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Thread: Windows Network Internet Slows to a halt at end of day!

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    Should Get Out More Greenman's Avatar
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    Default Windows Network Internet Slows to a halt at end of day!


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    Don't usually ask advise on here about work but this one is driving me mental.

    I have a network where at around 2pm every day the internet almost grounds to a halt.

    The speeds will all be fine for everyone for the rest of the day but come around 2pm it will slow massively, sometimes even timing out to websites.

    I have ran wireshark and nothing comes back untoward. I also get a really good result when speed testing on every switch in the school, hardly any jitter at all and my ping rates are pretty solid.

    I am about to replace an old 24 un-managed switch but apart from that i'm struggling. The LA as per normal does not want to know and say they can see no issues their end (i'm dubious as this has only happened after we signed a cluster of their schools).

    I can't see any issues but still the internet will be shit all afternoon every day. No scheduled tasks running at that time and according to Virgin (ISP) there should be ample bandwidth to serve the entire POP in the area.

    I am running a Server 2012 physical server that hosts a 2016 virtual server (Hyper V) on HP un-managed switches throughout, all updates etc installed last week.

    Any ideas what this could be before i resort to large hammers?

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    Should Get Out More Julian_Boolean's Avatar
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    Default Re: Windows Network Internet Slows to a halt at end of day!

    If it's on adsl, someone who is on the same D-SLAM is using all the bandwidth from 14:00

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    Should Get Out More Makman's Avatar
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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Someones bitcoin mining operation or porn connection is kicking in at that time every day. Also, check AV scan processes as they can serious slow things down.

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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Quote Originally Posted by Julian_Boolean View Post
    If it's on adsl, someone who is on the same D-SLAM is using all the bandwidth from 14:00
    That's gone straight over my head.

    What's D-SLAM.

    I'm not cisco man, just know the basics.

    LA control all routing etc router back, would you say this is an issue for them. Everything internally is fine al day, i can image a laptop at 5gb min, but go to load a page on t'internet and it just times out!

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    Should Get Out More Julian_Boolean's Avatar
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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Quote Originally Posted by Greenman View Post
    That's gone straight over my head.

    What's D-SLAM.

    I'm not cisco man, just know the basics.

    LA control all routing etc router back, would you say this is an issue for them. Everything internally is fine al day, i can image a laptop at 5gb min, but go to load a page on t'internet and it just times out!
    A D-SLAM (if they're still called that) is the equipment in the telephone exchange that the ADSL circuit connects to, these have multiple customers connected to them, all of those customers share the D-SLAMs bandwidth, the more you pay the less customers are connected to the D-SLAM

    So if someone else is using lots of bandwidth, you get none.

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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Quote Originally Posted by Julian_Boolean View Post
    A D-SLAM (if they're still called that) is the equipment in the telephone exchange that the ADSL circuit connects to, these have multiple customers connected to them, all of those customers share the D-SLAMs bandwidth, the more you pay the less customers are connected to the D-SLAM

    So if someone else is using lots of bandwidth, you get none.
    Hopefully the LA have something in place to stop this!

    As it happens it is starting to happen at another school too under the same LA.

    Coincidence, i think not.

    All they have in the schools is a Virgin home hub box giving 40mb, it's pretty poor tbh.

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    Should Get Out More Julian_Boolean's Avatar
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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Quote Originally Posted by Greenman View Post
    Hopefully the LA have something in place to stop this!

    As it happens it is starting to happen at another school too under the same LA.

    Coincidence, i think not.

    All they have in the schools is a Virgin home hub box giving 40mb, it's pretty poor tbh.
    Do they access the internet directly, or VPN back to a central site and all the internet go out through that central site, in which case the central site may be your problem.

    To test you should isolate the router from the rest of the network and perform a bandwidth test to something like Ookla, and then do the same with the rest of the network connected to the router, don't worry about the actual figure, you're looking at the comparison between the two tests - if both are the same your problem is beyond the router, if it is a lot lower with the network connected the problem is within that network.

    You'll want to do at least 10 bandwidth tests in each situation so that you can get an average of how it is behaving.

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    A Bit Bored phil1250's Avatar
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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Just a thought have you got a backup scheduled to kick in at that time over the network to a NAS.

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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Quote Originally Posted by Julian_Boolean View Post
    Do they access the internet directly, or VPN back to a central site and all the internet go out through that central site, in which case the central site may be your problem.

    To test you should isolate the router from the rest of the network and perform a bandwidth test to something like Ookla, and then do the same with the rest of the network connected to the router, don't worry about the actual figure, you're looking at the comparison between the two tests - if both are the same your problem is beyond the router, if it is a lot lower with the network connected the problem is within that network.

    You'll want to do at least 10 bandwidth tests in each situation so that you can get an average of how it is behaving.
    They access internet directly.

    I have tested as you say.

    I have isolated the router plugged a laptop into a port on the router with static IP and DNS, ran speed tests using LA's speed tester and it all comes back at around 43mb which is right.

    I then plug the uplinks back in to the other switches and was getting only 20mb. I found a dodgy cable and 2 hops down a possible dodgy switch, replaced both and all is now testing at 43ish meg on all switches isolated or not. I think i done about 3 tests on each using different ports on different modules to make sure it wasn't just a module on the switch failing.

    This is my issue, i cannot get the speeds to drop even running a continuous ping, it's completely solid with no drops in ping rate except maybe 1ms here and there. bbc.co.uk gives me solid 38ms pings, but if i then try and access the site at the same time on the same device it can take 20 seconds to load!

    No DNS errors in my event log, Nslookup resolves everything fine.

    When i tested with the LA manager we got the drop as mentioned above, but now i am getting no drop and it still slows at around 2pm, i'm thinking of going back to him and saying it must be a Router issue which they support, but he will ask for evidence and be as awkward as pos as he doesn't want to hassle.

    I've been supporting these networks for over 20 years and this is the strangest problem ever!

    I suspect it could still be the old switch i am about to replace (additional to the one above), but seems odd why it works fine at the start of the day!

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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Quote Originally Posted by phil1250 View Post
    Just a thought have you got a backup scheduled to kick in at that time over the network to a NAS.
    I thought this myself but no, they run at 6pm.

    Also with backups running it used to be fine anyway. The backups from local as the NAS box is located on the same switch as the server.

    Internal speeds are spot on, external is the issue...

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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Quote Originally Posted by Greenman View Post
    Hopefully the LA have something in place to stop this!

    As it happens it is starting to happen at another school too under the same LA.

    Coincidence, i think not.

    All they have in the schools is a Virgin home hub box giving 40mb, it's pretty poor tbh.

    FWIW I have had similar problems, again only towards the end of the day, in Citizens Advice which shares a LA network. No idea of the technical stuff on the network, but after about 3 pm we kept getting time-outs and 'no internet' errors on our database.

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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Quote Originally Posted by Greenman View Post
    They access internet directly.

    I have tested as you say.

    I have isolated the router plugged a laptop into a port on the router with static IP and DNS, ran speed tests using LA's speed tester and it all comes back at around 43mb which is right.

    I then plug the uplinks back in to the other switches and was getting only 20mb. I found a dodgy cable and 2 hops down a possible dodgy switch, replaced both and all is now testing at 43ish meg on all switches isolated or not. I think i done about 3 tests on each using different ports on different modules to make sure it wasn't just a module on the switch failing.

    This is my issue, i cannot get the speeds to drop even running a continuous ping, it's completely solid with no drops in ping rate except maybe 1ms here and there. bbc.co.uk gives me solid 38ms pings, but if i then try and access the site at the same time on the same device it can take 20 seconds to load!

    No DNS errors in my event log, Nslookup resolves everything fine.

    When i tested with the LA manager we got the drop as mentioned above, but now i am getting no drop and it still slows at around 2pm, i'm thinking of going back to him and saying it must be a Router issue which they support, but he will ask for evidence and be as awkward as pos as he doesn't want to hassle.

    I've been supporting these networks for over 20 years and this is the strangest problem ever!

    I suspect it could still be the old switch i am about to replace (additional to the one above), but seems odd why it works fine at the start of the day!
    Might be as simple as a component is heating up slowly, and at 2pm cannot handle it any more.

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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Have you tested while they're reporting slow running?

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    Default Re: Windows Network Internet Slows to a halt at end of day!

    You could also set your computer clock to 2 hours earlier, and do not let it synchronize, and see what time it happens on your watch, if 2 pm on your watch means it is something hardware related, and if it happens when it is showing 2pm on the computer clock will mean software related.

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    Default Re: Windows Network Internet Slows to a halt at end of day!

    Aaah, so that's what you lot do for a living then!

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