On 9 June 2015 at 09:42, Martijn Koster mak-alug@greenhills.co.uk wrote:
There are hardware cable checkers, but they're either cheap (~£20) and check just continuity and wire map faults, or can test performance but cost hundreds of pounds like the Fluke ones.
Indeed, and I have the former...
You say it's an outside cable... did you terminate it yourself?
Yes I did. I will reterminate, although it's not really a strength of mine and I'm as likely to get it wrong this time as last time....
Are there any connection points, or damage to the cable
No, not that I can see anyway.
You could also look at the PSU that comes with your switch and router; sometimes they start providing borderline power.
As it happens it's a new switch, and the problem was there before and after changing it.
Are both ends connected to equipment plugged into the same power supply?
As in mains phase? Yes if so.
The easiest is probably to temporarily relocate the PC next to the router, use a different, shop-bought known-good cable, and compare.
Stupidly, I had thought about swapping cables but ruled it out on the basis that the length was too great, and had forgotten that the PC can be moved....
What is it specifically that is slow? It could be a network software issue.
There isn't a "specifically" - it seems to be pretty much everything. It's a quad-core CPU with 24GB RAM, and typically has one Virtualbox VM running and Chrome with a billion (ish :-) tabs open. At any given point htop shows CPU and memory usage to be fine (no swap in use, and the swap is on SSD anyway so shouldn't be such a hit anyway). I have a Virgin cable connection giving me 100Mbps to play with and if I do a speed test that gives me typically 85Mbps down, 5Mpbs up (which is about right for a Virgin connection) so throughput isn't a problem. Yet my desktop in the office, doing similar things on lower spec hardware and maybe 5Mbps ADSL on a good day, performs better. Note that for all the Chrome tabs and VM very little actual network activity will be taking place, although it won't be non-zero. Can a dodgy cable cause hardware interrupts (and if it can, can I detect them?). It *feels* like something is interrupting the CPU and I've pretty much ruled out all the local PC hardware by replacing it..
Additionally: I've had issues with the Virgin router just locking up and needing rebooting, or locking up on the cabled ethernet side but being fine on wireless. When I put a cable router in between the Virgin box and my home network, this issue seems to then start to affect the cable router. That's what made me start looking at the network initially.
Mark