Anybody tried IP over Thunderbolt 2 ?

Discussion in 'Mac Pro' started by Anim, Feb 10, 2014.

  1. Anim macrumors 6502a


    Dec 16, 2011
    Macclesfield, UK
    Noticed that Mavericks supports this and with the nMP coming this could allow fast mirroring of data between a laptop and the desktop using thunderbolt instead of going over the network.

    Has anybody tried this? is it really 20 x faster than say 1Gb ethernet?

  2. VirtualRain macrumors 603


    Aug 1, 2008
    Vancouver, BC
    I used a TB1 connection between my previous MBA and my new rMBP in target disk mode to migrate things, and it was smokin fast. I don't know exactly how fast, but I think the speeds of the SSDs were the limiting factor. Theoretically, it should be 10Gbps for TB1 and a full x4 PCIe v2 (2GB/s = 16Gbps) for TB2.
  3. Anim thread starter macrumors 6502a


    Dec 16, 2011
    Macclesfield, UK
    Interesting thanks.

    Found this article also on here where users try using a mac as a kind of Thunderbolt switch between 3 machines.

    One other user thought this maybe a good way to boost Compressor workloads because when you connect a machine via thunderbolt it appears as a network interface e.g. "en3" in system preferences (which I assume is different to target disk mode). So, if you have any other thunderbolt capable machine around you can connect it up to the nMP for slave rendering using a very fast connection.
  4. deconstruct60 macrumors 604

    Mar 10, 2009
    Target Disk Mode is vastly different. TDM puts the system into a state where it acts like a peripheral; not a host computer. The other Mac can just "drive" the disk like it was in an external drive enclosure.

    IP over Thunderbolt involves two active work arounds. First, that the two TB controllers are both in 'host computer' mode. Second, is emulating IP protocols over Thunderbolt. Mainly TCP.

    From reports here on macrumors and around the Internet it looks alot like this was some "Summer Intern" project that got weaved into the OS. It works in that can get data from one machine to another but is in no way optimized or mature. If people experiment with it and provide Apple feedback on making it better it would evolve over time. Otherwise it may fall into gimmick category over the long term.

    One problem appears that the emulation tells the rest of the network stack that it can to TCP offload work when in reality it can't offload that to hardware. The other part I suspect is interactions with Mavericks "race to sleep" which is in conflict with taking on a high amount of TCP overhead work (throw on top Apple's somewhat clueless thread scheduler and are asking for trouble).


    Here are some folks trying to make a DAS/SAN out of it.

    "Fast" isn't as big of an issue as "consistent" is. [ Although I don't really think DAS on both sides and pushing each way is really going to work well anyway. A server with two clients probably works more evenly ( or at least gives each OS instance at chance not to do completely stupid scheduling which I think is part of the consistency issue they are seeing. ) ]
  5. hollyhillbilly macrumors member

    Mar 30, 2012
    I posted this last week,
    Neil Smith of LumaForge is doing a great deal of testing.
    The youtube video is around 36 min.
    Look around the 30min when they do the testing with three computers IP over T2.

    The KEY is Neil stating that apple is working on the erratic behavior of Thunderbolt streaming media. Maybe a future update from Apple?

    However if you are only using to drag and drop files, it works incredible fast and reliable.

    "Neil Smith of LumaForge demonstrates the New Mac Pro, with speedtest across a shared environment(Two nMacPros and rMBP). With very interesting developments with IP over Thunderbolt in Mavericks(Thunderbridge)"

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