6 ms·

Why is 6 not useful and why is 5E/6A better?

ixf 8y ago
6 is useful for non-dense high-bandwidth environments where you might need to get 10G-BASET a little further than 5e will manage, but 6 doesn't address enhanced alien crosstalk. This means in dense environments it may struggle. 6A does, via shielding, and so will work better in dense environments (where you're likely to see 10G-BT anyway).
- Dylan16807 8y ago
  Shielding's optional for 6A so be careful where you buy if you want that.
- mcv 8y ago
  Isn't shielding separate from the category? I recall seeing stuff like Cat5 FTP and Cat6 STP or some combination like that. I'm no cable expert, but from what I understand, STP means shielded and FTP has some other kind of shielding. I think I put Cat6 STP or FTP in my home. Whichever it was, I wanted to have the best cable I could possibly find, because I don't want to have to redo this every 10 years.
GordonS 8y ago
If for no other reason, price - why pay more for something that's not any better than 5e?
- apple4ever 8y ago
  I've always found 6 cheaper than 5e, or at least the same price. And why not give myself some extra headroom?
  - GordonS 8y ago
    Firstly, I should have been clearer that I specifically meant cat6a, rather than cat6. I haven't actually bought an ethernet cable for several years now, but cat6a always used to be quite a bit more expensive than cat5e. I just had a quick look, and here in the UK it seems it still is, at least for shielded cables: - 30m UTP cat5e cable is £12 - 30m STP cat5e cable is £47 - 30m UTP cat6 cable is £14 - 30m STP cat6a cable is £100
StillBored 8y ago
Its not that 5E is better, its about the application. Either you need near full length runs of 6A for 10G, and you need to have it carefully terminated (which is a large problem in a lot of installs, more so than the actual cable) or you have short runs which will work just as well over just about anything that isn't completely screwed up. Maybe another way to put it is this: doing a poor CAT6 install (as this article points out most are) isn't buying you anything over cat 5E, your spending money for nothing.
- ccostes 8y ago
  How long is "long" in this context? 5ft? 50ft?
  - chx 8y ago
    10GBASE-T over Cat 5e works pretty well up to 100 ft and 150 ft is doable if you carefully run avoiding electronic noise sources (like a wall power outlet). NBASE-T IMO is much more interesting for end users because by now USB adapters for those should be out and I fully expect them any week to drop. 5gbit/s runs up to 300 ft on Cat 5E. Also, while five gigabit is certainly doable for laptops with NVMe disks (last three years, since Skylake), ten gigabit is not necessarily so if you have PCIe 3.0 x2 (or equivalent) bottlenecks here and there. See, many Intel U chip laptops run the on chip bus between PCH and CPU at only a PCIe 3.0 x2 equivalent speed (aka 16 gbit/s) and the U chips provide PCIe lanes only off the PCH so if your data streams needs to cross into the CPU and if you are burning 10 out of the 16 for just Ethernet, not a lot will be left. And most of the time you need to cross the On Package Interconnect because the system memory hangs off the CPU side of it and all the peripherals the PCH side of it (northbridge vs southbridge, to use older terms). There's no such problem with 5gbit/s, you can even put twice of that on a 2GT/s OPI and still have bandwidth to spare. Another potential such bandwidth choking point is the Thunderbolt controller, althought that might be past by now, because there is no JHL 7240 or Titan Ridge LP -- there was an Alpine Ridge LP which only used a PCI 3.0 x2 connection to the host meaning if you wanted to have a 5gbit/s USB A connection on your dock and you wanted 10 gbit/s Ethernet, you are already hitting all the constraints. Once again, 5gbit/s eases this problem. In about five years when PCIe 4.0 and USB 3.2 are ubiquitous, well established features in laptops, that's when we can begin to discuss whether ten gigabit makes sense at home/small office.

ixf 8y ago

6 is useful for non-dense high-bandwidth environments where you might need to get 10G-BASET a little further than 5e will manage, but 6 doesn't address enhanced alien crosstalk. This means in dense environments it may struggle. 6A does, via shielding, and so will work better in dense environments (where you're likely to see 10G-BT anyway).

Dylan16807 8y ago
Shielding's optional for 6A so be careful where you buy if you want that.
mcv 8y ago
Isn't shielding separate from the category? I recall seeing stuff like Cat5 FTP and Cat6 STP or some combination like that. I'm no cable expert, but from what I understand, STP means shielded and FTP has some other kind of shielding. I think I put Cat6 STP or FTP in my home. Whichever it was, I wanted to have the best cable I could possibly find, because I don't want to have to redo this every 10 years.

GordonS 8y ago

If for no other reason, price - why pay more for something that's not any better than 5e?

apple4ever 8y ago
I've always found 6 cheaper than 5e, or at least the same price. And why not give myself some extra headroom?
- GordonS 8y ago
  Firstly, I should have been clearer that I specifically meant cat6a, rather than cat6. I haven't actually bought an ethernet cable for several years now, but cat6a always used to be quite a bit more expensive than cat5e. I just had a quick look, and here in the UK it seems it still is, at least for shielded cables: - 30m UTP cat5e cable is £12 - 30m STP cat5e cable is £47 - 30m UTP cat6 cable is £14 - 30m STP cat6a cable is £100

StillBored 8y ago

Its not that 5E is better, its about the application. Either you need near full length runs of 6A for 10G, and you need to have it carefully terminated (which is a large problem in a lot of installs, more so than the actual cable) or you have short runs which will work just as well over just about anything that isn't completely screwed up. Maybe another way to put it is this: doing a poor CAT6 install (as this article points out most are) isn't buying you anything over cat 5E, your spending money for nothing.

ccostes 8y ago
How long is "long" in this context? 5ft? 50ft?
- chx 8y ago
  10GBASE-T over Cat 5e works pretty well up to 100 ft and 150 ft is doable if you carefully run avoiding electronic noise sources (like a wall power outlet). NBASE-T IMO is much more interesting for end users because by now USB adapters for those should be out and I fully expect them any week to drop. 5gbit/s runs up to 300 ft on Cat 5E. Also, while five gigabit is certainly doable for laptops with NVMe disks (last three years, since Skylake), ten gigabit is not necessarily so if you have PCIe 3.0 x2 (or equivalent) bottlenecks here and there. See, many Intel U chip laptops run the on chip bus between PCH and CPU at only a PCIe 3.0 x2 equivalent speed (aka 16 gbit/s) and the U chips provide PCIe lanes only off the PCH so if your data streams needs to cross into the CPU and if you are burning 10 out of the 16 for just Ethernet, not a lot will be left. And most of the time you need to cross the On Package Interconnect because the system memory hangs off the CPU side of it and all the peripherals the PCH side of it (northbridge vs southbridge, to use older terms). There's no such problem with 5gbit/s, you can even put twice of that on a 2GT/s OPI and still have bandwidth to spare. Another potential such bandwidth choking point is the Thunderbolt controller, althought that might be past by now, because there is no JHL 7240 or Titan Ridge LP -- there was an Alpine Ridge LP which only used a PCI 3.0 x2 connection to the host meaning if you wanted to have a 5gbit/s USB A connection on your dock and you wanted 10 gbit/s Ethernet, you are already hitting all the constraints. Once again, 5gbit/s eases this problem. In about five years when PCIe 4.0 and USB 3.2 are ubiquitous, well established features in laptops, that's when we can begin to discuss whether ten gigabit makes sense at home/small office.