IEEE Globecom postmortem

Ulrich Speidel attended IEEE Globecom in Abu Dhabi in December 2018 to present a IEEE Globecom 2018 paper on bufferbloat vs. TCP queue oscillation in satellite links on the wisdom of using buffers in the order of magnitude of the bandwidth-delay product on shared satellite Internet links, a topic already discussed here and here. The paper used data from the simulator to demonstrate that buffers dimensioned the conventional way are prone to large standing queues, which add latency for everyone but don’t act as shock absorbers. This practice was shown to have the same effect on Internet routers a long time ago and is no longer seen as best practice on terrestrial router buffers, but has continued unabated in the satellite industry – ironically the corner of the Internet with the highest inherent latencies and the most expensive bandwidth resource.

As is usual on events such as these, one gets to talk to people afterwards. In this case, I was approached by a very senior and well respected colleague from industry (VP Technology of a major satellite network provider serving direct to site end customers in the Americas). He told me that the paper had just solved a technical mystery for him – they were seeing the same added latency effects on some of their client site to network uplinks and couldn’t figure out why this was happening for some clients but not others. Well they do now, and I hope their clients (probaly primarily those sharing their connections locally) are enjoying better performance already.

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