I’m glad I could help!
One thing I will caution you when you run into CPE bugs - and you inevitably will - CPE vendors always try and blame the ACS. The way I’ve found to beat them at that finger pointing game is hit them with the soap conversations and then always point back to the spec where their device isn’t conforming. Because their standard response is going to be “works for me.”
My favorite is one vendor told me “None of our other customers are having these issues” and I responded back, “yeah, because none of them are actually using the features of the CPE”, like DHCP option 43. Because if they were, they’d be filing defect reports too…
If you haven’t looked into DHCP option 43, I would encourage you to use it if at all possible. It allows the CPE to get the ACS URL from DHCP. This makes it really, really easy to swap CPEs between a dev and prod environment. Absolutely no intervention is needed on your part.
To give a more concrete example, in my office all my (both DSL and eth wan) are configured for untagged traffic is PPPoE, and CPE mgmt is vlan 4 (our CPEs are configured with two WAN services per interface - one for PPPoE, one for CPE management). When the CPE gets its DHCP on the mgmt interface, it also gets the IP of our dev acs instance via DHCP option 43.
In the field, the dhcp server on vlan 4 (CPE mgmt) gives out the acs URL for our production ACS server.
If you are using DSL, one thing that was a huge time saver for our support guys is being able to pre-qualify loop issues. The CPE and DSLAM support whats called a DELT - duel ended line test. And with the diagnostic data that comes back, you can plot it out and see why the customers loop might be having issues. I don’t have anymore examples of really bad loops, but here is an example DELT on a CPE in our office, so the loop is really short and doesn’t show any real issues.
If this loop had huge spikes on the QLN, that would be an indicator that there is bonding/grounding issues with the loop. And those spikes are usually at the frequency of nearby AM radio stations. If the HLog has a valley (not that dip you see at 1,850khz in this picture), thats an indication there is a bridge tap.