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> ATM was the worst network protocol ever devised Having 53 byte payloads is something only a committee could love.
by gwright 3y ago
> ATM was the worst network protocol ever devised
Having 53 byte payloads is something only a committee could love.
- matthiasl 3y agoATM cells have 48 byte payloads. Supposedly that was because different groups involved in the standardisation process wanted either 32 or 64 byte payloads.
- chungy 3y agoThat's definitely a "split the baby down the middle" kind of solution.
- Paul-Craft 3y agoMore like a "fuck all you guys, I'm going home" kind of solution, if you ask me.
- drewolbrich 3y agoI think there's a similar story for the HDTV 16:9 aspect ratio.
- marcus0x62 3y agoSupposedly it was the largest size the French contingent to the standards committee would accept. They wanted a very small sample size to reduce the need for echo cancellation in their network.
- abwizz 3y agoconveniently about the size of a typical ip+tcp header
- p_l 3y agoStill better than 193 bit frames
- marcus0x62 3y agoI assume that’s a T1 dig? It worked quite well for the intended purpose - carrying voice traffic.
- p_l 3y agoSo did 53 byte frames, which was due to voice-specific requirements. Could it fit better? Sure. It was after all a compromise so equipment was interoperable.
- marcus0x62 3y agoThe 53 byte ATM cell was a compromise for a particular community of voice networks. And the overhead and small cell size never really worked "well" -- there are a bunch of reasons why Ethernet and IP won out, and low average overhead and the ability by the late 90s to scale switching and routing gear up to gigabit speeds and beyond were two big reasons. ATM collapsed under its own weight.
- InTheArena 3y agoyeah. 53 bytes was the total packet size, not the payload size. But oh hey! lets pick a large prime number for the number of bytes that a payload could be transmitted in. Lets also pick a small prime number of bytes so we can't do byte boundaries. Needless to say, I am glad that TCP/IP won. Moving on.
- NoZebra120vClip 3y agoFirst, ATM is OSI Layer 2, where PDUs are not called "packets", they are called "frames". ATM calls these frames "cells", so a cell is 53 octets (which literally means 8 bits, because guess what, not all bytes are that size.) ATM also covers Layer 1 (where PDUs are called "bits" or "symbols") and Layer 3 (where IP starts). Second, TCP/IP is Layer 3 and up, which means it runs on ATM just fine, like it runs on ISDN, Ethernet, Token Ring, PPP, and the various ITU standards for modems. ATM is commonly used in DSL implementations, so it also "won" as far as DSL has penetrated as a broadband technology.
- deleted 3y ago[deleted]
- kstrauser 3y agoAt least some telco types absolutely wanted to use ATM for everything. The idea was that instead of the completely anarchy of letting anyone connect to anyone else, you'd use ATM to build up sane, billable virtual circuits between endpoints. Basically, your computer would "call" a server, and Ma Bell would helpfully bill you for the connection and for the amount of data you passed. When you were done, you'd disconnect. I mean, it'd worked for years for voice, so why not data? Fortunately, that insanity lost.
- djbusby 3y agoUm. Is joke? Loads of cloud provider have billing related to the amount of data shipped. Freaking Route53 bills almost per query.
- benglish11 3y agoFor a meteorology focused response I don’t think the use of meteorological summer is too surprising. https://www.ncei.noaa.gov/news/meteorological-versus-astronomical-seasons https://www.ncei.noaa.gov/news/meteorological-versus-astrono...