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Fiber can also have asymmetrical speeds (see GPON, NGPON2 etc.). The issue is not the media per se but the concept of shared media. Take any media, wireless,
by zw123456 7y ago
Fiber can also have asymmetrical speeds (see GPON, NGPON2 etc.). The issue is not the media per se but the concept of shared media. Take any media, wireless, coax, fiber, even copper (ADSL) you have X amount of spectrum to work with so you have to decide how allocate said BW. Since most users demand is higher for downstream than upstream (typically you are downloading a lot more than uploading) it makes sense to allocate more to downstream. Of course it is possible to have full duplex symmetrical speeds. Say you want to allocate 2 fibers, on for upstream and one for downstream, then you can have symmetrical speeds. But typically due to costs, you want to have one fiber shared between a large number of users (e.g. GPON or NGPON, aka FiOS) or one coax shared amongst many users, or some set amount of RF spectrum, in any case you need to make the same type of trade off choice that the cable provider makes or that the DSL provider makes or wireless providers. In the case of wireless the reason that uplink is so much weaker is due to the limited power of the user equipment, also smaller antenna etc. refer to Shannon's law, uplink will be weaker. But generally speaking, it makes sense to have asymmetrical speeds unless you have the luxury of having the same spectrum and power available for both directions.
- wbl 7y agoDirectional couplers are a thing. Thomas Edison patented multiplexing techniques for telegraph wires that didn't even need them.
- jrockway 7y agoI think the fiber industry prefers wavelength division multiplexing over simple directional couplers. You can certainly have multiple 10Gbps customers on a single strand of fiber with passive equipment, and many ISPs will happily sell you such a circuit. (Gpon, mentioned above, is mostly time division multiplexing. I have worked for 2 ISPs that use gpon, and we've never sold anyone an asymmetric plan, except for the "free plan" that Google Fiber had. Gpon is perfectly happy to be symmetric, but it does have a limited bandwidth shared between multiple subscribers.) The biggest problem I've found is that the Internet isn't really ready for customers that can download at 10Gbps. When I set up a 10Gbps connection for myself, I had a lot of trouble finding anything on the Internet that would send me data that quickly. Even my own servers were AWS instance types that only supported 5Gbps burst. So that is probably the reason why you aren't seeing consumer ISPs selling you 10Gbps circuits... even the servers don't have 10Gbps! A new wave of upgrades are needed for this to become viable; 100Gbps networking equipment is still pretty expensive.
- Dylan16807 7y ago> The biggest problem I've found is that the Internet isn't really ready for customers that can download at 10Gbps. TCP is dumb and if it can saturate your connection it will increase your latency. I feel like being unable to saturate a connection is a good thing. There are other measures you can take to avoid saturation, but simply having an oversized pipe is hard to beat.
- jrockway 7y agoThis may be relevant to your interests: https://apenwarr.ca/log/?m=201808 https://apenwarr.ca/log/?m=201808
- Dylan16807 7y agoBut to really get best results, you need that management on both sides of a chokepoint, and you still want every other link in the system to be oversized. Fast links are a simple solution to a lot.
- TheCoelacanth 7y agoThe use case for faster connections isn't usually so that you can download faster from a single source. It's so that you, the spouse, three kids and the dog can each watch their own 4k stream while downloading software updates for six laptops, six phones, your fridge, your microwave and two dozen smart lightbulbs.
- navjack27 7y agoYeah I got FttH gigabit down 50 meg up for $65 here in upstate NY. It's the best in the area and it's a small company.