Question : Help with Cisco bonded ADSL

I'm no Cisco expert and I certainly don't understand the underlying workings of bonded ADSL so hoping for some help with this please.

We ordered bonded ADSL and using a Cisco 2811 bonding 4 lines.  Now there was an issue with one of the lines initially but BT sorted that out, now we seem to get high throughput for a minute or so and then it drops down to abysmal speeds, around 4k per second.  So it's making the whole solution unusable.

Any ideas on how I can get to the bottom of this?  The ISP behaves like they don't understand the underlying technologies either - they've now asked us to take one line out at a time and do speed tests to see if an individual line is causing this.  This makes sense but they keep coming up with things like this which means I have to take time to go on site to run these diagnostics, only to push the results back to them and have them come back to me with more things to do on site.

I can telnet to the Cisco and run SDM remotely so if there are any diagnostics you can recommend.

Thanks!

Answer : Help with Cisco bonded ADSL

I chewed through the ADSL line parameters. Lines 1 and 3 are achieving the full 8128 speed which is pretty good on a 44 dB attenuation. Lines 0 and 2 fall a bit short of that. All four upstreams are at the full 832 rate for ADSL1.

Assuming these are BT Wholesale circuits the IP Profiles will be

7000
7150
6500
7150

I'm not sure how the load balancing algorithm copes with these external constraints, but as a starter for 10 I would try running just lines 1 and 3 as they have the full 8128 sync speed and hence 7150 IP profile = 6700 kbits/s of data each downstream.