[802.3_DIALOG] USB-C Ethernet Alternate Mode

[Michael Johas Teener <Mikejt@xxxxxxxxxxxx>]

(sorry about sending this so late … I sent this to the 802.1 reflector during the Berlin meetings, on March 9, and *tried* to send it to 802.3, but was using an incorrect email address. So, trying again … )

In the past few years  I’ve been investigating ways to replace the RJ-45 we all know and dislike (some of you may have heard of “Nu45”), and in the past few months i’ve decided that the most promising approach is to use the new USB type C. We can do this because USB type C is a *system*, not just a connector, and there are simple ways to have the connection use the 4 signal pairs that define the high speed paths in alternate ways. Originally I thought it was just a USB 3.x thing, but it turns out that Apple (among others)  will repurpose the connection to also carry DisplayPort (and through that, VGA and HDMI). It will be equally easy (maybe easier) to provide an Ethernet alternate mode.  The appropriate docs are available for free on the USB-IF website by downloading the [Universal Serial Bus Revision 3.1 Specification] … this is a zip file with seven major sections, with only the last one of interest.

By now, most of you have seen the news about the USB-C connector system being used in the new Apple Macbook), so this is a real thing, and it’s a big deal. The USB-IF, the group that controls the USB-C system, has indicated willingness to work with any group that does a good job defining how those signals are used in various “alternate modes". I have proposed to them that *someone* does this project for Ethernet.

To keep things simple, I have proposed that we start with using the USB3.1 PHY *as is* and just hook the Ethernet MAC to it … but to note that we would be proposing a *much faster* PHY as part of a future backwards compatible upgrade.

I’m not sure which group should really do this, but I may be proposing a CFI for 802.3 on this subject for the near future, and I’m looking for partners in this project.

Please contact me directly … I will be setting up a temporary public discussion and documentation area, and it will be completely open for all participants, although I will only be advertising it to the 802 community for the time being.

No matter what happens, I will keep the 802 community informed. This is not a single person, single company, or even single WG project, it’s a system … it’s something that should *finally* enable the “Ethernet Everywhere”  concept that’s been around for a long, long time.

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Michael Johas Teener - Sr. Technical Director, Broadcom Corp

mikejt@xxxxxxxxxxxx / m@xxxxxx - +1-831-824-4228