3 ms·
The bandwidth is much too low.
by fsh 3y ago
The bandwidth is much too low.
- londons_explore 3y agoIf this were true, then people would be running datacenter networking over HDMI. Data is data - there is no benefit to designing two entirely different transport mechanisms for video vs other data. You could argue that video data has a deadline to meet - but ethernet already has lots of mechanisms for QoS and bandwidth reservations to make sure that someones torrents don't interrupt something latency sensitive. Sure, they aren't widely supported over the internet, but between your PC and your display - they can be engineered to work properly.
- wmf 3y ago25 Gigabit Ethernet costs ~100x more than 32 Gigabit Displayport.
- aidenn0 3y agoSounds like the real question is why don't people use DP for p2p networking links...
- xienze 3y agoThere’s nothing magic about DP cables, they’re just typically a short-ish length, which is why they can be high bandwidth and relatively cheap. Once you get to a decent length, the cables get really expensive because you have to put optical transceivers on either side. I have a 25 foot DP cable which cost over $100, for example. So you could do a short length, high bandwidth Ethernet cable, I’m sure. But the reason we don’t is probably because differentiation between connectors is desired —- consumers are dumb, frankly. They’ll think any old Ethernet cable will work. Just look at what kind of a mess exists with USBC.
- ianburrell 3y agoThe commonality of connector is important. Ethernet has stopped using twisted pair cables for higher speeds. The SFP transceiver means can use short DAC copper cable or fiber optics for longer distances. The DAC cables that would compete with DisplayPort are pretty cheap. Also, a big portion of the cost of networking is in the switch that can handle high bandwidths. My guess is that 25G DisplayPort switch would be just as expensive as 25G SFP one.
- aidenn0 3y agoYeah, my original comment was based on the "100x more expensive" assertion. a 5m DAC cable is $40 on Amazon, and 25GBe cards can be had for under $200. I think it's probably more than $2.40 for just a 5m DP cable, so 100x was a gross exaggeration.
- wmf 3y agoIt's unidirectional and short reach.
- yellowapple 3y ago> If this were true, then people would be running datacenter networking over HDMI. Why would they? If they need more bandwidth than what Ethernet provides, they'd probably just bite the bullet and go with fiber. ...which punts the previous question to why the industry hasn't gone all-in with fiber optic display connectors, like it has with TOSLINK for S/PDIF in the audio world.
- zokier 3y agoEthernet over fiber is still ethernet.
- xxpor 3y agoTOSLINK/S/PDIF is way out of date and no one uses it any more. Ironically, because it doesn't have enough bandwidth for things like Atmos.
- ShadowBanThis01 3y agoNot entirely true. My house was built with an A/V closet that's not in the living room. To put analog equipment (like a turntable) in the living room where it's used, I convert the analog signals into digital with a $100 A/D converter that sends them over CAT-6 under the house to a decoder that connects to the receiver with Toslink. It works great, and I bought this in the last three years.
- xxpor 3y agoSure, for PCM stereo content it still works perfectly fine. Which is a lot of stuff! But it'd be a poor choice for 5.1 or better today.
- ShadowBanThis01 3y agoI was curious about that; because I couldn't be bothered to do the math myself, I looked up the max bitrate of multichannel PCM. Found this at https://www.videohelp.com/hd https://www.videohelp.com/hd : "Linear PCM up to 9 channels (Max 27.648 Mbit/s)" Cat5 or higher (especially only 20 feet) would easily handle that.
- FuriouslyAdrift 3y agoHDMI has been used for stacking ports for years... I think it's gone out of fashion, though. https://www.dell.com/support/kbdoc/en-us/000120108/how-to-stack-dell-networking-powerconnect-5500-model-switches https://www.dell.com/support/kbdoc/en-us/000120108/how-to-st...
- kevin_thibedeau 3y agoHDMI is severely length limited. Ethernet has no millisecond level latency guarantees. Data isn't always just data.
- mr_toad 3y agoBetter compression would surely help. The cloud gaming people are telling us they can deliver 4K 60fps video over 35Mbps.