0

BER Valid sec: 0 3007774

BER Invalid sec: 0 0

DMT Bits Per Bin

00: 0 0 0 0 0 0 0 0 0 0 2 2 3 4 4 4

10: 4 4 4 4 4 4 3 3 3 2 2 2 2 2 0 0

20: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

30: 0 0 0 0 0 0 2 2 2 2 2 2 2 2 2 2

40: 2 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3

50: 3 3 2 2 2 2 2 2 2 2 2 2 3 3 3 2

60: 3 4 3 3 3 3 3 2 3 3 3 3 3 3 3 3

70: 2 2 2 2 2 2 2 2 3 2 2 2 2 2 2 0

80: 0 2 2 2 2 2 2 2 2 2 2 2 0 2 2 2

90: 2 2 2 2 2 2 2 2 2 2 2 2 2 2 0 0

A0: 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

B0: 2 2 2 2 0 2 2 0 0 0 0 0 0 0 0 0

C0: 0 0 0 2 2 2 2 2 0 0 0 0 0 0 0 0

D0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

E0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

F0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1 REPLY
Silver

Re: ADSL - BER valid sec:

1)BER Valid is actually errored seconds (ES). BER valid seconds and invalid seconds are counters of the number of seconds over which BER data has been calculated. This can be used together with the total number of bit errors to figure out the actual bit error rate. A BER valid second means that it is a valid measured second, during

which any number (including 0) of bit errors could occur. Thus, on a very clean line, you would have 0 bit errors, but a large number of BER valid seconds.

This BER information is only transmitted during spare bandwidth. So it will never slow down your data. If you're doing an FTP and saturating the link, no bit

error data will be sent, and so the BER valid seconds will not increase. In essence there is no need to get alarmed on this value.

2)The BER invalid seconds means that you got so many bit errors during a second that the chipset could not measure the actual number of bit errors.This error can be

either a header error, transient spike noise, or a really bad line (if it happens over and over) which should be taken care.

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