Ethernet The Occasional Outsider

coondoggie writes to mention an article at NetworkWorld about the outsider status of Ethernet in some high-speed data centers. From the article: "The latency of store-and-forward Ethernet technology is imperceptible for most LAN users -- in the low 100-millisec range. But in data centers, where CPUs may be sharing data in memory across different connected machines, the smallest hiccups can fail a process or botch data results. 'When you get into application-layer clustering, milliseconds of latency can have an impact on performance,' Garrison says. This forced many data center network designers to look beyond Ethernet for connectivity options."

Re:Lesson: Use appropriate Tech.

[Anonymous Coward]

I assume you mean "It's never been an efficient protocol." This is somewhat true, but relative to what, exactly? TDM? SONET? ATM?

If you did truly intend to state that it's not high speed, you're mistaken. 10 gigabit Ethernet is common, and modern hardware latencies are not significant. The only way you're going to exceed that would be with WDM (that's cheating) or with an OC-768 (good luck finding one outside of a research lab).

Re:Slashdot summary wrong, actual article is bette

[trollogic]

I think you have no clue about what your saying. 1) InfiniBand is an open standard hosted by IBTA which is a consortium of companies. The spec is available for anyone who wants to understand/build InfiniBand hardware. Not IEEE does not make it proprietary. 2) The major roadblock with 10Gbps is physics. You can only reach so far with copper without retiming the signal. And optics are expensive. 10 GbE has the same problem and it won't be cheap any time soon. 3) InfiniBand has already reached a volume where on-board IB chips are available in $70-80 range .. 10 GbE is no where close. And IB DDR will be shipping next month (20 Gbps wire / 16 Gbps data). 4) Beowulfs are popular for a reason .. Cache Coherency is a bitch. 5) A round trip node-to-node latency in IB is 2.7 usecs (best case of course). With all the optimization in the world, you won't be able to get ethernet anywhere near that number. 6) InfiniBand is being WIDELY deployed. Sandia Thunderbird is a 9216 processor IB fabric in production. NCSA has Tungsten2 which is 1024 processor IB fabric. NCSA also has a Microsoft Windows Cluster running CCE over IB with 880 processors. There are several large firms Oil&Gas, BioTech, Banks, Market Data houses which run several large multi-hundred/multi-thousand processor IB clusters. 7) Just as with any technology it will take time for new technologies to be accessible to the masses .. so don't write off anything yet. 8) Do you research before you open your mouth.