We run a medium sized afterschool computercafe for kids consisting of 24 computers. We have a problem we cant detect. When we update fortnite, windows updates, or other large updates, we set all machines to download. We then according to our ISP "max out" our network, a 100/100 connection. Then downloading huge updates, computers on our network seemingly disconnect from the internet. The broadband symbol in the tray turns to the yellow "warning sign", and internet access seems limeted.

We have some 100/100mbit switches, and a router supplyed by the ISP. We have had to guys from the ISP looking at our network but they have no explanation. Can you guys help us out, although we know its pretty vague information we give?


Router: cisco 890 series router

3 Switches: 24+2g-Port web smart gigabit ethernet switch (possibly d-link but unnamed)

best regards

  • You need to provide us more information. At least, a good description or diagram of the network, the network device models, and the network device configurations. You can read the Network Engineering Question Checklist for guidance, then edit your question. – Ron Maupin Sep 27 '18 at 15:20
  • You gave the router model, but we need the router configuration, and we need the switch models and configurations, and how they are connected. Speculation and guessing are off-topic here, and we need enough information to try to help with the network. – Ron Maupin Sep 27 '18 at 15:28
  • What are the device configurations? Show the configurations in your terminal, copy the configurations, and paste them into the question and use the Preformatted-text option ({}). – Ron Maupin Sep 27 '18 at 15:33
  • I cant figure out how to get the configurations, sorry – Potm Sep 27 '18 at 15:37
  • You log into the router, then show the configuration. It appears that your switches are off-topic here, and I really do not know how to do that for them. – Ron Maupin Sep 27 '18 at 15:38

Welcome to Network Engineering! We hope you will become a contributing member of this community.

Based on your (scant) information, you are very likely oversubscribing (i.e. "maxing out") your ISP connection, your router, or both. 24 computers all downloading at once only need to generate 4Mb of traffic to oversubscribe your link. Like an overcrowded highway, some cars can't move because there is too much traffic. The 890 router tends to top out at 15-20 Mbs, depending on which features are enabled, so that's also a bottleneck.

When data traffic can't get through, the computers time-out and assume the Internet connection is down (the yellow triangle).

You can upgrade the router and/or your ISP connection, but the simplest solution is to update your computers in batches (Maybe five at a time? You'll have to experiment), so you don't oversubscribe your link.

  • I do agree with the router or the line probably being maxed out, and the 890 series being geared towards the 25mbit/s-ish market. Yet, throughput achievable with an 88x or a 89x (older series, part number CISCO8xx) in the typical scenario with NAT overload might be more in the 60-80-something Mbit/s range. That would explain why it is hard to notice under everyday conditions. Newer C89x models should be able to chew the 100Mbit/s, with NAT and some rudimentary firewalling enabled, despite Cisco still putting them in the 25Mbit/s market. – Marc 'netztier' Luethi Sep 27 '18 at 20:18

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