It always amuses me when I watch shows of would-be escape-artists who skillfully avoid detection by security guards or manhunters with the arcane distraction technique of rock throwing. Such preoccupation with little disturbance objects almost makes me want to wear figure-hugging black leather catsuits and go on burglary adventures too.
The past week though, I was that incompetent security guard.
Some people familiar with my information foraging habits know that I regularly connect back to my home computers - the nerve centre of communication with the communities around the world. A 10Mbps plan from SingNet fuels the information needs of my family, but naturally I use the lion's share of the bandwidth. Unfortunately, unlike just a couple of weeks back, my connection was stuck at a pathetic 3-4Mbps rating; everything downloaded at drastically reduced speeds, and remoting from office was a painful flipping-tile game experience. It was simply impossible to get enough visual refresh to get the information I needed, and the situation only worsened as the days went by.
I have experienced many QoS incidents with SingNet before, but none as pronounced and prolonged as this time. I eventually sounded alarm in Hardware Zone to see if other 10Mbps subscribers might have experienced similar problems. TCP/IP over telephony is obviously not an area of expertise for me, so I did not know what to make of the DSL modem's data until a fellow member asked me to paste the details over:
DSL Connection Details
DSL Line (Wire Pair): Line 1 (inner pair)
Protocol: G.DMT2 Annex A
Downstream Rate: 3961 kbps
Upstream Rate: 496 kbps
Channel: Fast
Current Noise Margin: 4.0 dB (Downstream), 5.4 db (Upstream)
Current Attenuation: 39.8 dB (Downstream), 45.6 db (Upstream)
Current Output Power: 19.4 dB (Downstream), 12.1 db (Upstream)
DSLAM Vendor Information: Country: {0xFF} Vendor: {GSPN} Specific: {0x1000}
PVC Info: 0/100
I did not know what "Current Attenuation" referred to when I pasted it and failed to realise the significance of those values. It was only due to my decision to move to all phone sockets around the house for microfilter inspection that I chance upon one of two well-hidden factors. When checking the microfilter next to the modem, I accidentally disconnected the phone cable used by the modem itself. So I fitted the phone jack back into the socket, and saw
DSL Connection Details
DSL Line (Wire Pair): Line 1 (inner pair)
Protocol: G.DMT2+ Annex A
Downstream Rate: 13996 kbps
Upstream Rate: 1088 kbps
Channel: Fast
Current Noise Margin: 19.0 dB (Downstream), 6.5 db (Upstream)
Current Attenuation: 12.5 dB (Downstream), 4.7 db (Upstream)
Current Output Power: 10.0 dB (Downstream), 11.3 db (Upstream)
DSLAM Vendor Information: Country: {0xFF} Vendor: {GSPN} Specific: {0x1000}
PVC Info: 0/100
A plug-out-plug-in activity solved the exceeding loss of sound energy in the cable. Yup.
So I got back my speedy DSL connection, but I noticed downloads were still sub-optimal, maxing out around 40KB/sec. It turned out the second of the well-hidden factor was µTorrent was spending 96KB/sec uploading - approximately 80% of the upstream bandwidth. When I reverted it back to my original setting of 33KB/sec, the download ratings rocketed to their expected limits.
A software setting that adjusted itself, against what I had previously configured? Yup.
Maybe somebody has been remote-hacking my BitTorrent client to put my network under DOS, as well as to loosen my phone cable.