Re: pluggging Thunderbolt to network adapter into MacBook Air

[David Empson]

Michael Vilain <vil...@NOspamcop.net> wrote:

> I had a user come by yesterday with a network problem with his newish
> MacBook Air (a couple months old). He can use the local Wifi but can't
> connect via a wired connection through a network adapter into a
> Thunderbolt port.
>
> At his desk, we plugged in the adapter into either thunderbold ports and
> the Network Control panel status said neither ports were connected and
> there was no change in status when I moved the adapter from one port to
> the other.

Clarification needed: there is no MacBook Air which has two Thunderbolt
ports. The only Apple notebook models with two Thunderbolt ports are the
13" and 15" MacBook Pro with Retina Display.

Is that really a MacBook Air, or is it actually a MacBook Pro?

Is that really a Thunderbolt to Ethernet adapter, or a USB to Ethernet
adapter? (All recent MacBook Airs do have two USB ports.)

If it really is a MacBook Air and a Thunderbolt to Ethernet adapter, I'd
like to know which second port you were trying to plug it in to.

> Then we tried it at my desk using my PC's network cable.
>
> More and more, this is looking like a bad adapter. It isn't a very snug
> fit in either port but I didn't have spare to swap out for him. I
> suggested he take the laptop and adapter into an Apple Genius Bar and
> see if they can test it.
>
> To those out there with a wired line connected to a MacBook Air through
> the Thunderbolt port. If you move the adapter, does the status change
> (like a link light going on/off) in the Network system preferences?

I have a MacBook Pro (15-inch, Retina, Late 2013), which has two
Thunderbolt ports, plus an Apple Thunderbolt Ethernet adapter, running
OS X 10.9.3 (the major OS version may vary the details slightly, but the
Mac model shouldn't).

Without the adapter plugged in, I have a "Thunderbolt Ethernet" entry in
System Preferences > Network, which shows a red status marker. The text
description says "Status: Cable Unplugged. Either the cable or
Thunderbolt Ethernet is not plugged in or the device at the other end is
not responding." If I click on Advanced > Hardware, the MAC Address
field is blank.

Plugging in the adapter (with no Ethernet cable connected to it)
produces no visible change on the initial status page, but if I go to
Advanced > Hardware, the MAC address is now shown.

Plugging in an Ethernet cable (with nothing at the other end) changes
nothing.

With the other end of the Ethernet cable connected to a working network,
I get a green status indicator, IP address, etc.

Moving the adapter to my other Thunderbolt port, it takes a few seconds
for the status indicator to go green again (I didn't look at the MAC
address again, but I expect it would have appeared about the same time).

> I was guessing about the Adapter but we couldn't test further with the
> equipment we had on hand.
>
> Thanks in advance...



As a "for interest sake only" sidebar, I happened to see an option I
hadn't noticed before while looking at the Advanced > Hardware page: a
checkbox labelled "AVB/EAV mode", which is greyed out (and enabled)
unless the Ethernet adapter is set to manual configuration. A little
research suggests this indicates the Thunderbolt Ethernet adapter
supports an Ethernet Audio/Video Bridging protocol which I hadn't heard
about, which allows for prioritised real time delivery of audio and
video data over Ethernet, as long as all participating devices support
the protocol (endpoints and all intervening switches).

My previous MacBook Pro (Mid 2010) didn't have that checkbox, so either
Apple added it in later models (perhaps the 2011 series, coinciding with
Thunderbolt), or only in the Thunderbolt adapters, or it might be a new
feature in OS X 10.9 combined with certain hardware. I'd be interested
ot know if anyone with a 2011-2012 MacBook Pro with built-in Ethernet
port has that same checkbox.

The Thunderbolt Ethernet adapter also supports jumbo frames (9000
bytes).

For comparison, I also have a CalDigit Thunderbolt Station connected,
which has its own Ethernet port. That shows up in System Preferences >
Network as "Thunderbolt Ethernet Slot 1, Port 2" (which changes if I
plug it into a different Thunderbolt port). Its hardware page doesn't
show the AVB/EAV mode checkbox, and it doesn't offer jumbo frames when
manually configured.


--
David Empson
dem...@actrix.gen.nz

[bi...@mix.com]

David Empson <dem...@actrix.gen.nz> writes about AVB/EAB mode;

> My previous MacBook Pro (Mid 2010) didn't have that checkbox, so either
> Apple added it in later models (perhaps the 2011 series, coinciding with
> Thunderbolt), or only in the Thunderbolt adapters, or it might be a new
> feature in OS X 10.9 combined with certain hardware. I'd be interested
> ot know if anyone with a 2011-2012 MacBook Pro with built-in Ethernet
> port has that same checkbox.

It's available in the 2012 MacBook Pro. Here's a popular audio/video via
ethernet (udp) protocol that should be supporting it soon, or maybe already
is -

http://www.audinate.com/index.php?option=com_content&view=article&id=92

Billy Y..
--
sub #'9+1 ,r0 ; convert ascii byte
add #9.+1 ,r0 ; to an integer
bcc 20$ ; not a number

[David Empson]

Michael Vilain <vil...@NOspamcop.net> wrote:

> In article <1lnubh4.1gu8h75mpgi80N%dem...@actrix.gen.nz>,

> dem...@actrix.gen.nz (David Empson) wrote:
>
> > Michael Vilain <vil...@NOspamcop.net> wrote:
> >
> > > I had a user come by yesterday with a network problem with his newish
> > > MacBook Air (a couple months old). He can use the local Wifi but can't
> > > connect via a wired connection through a network adapter into a
> > > Thunderbolt port.
> > >
> > > At his desk, we plugged in the adapter into either thunderbold ports and
> > > the Network Control panel status said neither ports were connected and
> > > there was no change in status when I moved the adapter from one port to
> > > the other.
> >
> > Clarification needed: there is no MacBook Air which has two Thunderbolt
> > ports. The only Apple notebook models with two Thunderbolt ports are the
> > 13" and 15" MacBook Pro with Retina Display.

[...]

[...]

> I didn't check the model # in the "About this Mac" to note what it was,
> so I don't know what model it was really. I just know it's smaller than
> my 15" MacBook Pro and had 2 Thunderbolt ports and no optical disk. I
> know the difference between a Thunderbolt port and a USB port (the
> Thunderbolt port is smaller and thicker. My system has both.

OK, so it sounds like a 13" MacBook Pro with Retina Display. Must be
running at least OS X 10.8 (at least 10.9 if it is the Late 2013 model).

> The RJ45 port on the other end of the Thunderbolt network cable was
> plugged into an active ethernet port. I know it's active because I
> unplugged my laptop's ethernet cable and plugged it into this cable.
> Nothing happened on the Network System Preferences. No DHCP address
> detected. The text below the adapter on the left didn't change -- it
> said there was no network connection in either port.
>
> If I plug the Thunderbolt to DVI adapter into either Thunderbolt port, I
> get video on the 24" monitor, so the ports are working for video.
>
> I did as you described, switching the adapter with a known good ethernet
> connection between the two ports and neither worked or changed status.
> No lights. If there no adapter, I got the same message you quoted

> "Status: Cable Unplugged. Either the cable or Thunderbolt Ethernet is
> not plugged in or the device at the other end is not responding."

Did you click the Advanced button, click the Hardware tab and see
whether the MAC address appeared when the adapter was plugged in? That
is independent of whether there is anything connected to the RJ-45 port.

If the MAC address didn't appear, then the computer didn't detect the
Thunderbolt adapter was plugged in. Probably a fault on the Thunderbolt
side of the adapter. (Another place to check would be in About This Mac
> More Info > System Report > Thunderbolt.)

It could still be an internal fault with the Thunderbolt controller in
the computer, since the video adapter you plugged in is not a
"Thunderbolt to DVI adapter" but a "Mini-DisplayPort to DVI adapter".
That proved most of the pins on the port were OK, and the controller is
able to pass video, but it doesn't test whether the PCI Express lanes
are getting to the Thunderbolt ports (and that is what the Ethernet
adapter needs).

It could also be a software problem, such as the driver not loading, or
the network interface not being configured. There might be a similarly
named interface you were looking at: it should be called "Thunderbolt
Ethernet" in System Preferences > Network. I'm not sure whether the
interface is tied to a specific adapter - you might need to add another
interface if that isn't the same adapter which was previously used with
the computer. I haven't had access to two adapters to test this.

If the MAC address did appear but the network still didn't work, it
might be as simple as a fault in the RJ-45 socket on the adapter, but
could also be a different internal fault on the Ethernet side of the
adapter.

It is most likely that the adapter is broken.

> This is looking more and more like a bad cable. We can order it and it
> will come in a week later or he can take time on the weekend to have
> Apple check out his machine.


--
David Empson
dem...@actrix.gen.nz