Ten years ago, shortly after I started my first job as a network programmer at an Australian university, I received a call from a person working in one faculty who was having some network difficulties. All of their computers were connected together by 50-ohm coaxial cable ethernet, and two of the computers on this network sent a considerable amount of data to each other.
This data, naturally, was echoed along the entire network cable and was the primary cause of delays and packet loss to other users of the network. The caller wanted to know of a way to solve this problem. My manager suggested the use of a bridge; the two noisy computers could be placed behind this device and their traffic to each other would be confined to their segment. This solution was particularly attractive as it would not require any other changes to the network or the network numbering; it could be inserted and would work immediately.
For a number of years now, the Linux kernel has had the ability to turn any host with more than one network interface into a bridge. This article explains how it works.
Continue reading "Ethernet Bridges under Linux"