Doom and L4S

The DOOM video game was released on December 10th, 1993. It is now 30 years old. Doom is a first-person shooter that uses 3D graphics. From a networking viewpoint, its main characteristic was that it was designed as a multiplayer game. Several computers attached to the same Ethernet LAN could participate to the same game. At that time, game developers had limited networking expertise and the Doom developers opted for using IPX a proprietary networking protocol developed by Novell to exchange information about the position of the players in the game. Doom opted for using IPX broadcast frames to exchange this information, possibly assuming that all computers in the LAN would play Doom… This post provides Doom packets for the interested reader.

Unfortunately, some enterprise and universities used large IPX networks where broadcast packets had to be distributed to thousands of computers. This caused large networks to meltdown due to the amount of broadcast packets.

Additional information about Doom may be found in an article published for the 20th birthday.

For many years bandwidth has been a key metric for Internet access. Now that most technologies provide close or better than 100 Mbps, latency is becoming the metric that needs to be optimized. The IETF works on L4S: Low Latency Low Loss Scalable throughput to meet these objectives in terms of latency. They published the L4S architecture and several organizations have started to experiment with L4S. Mitchell Clark provides a nice introduction to L4S in a recent article published by The Verge.

This blog aims at encouraging students who read the open Computer Networking: Principles, Protocols and Practice ebook to explore new networking topics. You can follow this blog by subscribing to its RSS feed or by following @cnp3_ebook on mastodon.

Written on December 11, 2023