1990’s Internet

21 10 2011

Many years ago, when I migrated from dialup modem to cable the word broadband really did change your life. Always on, ping latencies below sub 500ms and ssh sessions that didnt resemble the teletype printer that used to broadcast the football results to the nation on Saturday at 5pm (for those that remember the 1970s). I was fortunate enough to be be in a rural UK village located between two nodes in what was then Cambridge Cables trunk network (later NTL, later Virgin). I was the first in this village to be connected, and I remember weeks of anticipation followed by dashed hopes as a stream of cable installation engineers visited. Eventually they admitted, that there was not enough signal getting to the door, and put in a slightly better quality cable. For almost 10 years after that, my Motorola Surfboard modem, connected to a UPS gave me broadband connectivity, 24x7x365 even through powercuts. Neve more than a few Mb/s but always on an always reliable sub 10ms latency with no packet loss.

Arriving in Sydney, in a 3G dark spot, I ordered up a Optus Cable connection and had a length of Coax strung from the nearest telegraph pole. It worked well at night and when the sun didnt shine. Over the past month thats been quite a lot. As soon as the sun shone the received power levels dropped below -10 dBmV and the the signal to noise ratio dropped below 35 dB. Packet loss started, DNS became horrible and the shiny 20Mb line became a 57K modem sitting in a microwave oven… if I was lucky. For fun, and to prove to Optus just how bad the connection was, I monitored the signal levels of the line with a script, the graphs are below. With power levels between -2 and +2 dBmV and signal to noise ratios about 40 dB if get solid connectivity. The rest of the time (power levels and SNR lower) all sorts of symptoms appear on the modem. In my case, on a day of about 27C with bright sun shine thats connectivity for about 1 minute every 5.

The Optus cable engineer arrived, looked at the graph, looked at the modem, looked at the telegraph pole, scratched his head and went up a ladder at the pole. 5 minutes later he came down with a 1997 Coax network tap. Corroded. Being at the end of the line, as in the UK village, I was the first to use the line (in years), and unfortunately GHz cant jump over a furred up connector.

For anyone with an awful net connection reading this post, and wondering if modem A or modem B will give them better performance, or if Optus is any better than Telstra, check you signal levels over time in sun and rain (refresh the page several times), you may have a corroded bit of the 1990s sitting between you and lighted fibre. If you do, the difference between 1Mb and 20Mb is probably irrelevant. Here are some keywords to help you find this post: Optus, Netgear CG3000, dropped, packets.




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