Network discrimination simplified


Here’s a simplified write-up by Ed Felton on the topic of network discrimination.  I think this helps non-techies see why there would be a problem with the two-tiered internet so many big companies (baby bells, cable internet providers) want and why it would be bad for consumers.

Focus now on a single router. It has several incoming links on which packets arrive, and several outgoing links on which it can send packets. When a packet shows up on an incoming link, the router will figure out (by methods I won’t describe here) on which outgoing link the packet should be forwarded. If that outgoing link is free, the packet can be sent out on it immediately. But if the outgoing link is busy transmitting another packet, the newly arrived packet will have to wait — it will be “buffered” in the router’s memory, waiting its turn until the outgoing link is free.

Buffering lets the router deal with temporary surges in traffic. But if packets keep showing up faster than they can be sent out on some outgoing link, the number of buffered packets will grow and grow, and eventually the router will run out of buffer memory.

At that point, if one more packet shows up, the router has no choice but to discard a packet. It can discard the newly arriving packet, or it can make room for the new packet by discarding something else. But something has to be discarded.

Read the full article for a description of how this works out when considering high-priority versus low-priority traffic.

[tags]Network discrimination[/tags]