Network broadcast storm - is it that easy to cause?

[simpsonj]

I'm going to show have much I am not a Network person here! As I understand it, we have a router which may have minimal firewall functionality, but that than connects through to a switch/patch panel. From there, cabling goes to 2 other switches supporting up to 40 network point and supporting 2 or 3 APs. In terms of a DHCP scopes, I wouldn't know how to check that but we did have the following statement from our 'technical consultant' who visits once a quarter. 'There are delays in the devices receiving IP addresses from the Draytek router and sometimes they don't receive an IP address at all.

 

Since then, one of our switches died (wouldn't power up) and a colleague was walked through pulling/inserting cables on the 2nd switch/ patch - this was a 'technically blind' process, the colleague has no idea about what he was doing, just asking as a bizarre 'remote' service! I have made my dissatisfaction about that and that they should have come on site - they're only 30 minutes away. Now, as it happened I was in the office this week along with several others, using the boardroom. This room has never had a good reputation for WiFi, and recently just our CEO and a major donor were in and they couldn't get connected to the internet and I believe it was the day the switch popped it's clogs. I and everyone else in the room got perfectly good Wifi, strong and stable. They fact this was after the switch died and re-cabling, I doubt it is a coincidence. It's not all good though, a 2nd half of the building is without any WiFi whatsoever.

 

So it sounds like the Draytek router is also your DHCP server, and as such, likely has a hard limit of how many devices it can support at any given time that you may be reaching.

 

It could also be that the second switch that died ran the WiFi for the other half of the building, and had vLans setup on the ports for the APs. When your colleague moved the cables to the 1st switch, the ports he connected to them most likely don't have the vLans setup, which is why the WiFi is no longer working. This is assuming that vLans are setup of course. I'm also assuming that both switches are PoE.

[Ditto]

The router we have is a Draytek Vigor 2862n - tech specs are at https://www.draytek.co.uk/products/business/vigor-2862#specifications.

[simpsonj]

The router we have is a Draytek Vigor 2862n - tech specs are at https://www.draytek.co.uk/products/business/vigor-2862#specifications.

 

It does look like it can cope with 1022 devices, potentially up to 3066 (Larger Subnets - up to 1022 IPs per subnet (LAN1-3) - New!) so as long as it's configured correctly, that shouldn't be a problem.

[Ditto]

Well, having reached out to our old IT provider who for no sensible reason remain involved, have stated the following in relation to a request for patch status and system logs.

 

System logging - disabled unless there is a fault to be monitored - fair enough, up to a point

Due to risk of firmware updates bricking the router, only done if there is a direct security risk or defect with the router - Hmmm, not so sure on that one.

[Ditto]

Possibly this is going slightly off thread, but as the OP, I guess that's allowed.

 

To my pleasant surprise, I have managed to get some data usage figures for the last 10 months. Normal usage would be 9-5, Mon-Fri. In GBs, download has varied between 200 to 350, and upload from 75 to 110. Now, I can accept that this alone probably isn't the sole parameter to use to determine the ISP option, but assuming a VDSL solution, what would seem appropriate. I feel a leased line is OTT, a single SOGEA line under spec, but dual SOGEA would be about right - but I'd like to be a little more scientific. Early in the thread, I believe we established we are getting close the the max possible on our VDSL line so would expect similar with a second line.