Underprovisioned, I say

My DSL speed problems persist. Every night at around 9:00, download speed drops to unusable. I’ve been working around it by downloading mail earlier or later. I’m convinced that Verizon has underprovisioned the DSLAM to which I’m connected. Now, someone has backed me up.

Nate Anderson accurately describes my problem in his article "Why you’ll never see 200Mbps from a 200Mbps ‘Net connection." Anderson spends most of the article talking about how cable modems share reqources, but he does mention DSL where he says "DSL is not a shared architecture in the last mile; each DSL link runs over dedicated copper from a DSLAM port in the local office to a customer’s home. The whole office must be connected to a backhaul network, though, which is generally fiber, and problems can crop up here if a central office is underprovisioned."

I forwarded the article to my favorite support technican at my ISP.

On the topic of provisioning, I found a while paper from Juniper Networks called "Optimizing Broadband Service Delivery" that describes how DSL providers are switching their networks from ATM to Ethernet. The paper provides a good background on the network behind a DSL modem.