Part of that block diagram has me shaking my head. The downstream USB-C port, the one most likely to have another high speed device attached, is one of the ports that's connected to a hub on a hub for maximum data contention.
Or it could just be slightly lower than direct connection. I can't find many reviews of products using the RTS5423 but from what little I can find, it still manages close to 1GB/s speeds.
Right but there's two of em. Why isn't the hub-side Type C connected to the first one, like he asked? The first one has two USB-A's (3.1?), GbE LAN, and connects to the second RTS5423, which is further subdivided into audio, two more USB-A's, and the USB-C. Just a bit of a strange setup.
Right, but the question is why is the C port, the most likely one to use high bandwidth, hung off of the daisy chained hub rather than putting it on the first hub. Why not move one more of the A connections to the first hub so the C port can be higher up the chain?
I'd expect this to be the exact reason for placing the type-C on the end of the chain, so to speak: to avoid it hoarding bandwidth and thus starving other critical ports such as Ethernet. Besides, isn't the main point of a type-C hub to connect devices that aren't type C? How many non-portable type-C devices are there out there that require massive bandwidth and aren't TB3? And if it's portable, it makes more sense to connect it directly to the laptop than keep it connected to a dock, after all. It stands to reason that type-C is the least important port on such a dock for the foresebeale future.
> Besides, isn't the main point of a type-C hub to connect devices that aren't type C?
Problem is: Many devices are USB-C port starved, by connecting a dock in this weird configuration you're basically completely giving up on USB-C speeds. Even if you you don't use the the bandwidth the USB-C device will still be suffering...
But I guess the point of this USB-C port is an entirely different one: to allow for USB PD...
For me USB-C are interesting, especially having different USB-C laptops
1. Power Delivery varies and need option to turn off - if power delivery is not enough to power laptop 2. Compatibility between multiple laptops varies in the docks I found. Usually it best to go with maker of the laptop - but hopefully that changes 3. USB-C G2 is not as powerful as Thunderbolt 3 and not sure if it can handle daisy chain of USB-C devices like Thunderbolt 3
Well the typical cost is $100, I serious doubt it going that much difference. Especially if compatibility is there.
You can daisy chain USB hubs IIRC 7 layers deep. The potential gotcha is that not all the hubs in a chain are visible, eg some of the ports in this box are 2 chains deep not 1, sometimes a PC will have an onboard hub to get more ports. The latter was particularly common a few years ago when chipsets only had a handful of native ports a a 4 port hub was cheaper than a pair of 2 port controllers (in addition to the hub not eating PCIe lanes like the controller). Some devices will have a hub built in even though you wouldn't expect it, eg printers with card readers.
No matter what Thunderbolt 3 is significantly better than USB\-C Gen 2 - in fact it actually a super set of USB-C Gen 2 - It handles video better and once the controller on drives go better - it going to significantly better for storage. It also can handle external PCIe video cards.
I really hate proprietary standards, but you're right. USB has fallen behind, and for all it's improvements USB-C has become a cluster of features that a port may or may not support. A lot of that is due to legacy baggage. Rather than replacing USB entirely, I wish they had went with a complimentary "everything you need for a dock" industry standard port.
Something with PCIe, USB, audio, LAN, DP/HDMI, and enough juice to charge most laptops (anything high power like a gaming laptop would still require it's own power). A solution that would rely mostly on a device's existing chips, and thus the dock itself could be made simple/cheap. Docks with external graphics would be s bit more expensive, due to power delivery requirements, but you could still offer a kitchen-sink dock with graphics for less than we see today. Not to mention a non-proprietary standard.
Well Thunderbolt is no longer a propriety standard - yes was original joint venture between Apple and Intel - but specifications are now open. This standard based on USB-C and the standard has been open to other vendors. My guess is Apple was the one that was behind it be originally so propriety in the first place. Think about they created Lighting and older iPhone / iPad connectors
My XPS 15 2in1 has 2 thunderbolt 3 ports - I have a TB-16 dock - which was ok to power the XPS 13 2in1 with 180w - but I should have got to 240w adapter - but it ok - I use it primary for video and have the other port go to USB hub. Thunderbolt 3 can deliver power for gaming laptop.
"Rather than replacing USB entirely, I wish they had went with a complimentary "everything you need for a dock" industry standard port"
Thunderbolt 3 does not replace USB - this now open standard complements USB - fully compatible - the 2nd Thunderbolt 3 port mention about is being used as USB C - just because of the location - I have 2 other USB C ports - but normally not used.
Intel/Apple did a smart thing opening the standard - because it means other manufactures can make components for Thunderbolt 3 - thus bring prices down. I really would like a TB3 drive - but price is currently high - but with open standard I expect it to lower in the future.
I wasn't trying to imply thunderbolt replaced USB. I worded that poorly. I was trying to say that I understand why the USB-IF didn't replace USB, because they wanted backwards compatibility. But I wish they had come out with a second standardized connection type that handled this sort of scenario better and could directly pass through things like audio and ethernet without the need for external chips. Something even better than TB.
Thunderbolt is still not an open standard. What they DID do is drop royalties and share the specification. Eventually - they announced this in early 2017 but it didn't go into effect until roughly a year later. Anyway it's not an open standard, and Intel still fully controls it. They could very well do whatever they want with it in the future. If they really wanted it to be open, they'd have given it to the USB-IF or someone else. Of course, by adopting USB-C they've just made an already convoluted mess of a standard even messier. The list of USB-C functionality that each port may or may not support just keeps growing.
I also wouldn't blame Apple for the TB cluster, especially TB 2 and beyond. Intel sold TB controllers to other firms spanning back to at least 2013, it wasn't like they had an exclusivity agreement with Apple. If Intel wanted to spur adoption they could have done a number of things very differently.
What are the specs on the RTS5450? The block diagram calls it a mux and the label in the top left is DP1.4 + USB 3.1 gen2 so I assume this is relying on USB Alt mode for the video output which will limit compatibility over a USB display-link implementation. It also means that bandwidth will be split between the DP and USB 3.1 Gen2 either limiting USB and displayport to both to half their max speed or potentially full speed displayport and usb falling back to usb2 speeds.
This is exactly why USB 3 is such a mess. A single port USB-C dock is pretty cool idea but you really have no idea how well it will work with any random usb-c port of even if it will work at all.
The USB C port has dedicated pins/wires for USB 2 so you could dedicate all the high speed IO lanes to display port and fall back to USB 2 speeds for the USB assuming the dock was setup to support it. If you want USB 3 and Display port at the same time you'd end up splitting the lanes 50/50 so that you get USB 3 running at half speed so 5gbs for Gen 2 or 2.5gbs for gen 1 and Display port limited to lower resolutions. The alternative would be something like Thunderbolt or even displaylink where you aren't reassigning pins to different protocols but just transmitting the data so any bandwidth that isn't used by the display is available for USB data rather than the likely static 50/50 split for this hub.
Slight correction, USB 3.x Type-C cables support 4 high-speed signaling pairs in addition to the low-speed USB 2.0 pair. Both SuperSpeed USB 5 Gbps and 10 Gbps (USB 3.1 Gen1 and Gen2) only use 2 of the pairs (one for Tx one for Rx).
DisplayPort is normally implemented with a 4-lane main link. DP Alternate mode can either use all 4 high-speed pairs of a Type-C cable, limiting USB to the USB 2.0 low-speed pair, or operate on just 2 pairs, allowing full USB 3.1 Gen1/Gen2 bandwidth. With a DisplayPort 1.4 HBR3 capable host, even 2 lanes is still 12.96 Gbit/s of display bandwidth even after accounting for encoding overhead (enough for a 3840 x 2160, 60 Hz, 8 bpc stream).
USB 3.2 20 Gbps keeps the same 10 Gbit/s signaling rate of USB 3.1 Gen2, but uses all 4 lanes and implements channel-bonding. So DP alternate mode would limit the USB throughput in that case to USB 3.1 10 Gbps speeds.
The dock is meant to have all those ports conveniently there, but not to use it all in the same time. You can use a reasonable video resolution out and some audio streaming a movie via the network, you have all 3 available at moderate speed, not all at full capacity.
It's a real shame that they cannot amalgamate a lot of that functionality into a single chip, preferably without an internal USB hub chain unlike this design.
Input: USB 3.1 Rev1 or Rev2 (5 or 10 Gbps) Outputs: GigE, Audio, USB 3.1 x4 (Type A or Type C), Video from Alt-Mode
Also how does the Audio controller on that hub integrate with the HDMI output? Does it stream the audio digitally back to the host computer to put on the video output over USB Alt Mode?
How about using it with phones? Most have USB-C now and hopefully SoCs include the right outputs for data and video. WiDi or Miracast can't handle high resolutions and latency is a big issue.
Unfortunately, the USB-C connector in most phones and tablets support ony USB2 connection speeds instead of 3.0 or 3.1. I think it is a power issue in the implementation. But it is a shame that most cannot copy large files from PC at a decent speed. We had to resort to USB3 stick to copy video and large presentation across devices without a high-speed wireless link. Of course, we users want a way for large phones and tablets to be connected via USB-C and play hi-def video with sufficient voice controls to allow personal mobility around a house or conf room. But a myriad of devices are required making it very inconvenient. ChromeCast/Miracast tends to used but at best a mideocre solution and at times very unreliable. Why ise wireless if a cable can also charge the device and provide high-quality and low latency ?. We are not really given such choices by the manufacturers ....
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DanNeely - Monday, June 18, 2018 - link
Part of that block diagram has me shaking my head. The downstream USB-C port, the one most likely to have another high speed device attached, is one of the ports that's connected to a hub on a hub for maximum data contention.jordanclock - Monday, June 18, 2018 - link
Or it could just be slightly lower than direct connection. I can't find many reviews of products using the RTS5423 but from what little I can find, it still manages close to 1GB/s speeds.Alexvrb - Monday, June 18, 2018 - link
Right but there's two of em. Why isn't the hub-side Type C connected to the first one, like he asked? The first one has two USB-A's (3.1?), GbE LAN, and connects to the second RTS5423, which is further subdivided into audio, two more USB-A's, and the USB-C. Just a bit of a strange setup.eduardor2k - Tuesday, June 19, 2018 - link
It seems that each hub only supports 4 connections, that's why they need two of themwolrah - Tuesday, June 19, 2018 - link
Right, but the question is why is the C port, the most likely one to use high bandwidth, hung off of the daisy chained hub rather than putting it on the first hub. Why not move one more of the A connections to the first hub so the C port can be higher up the chain?wolrah - Tuesday, June 19, 2018 - link
Correction: "move one more of the A connections to the second hub"Valantar - Friday, June 22, 2018 - link
I'd expect this to be the exact reason for placing the type-C on the end of the chain, so to speak: to avoid it hoarding bandwidth and thus starving other critical ports such as Ethernet. Besides, isn't the main point of a type-C hub to connect devices that aren't type C? How many non-portable type-C devices are there out there that require massive bandwidth and aren't TB3? And if it's portable, it makes more sense to connect it directly to the laptop than keep it connected to a dock, after all. It stands to reason that type-C is the least important port on such a dock for the foresebeale future.Daniel Egger - Tuesday, July 3, 2018 - link
> Besides, isn't the main point of a type-C hub to connect devices that aren't type C?Problem is: Many devices are USB-C port starved, by connecting a dock in this weird configuration you're basically completely giving up on USB-C speeds. Even if you you don't use the the bandwidth the USB-C device will still be suffering...
But I guess the point of this USB-C port is an entirely different one: to allow for USB PD...
HStewart - Monday, June 18, 2018 - link
For me USB-C are interesting, especially having different USB-C laptops1. Power Delivery varies and need option to turn off - if power delivery is not enough to power laptop
2. Compatibility between multiple laptops varies in the docks I found. Usually it best to go with maker of the laptop - but hopefully that changes
3. USB-C G2 is not as powerful as Thunderbolt 3 and not sure if it can handle daisy chain of USB-C devices like Thunderbolt 3
Well the typical cost is $100, I serious doubt it going that much difference. Especially if compatibility is there.
DanNeely - Monday, June 18, 2018 - link
You can daisy chain USB hubs IIRC 7 layers deep. The potential gotcha is that not all the hubs in a chain are visible, eg some of the ports in this box are 2 chains deep not 1, sometimes a PC will have an onboard hub to get more ports. The latter was particularly common a few years ago when chipsets only had a handful of native ports a a 4 port hub was cheaper than a pair of 2 port controllers (in addition to the hub not eating PCIe lanes like the controller). Some devices will have a hub built in even though you wouldn't expect it, eg printers with card readers.HStewart - Monday, June 18, 2018 - link
No matter what Thunderbolt 3 is significantly better than USB\-C Gen 2 - in fact it actually a super set of USB-C Gen 2 - It handles video better and once the controller on drives go better - it going to significantly better for storage. It also can handle external PCIe video cards.Alexvrb - Monday, June 18, 2018 - link
I really hate proprietary standards, but you're right. USB has fallen behind, and for all it's improvements USB-C has become a cluster of features that a port may or may not support. A lot of that is due to legacy baggage. Rather than replacing USB entirely, I wish they had went with a complimentary "everything you need for a dock" industry standard port.Something with PCIe, USB, audio, LAN, DP/HDMI, and enough juice to charge most laptops (anything high power like a gaming laptop would still require it's own power). A solution that would rely mostly on a device's existing chips, and thus the dock itself could be made simple/cheap. Docks with external graphics would be s bit more expensive, due to power delivery requirements, but you could still offer a kitchen-sink dock with graphics for less than we see today. Not to mention a non-proprietary standard.
Pipedream, I know.
HStewart - Tuesday, June 19, 2018 - link
"I really hate proprietary standards"Well Thunderbolt is no longer a propriety standard - yes was original joint venture between Apple and Intel - but specifications are now open. This standard based on USB-C and the standard has been open to other vendors. My guess is Apple was the one that was behind it be originally so propriety in the first place. Think about they created Lighting and older iPhone / iPad connectors
My XPS 15 2in1 has 2 thunderbolt 3 ports - I have a TB-16 dock - which was ok to power the XPS 13 2in1 with 180w - but I should have got to 240w adapter - but it ok - I use it primary for video and have the other port go to USB hub. Thunderbolt 3 can deliver power for gaming laptop.
"Rather than replacing USB entirely, I wish they had went with a complimentary "everything you need for a dock" industry standard port"
Thunderbolt 3 does not replace USB - this now open standard complements USB - fully compatible - the 2nd Thunderbolt 3 port mention about is being used as USB C - just because of the location - I have 2 other USB C ports - but normally not used.
Intel/Apple did a smart thing opening the standard - because it means other manufactures can make components for Thunderbolt 3 - thus bring prices down. I really would like a TB3 drive - but price is currently high - but with open standard I expect it to lower in the future.
Alexvrb - Wednesday, June 20, 2018 - link
I wasn't trying to imply thunderbolt replaced USB. I worded that poorly. I was trying to say that I understand why the USB-IF didn't replace USB, because they wanted backwards compatibility. But I wish they had come out with a second standardized connection type that handled this sort of scenario better and could directly pass through things like audio and ethernet without the need for external chips. Something even better than TB.Thunderbolt is still not an open standard. What they DID do is drop royalties and share the specification. Eventually - they announced this in early 2017 but it didn't go into effect until roughly a year later. Anyway it's not an open standard, and Intel still fully controls it. They could very well do whatever they want with it in the future. If they really wanted it to be open, they'd have given it to the USB-IF or someone else. Of course, by adopting USB-C they've just made an already convoluted mess of a standard even messier. The list of USB-C functionality that each port may or may not support just keeps growing.
I also wouldn't blame Apple for the TB cluster, especially TB 2 and beyond. Intel sold TB controllers to other firms spanning back to at least 2013, it wasn't like they had an exclusivity agreement with Apple. If Intel wanted to spur adoption they could have done a number of things very differently.
kpb321 - Monday, June 18, 2018 - link
What are the specs on the RTS5450?The block diagram calls it a mux and the label in the top left is DP1.4 + USB 3.1 gen2 so I assume this is relying on USB Alt mode for the video output which will limit compatibility over a USB display-link implementation. It also means that bandwidth will be split between the DP and USB 3.1 Gen2 either limiting USB and displayport to both to half their max speed or potentially full speed displayport and usb falling back to usb2 speeds.
This is exactly why USB 3 is such a mess. A single port USB-C dock is pretty cool idea but you really have no idea how well it will work with any random usb-c port of even if it will work at all.
rpg1966 - Monday, June 18, 2018 - link
I might be missing something, but... of course bandwidth will be split, how can it not be?kpb321 - Monday, June 18, 2018 - link
The USB C port has dedicated pins/wires for USB 2 so you could dedicate all the high speed IO lanes to display port and fall back to USB 2 speeds for the USB assuming the dock was setup to support it. If you want USB 3 and Display port at the same time you'd end up splitting the lanes 50/50 so that you get USB 3 running at half speed so 5gbs for Gen 2 or 2.5gbs for gen 1 and Display port limited to lower resolutions. The alternative would be something like Thunderbolt or even displaylink where you aren't reassigning pins to different protocols but just transmitting the data so any bandwidth that isn't used by the display is available for USB data rather than the likely static 50/50 split for this hub.rpg1966 - Monday, June 18, 2018 - link
Thank you. I get what you mean, although AdrianB1's reply probably covers the use cases for the vast majority of people.repoman27 - Tuesday, June 19, 2018 - link
Slight correction, USB 3.x Type-C cables support 4 high-speed signaling pairs in addition to the low-speed USB 2.0 pair. Both SuperSpeed USB 5 Gbps and 10 Gbps (USB 3.1 Gen1 and Gen2) only use 2 of the pairs (one for Tx one for Rx).DisplayPort is normally implemented with a 4-lane main link. DP Alternate mode can either use all 4 high-speed pairs of a Type-C cable, limiting USB to the USB 2.0 low-speed pair, or operate on just 2 pairs, allowing full USB 3.1 Gen1/Gen2 bandwidth. With a DisplayPort 1.4 HBR3 capable host, even 2 lanes is still 12.96 Gbit/s of display bandwidth even after accounting for encoding overhead (enough for a 3840 x 2160, 60 Hz, 8 bpc stream).
USB 3.2 20 Gbps keeps the same 10 Gbit/s signaling rate of USB 3.1 Gen2, but uses all 4 lanes and implements channel-bonding. So DP alternate mode would limit the USB throughput in that case to USB 3.1 10 Gbps speeds.
AdrianB1 - Monday, June 18, 2018 - link
The dock is meant to have all those ports conveniently there, but not to use it all in the same time. You can use a reasonable video resolution out and some audio streaming a movie via the network, you have all 3 available at moderate speed, not all at full capacity.psychobriggsy - Tuesday, June 19, 2018 - link
It's a real shame that they cannot amalgamate a lot of that functionality into a single chip, preferably without an internal USB hub chain unlike this design.Input: USB 3.1 Rev1 or Rev2 (5 or 10 Gbps)
Outputs: GigE, Audio, USB 3.1 x4 (Type A or Type C), Video from Alt-Mode
Also how does the Audio controller on that hub integrate with the HDMI output? Does it stream the audio digitally back to the host computer to put on the video output over USB Alt Mode?
serendip - Tuesday, June 19, 2018 - link
How about using it with phones? Most have USB-C now and hopefully SoCs include the right outputs for data and video. WiDi or Miracast can't handle high resolutions and latency is a big issue.fteoath64 - Wednesday, June 20, 2018 - link
Unfortunately, the USB-C connector in most phones and tablets support ony USB2 connection speeds instead of 3.0 or 3.1. I think it is a power issue in the implementation. But it is a shame that most cannot copy large files from PC at a decent speed. We had to resort to USB3 stick to copy video and large presentation across devices without a high-speed wireless link.Of course, we users want a way for large phones and tablets to be connected via USB-C and play hi-def video with sufficient voice controls to allow personal mobility around a house or conf room. But a myriad of devices are required making it very inconvenient. ChromeCast/Miracast tends to used but at best a mideocre solution and at times very unreliable. Why ise wireless if a cable can also charge the device and provide high-quality and low latency ?. We are not really given such choices by the manufacturers ....