Blog of Leonid Mamchenkov

Most of today I spent in the Mediterranean hotel. Together with about twenty other administrators from most Cyprus ISPs, I attended DNS/DNSSEC course given by RIPE NCC.

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Most of the modern cell phones are equipped with both “Bluetooth” and “Infrared”. “Bluetooth” is extremely popular these days. But “Infrared” also has its use. The other day I was reminded of this.

My brother and I were in the car on the highway between Paphos and Limassol. I was driving at about 140 km/h. My brother was occupied copying ringtones from my SonyEricsson P800 onto his SonyEricsson P910. “Bluetooth” connection wasn’t working at all. When I slowed down to about 80 km/h it managed to connect, but was very slow and unstable. “Infrared” on the other hand, worked like a charm.

I suspect that this was because “Bluetooth” is a point-to-multipoint connection. Basically, it is like a small radio transmitter. It sends waves to about 10 meters around it. Because the car was moving so fast, it was getting out of the 10 meters radius pretty fast. “Infrared” on the other hand is a point-to-point connection. As long as it can “see” the other end, the connection will work perfectly.

MRTG (Multi Router Traffic Grapher) is monitoring utility, which runs on many platforms and is capable of collecting and graphing statistical information such as network traffic, CPU/Memory/Disk space usage, etc. MRTG can gather information using both SNMP protocol and external scripts. Below are few pieces of my MRTG config file together with scripts, which I felt like sharing.

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