Issue with Degrading Performance

Hi,

We have had a new dsl line installed which we use for VPN and have used this solution numerous times without any issues.

However, on this site the performance continually degrades over time (usually 1-3 days) and becomes unusable. A reboot resolves the issue temporarily. The router, filter etc have all been replaced to no effect and BT are insisting there is no fault at there end. We are using a cisco 877 router and the only thing I have noticed is that we get errors only on the downstream side. I have copied a sh dsl int result below. Any ideas?

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 0x71BE
Chip Vendor Country: 0x0F 0xB5
Modem Vendor ID: 'CSCO' ' '
Modem Vendor Specific: 0x0000 0x0000
Modem Vendor Country: 0xB5 0x00
Serial Number Near: FCZ1225613U
Serial Number Far:
Modem VerChip ID: C196 (0)
DFE BOM: DFE3.0 Annex A (1)
Capacity Used: 100% 100%
Noise Margin: 4.5 dB 6.0 dB
Output Power: 19.0 dBm 12.5 dBm
Attenuation: 53.0 dB 31.0 dB
Defect Status: None None
Last Fail Code: None
Watchdog Counter: 0xD5
Watchdog Resets: 0
Selftest Result: 0x00
Subfunction: 0x00
Interrupts: 8311 (0 spurious)
PHY Access Err: 0
Activations: 3
LED Status: ON
LED On Time: 100
LED Off Time: 100
Init FW: init_AMR-3.0.014_no_bist.bin
Operation FW: AMR-3.0.014.bin
FW Source: embedded
FW Version: 3.0.14

DS Channel1 DS Channel0 US Channel1 US Channel0
Speed (kbps): 0 5457 0 935
Cells: 0 325843 0 22286910
Reed-Solomon EC: 0 0 0 0
CRC Errors: 0 6161 0 0
Header Errors: 0 20635 0 0
Total BER: 0E-0 1183E-6
Leakage Average BER: 0E-0 9438E-7
Interleave Delay: 0 21 0 59
ATU-R (DS) ATU-C (US)
Bitswap: enabled enabled
Bitswap success: 0 0
Bitswap failure: 0 0

You need to keep a record of the following settings over a period of time to see if they flucuate

Noise Margin: 4.5 dB 6.0 dB
Output Power: 19.0 dBm 12.5 dBm
Attenuation: 53.0 dB 31.0 dB
Speed (kbps): 0 5457 0

It may be the 4.5dB downtream margin is wandering down ever closer to zero (not good). What phone wiring do you have in the property? This can have a massive effect on performance.

Looks like you are on a very long line (53.0dB) and on ADSL2+.

It may be best to consult your ISP and get them to switch you over to ADSL1. It usually works better on longer lines.

With a cisco you should be able to force the various modes, and ADSL2 should be perfectly good on 53dB attenuation. ADSL2+ is G.992.5

Yes, I spotted that but from experience, if ADSL2+ is running on a long line and it is experiencing a high error count, a good fix is usually switching it over to ADSL1.

Thanks, As i can change to DSL mode myself I will try this first.

But the OP is showing ADSL2, not 2+.

That should be optimum at 53dB, but leaves open the question of why it isn't on G.992.5 (ADSL2+).

Edited by RobertoS (Thu 14-Apr-11 12:26:28)

Are you talking wired or wireless speed degradation?

An exchange VP check that is sometimes useful, though not as reliable as at one time, is this one.

In reply to a post by MrSaffron:

Noise Margin: 4.5 dB 6.0 dB
Output Power: 19.0 dBm 12.5 dBm
Attenuation: 53.0 dB 31.0 dB
Speed (kbps): 0 5457 0 935

Also this line:

DSL Mode: ITU G.992.3 (ADSL2) Annex A

and add US Speed.

@ chris6273: OP is already on ADSL2!

Where's the degradation exactly? Do you mean speed tests? What are they?

Your Sync is good for your line.