ADSL line / router - Much oddness here!

[#Chri5#]

Bog standard ADSL connection via Enta, router is/was a Cisco 857.

Site was fine until a few weeks ago and went off-line. Investigations showed it wasn't synch'ing.

Bit of leg work later, we tried a (cheap & nasty) Billion 7402R2 which sync's but has the world's most unstable VPN tunnels.

I'm working on the problem today and I've got 3 Cisco 857s with me. One is the original router, the CD light just flashes a lot. The 2nd 857 with the same config as the 1st 857 on does the same. The 3rd 857 is brand new and I've done a very basic config on the ADSL interface and that just sits there flashing the CD light too.

I've also got a Draytek Vigor 100 - that won't sync.

However, the Billion 7402R2 sync's within 30 seconds of connecting it and reports 3,584,000 downstream and 736,000 upstream. Line stats are:

Downstream : 12.5db SNR, 48.5db Attenuation
Upstream : 5db SNR, 29db Attenuation

Next up I've tried a Speedtouch 546 v5. That sync'd, dropped the DSL and then has stayed up. This is showing:

Bandwidth (Up/Down) [kbps/kbps]: 832 / 3,392
Output Power (Up/Down) [dBm]: 12.0 / 18.5
Line Attenuation (Up/Down) [dB]: 29.5 / 47.5
SN Margin (Up/Down) [dB]: 6.0 / 14.0

The routers all go into the master socket which has a faceplate from an OCuk competitor that sells (IMHO) good quality filters.

Doing a quiet line test via 17070 shows nothing static-wise.

Is this just a really noisy line and the Cisco + Draytek routers can't hack it?

 

[PistolPete]

I found the if anything my Ciscos were more stable than anything else albeit that they didn't sync as high. I had a 837, and 1721 with 1xWIC-1ADSL and an 1841 with 2xWIC-1ADSLs and my line was MUCH worse that yours.

Of the top of my head I had 59dB loss and at 6dB margin I'd get about 3.5Mb and I was getting upto 16,000 HECs a second and it still chugged along fine.

You've got a 14dB margin so that shows signs that something has been playing up to increase it.

 

[#Chri5#]

It's very strange.

I've tried some of the newer Cisco ADSL firmware files - 3.0.10 and 3.0.33 but still no sync. I've also manually specified the DSL operating-mode instead of using "dsl operating-mode auto"

I've just synch'd up the Speedtouch again and that reports these vendor codes:

Vendor ID (Local/Remote): TMMB / P

Who is P?

I've just logged onto a couple of other 857s I know are working and they report STMI, TSTC or ALCB. They are running on the built in ADSL firmware (3.0.14).

 

[#Chri5#]

Would you believe it?

Both the 1st 857 and the Vigor 100 sync'd on my home Enta line with no configuration changes...

So what do BTW do to a break a line for certain CPE?