6 ms·

But for bandwidth can't you just have two simple computers at either end that can send a 100GB file and if it arrives in 20 seconds, you know you have 40gbps of

But for bandwidth can't you just have two simple computers at either end that can send a 100GB file and if it arrives in 20 seconds, you know you have 40gbps of bandwidth?

traceroute66 1mo ago
> But for bandwidth can't you just have two simple computers at either end that can send a 100GB file and if it arrives in 20 seconds, you know you have 40gbps of bandwidth? Because that is not reproducible and introduces all sorts of other random variables to your test. Expensive equipment is the only answer here. Its a bit like when you ask an electrician to install network cable (yuk !). They consider their job done after a continuity test (if they bother to do a continuity test at all). Meanwhile, if you put a Fluke on it, you will pick up all sorts of subtle faults that the electrician's continuity tester will never pick up, but will cause subtle and hard-to-diagnose problems when you try to push data over the cable. Its the same thing with all those cheap USB testers. They might have all sorts of fancy displays, but in the end they are no substitute for the real thing and will end up lulling you into a false sense of security.
- criddell 1mo ago
  If you buy decent cables from reputable companies (CableMatters, LTT, Apple, etc...) you could end up with a drawer full of high quality mystery cables. A cheap tester is probably all you really need to sort out that mess.
- chainingsolid 1mo ago
  You mention a Fluke, which I'm assuming is in relation to an ethernet cable tester (made by Fluke). I've seen/used continuity testers, but not something better (I've been using iperf3) Could you link/include the sku/model number of what you are refering too?
  - fragmede 1mo ago
    https://www.homedepot.com/pep/Fluke-Networks-LIQ-100-LinkIQ-Cable-Network-Tester-LIQ-100/335131563 https://www.homedepot.com/pep/Fluke-Networks-LIQ-100-LinkIQ-... Only $2,500!
    - traceroute66 1mo ago
      > Only $2,500! Actually no. That one is no good. The one I had in mind is the one that professional network cabling installers use. This one: https://www.cdw.com/product/fluke-dsx-cableanalyzer-dsx2-5000-network-tester-kit/5086508 https://www.cdw.com/product/fluke-dsx-cableanalyzer-dsx2-500... Only $13,000 :) Datasheet: https://www.flukenetworks.com/datacom-cabling/Versiv/dsx-cableanalyzer-series https://www.flukenetworks.com/datacom-cabling/Versiv/dsx-cab...
      - fragmede 1mo ago
        I didn't want to scare anyone off Your link 404's for me, here's it on Amazon. https://a.co/d/02K5Kdvy https://a.co/d/02K5Kdvy Note: not an affiliate link but if I had one I'd totally use it here ;)
    - chainingsolid 1mo ago
      That would explain why I haven't seen one! Thanks for the info.
rtkwe 1mo ago
You have to first identify and ensure the two devices and their ports are capable of reliably creating and absorbing that data rate too or you'll never know if it's the cable or the devices that causes the cables to fail. What if your devices can but only intermittently or a software/firmware update messes with it's capabilities? Dedicated test equipment that can reliably and verifiably test these high speeds is niche and therefor expensive. There's not really a way around that issue.

But for bandwidth can't you just have two simple computers at either end that can send a 100GB file and if it arrives in 20 seconds, you know you have 40gbps of bandwidth?

traceroute66 1mo ago

> But for bandwidth can't you just have two simple computers at either end that can send a 100GB file and if it arrives in 20 seconds, you know you have 40gbps of bandwidth? Because that is not reproducible and introduces all sorts of other random variables to your test. Expensive equipment is the only answer here. Its a bit like when you ask an electrician to install network cable (yuk !). They consider their job done after a continuity test (if they bother to do a continuity test at all). Meanwhile, if you put a Fluke on it, you will pick up all sorts of subtle faults that the electrician's continuity tester will never pick up, but will cause subtle and hard-to-diagnose problems when you try to push data over the cable. Its the same thing with all those cheap USB testers. They might have all sorts of fancy displays, but in the end they are no substitute for the real thing and will end up lulling you into a false sense of security.

criddell 1mo ago
If you buy decent cables from reputable companies (CableMatters, LTT, Apple, etc...) you could end up with a drawer full of high quality mystery cables. A cheap tester is probably all you really need to sort out that mess.
chainingsolid 1mo ago
You mention a Fluke, which I'm assuming is in relation to an ethernet cable tester (made by Fluke). I've seen/used continuity testers, but not something better (I've been using iperf3) Could you link/include the sku/model number of what you are refering too?
- fragmede 1mo ago
  https://www.homedepot.com/pep/Fluke-Networks-LIQ-100-LinkIQ-Cable-Network-Tester-LIQ-100/335131563 https://www.homedepot.com/pep/Fluke-Networks-LIQ-100-LinkIQ-... Only $2,500!
  - traceroute66 1mo ago
    > Only $2,500! Actually no. That one is no good. The one I had in mind is the one that professional network cabling installers use. This one: https://www.cdw.com/product/fluke-dsx-cableanalyzer-dsx2-5000-network-tester-kit/5086508 https://www.cdw.com/product/fluke-dsx-cableanalyzer-dsx2-500... Only $13,000 :) Datasheet: https://www.flukenetworks.com/datacom-cabling/Versiv/dsx-cableanalyzer-series https://www.flukenetworks.com/datacom-cabling/Versiv/dsx-cab...
    - fragmede 1mo ago
      I didn't want to scare anyone off Your link 404's for me, here's it on Amazon. https://a.co/d/02K5Kdvy https://a.co/d/02K5Kdvy Note: not an affiliate link but if I had one I'd totally use it here ;)
  - chainingsolid 1mo ago
    That would explain why I haven't seen one! Thanks for the info.

rtkwe 1mo ago

You have to first identify and ensure the two devices and their ports are capable of reliably creating and absorbing that data rate too or you'll never know if it's the cable or the devices that causes the cables to fail. What if your devices can but only intermittently or a software/firmware update messes with it's capabilities? Dedicated test equipment that can reliably and verifiably test these high speeds is niche and therefor expensive. There's not really a way around that issue.