Large school, Multiple Chromebooks & connectivity issues

23 views
Skip to first unread message

John Weir

unread,
May 24, 2022, 5:25:17 AMMay 24
to CESI-list
Hi all,

I am looking to connect with some schools who would be using a large number of chromebook devices. 10 weeks ago we changed over to a fibre connection and since then have had daily issues of broadband dropping when multiple chromebooks try to log in simultaneously. We have been fully engaged with PDST throughout this time and to their credit they are hard on the case. 

I won't bore you with the litany of troubleshooting but in short the finger of blame seems to be narrowing down to the fritz modem  ( 7530 model) being unable to handle multiple logins (60 - 70 simultaneously). One possibility is that there is a function or config issue on that modem that the old Fritz 7360 (which we used before the change to fibre) did not have.

Another area being considered is how the Chromebooks talk to each other. They seem to use P2P automatic updating. This in turn floods a network with multicast DNS requests. The more Chromebooks that come online, the more mDNS requests are sent and the more you suffer a problem. 

I was looking to connect with any other large schools (it probably would be in the secondary sector) with multiple chromebooks on a fibre connection to see if we are doing something different or have a different network setup.

many thanks,

John

Mark Delahunty

unread,
May 24, 2022, 6:07:17 AMMay 24
to cesi...@googlegroups.com
Hi John,
We had the same issue. It was due to our upload speed. We had to install a second line to handle the demand.
Regards,
Mark

--
--
You received this message because you are subscribed to the Google
Groups "CESI-list" group.
To post to this group, send email to cesi...@googlegroups.com
To unsubscribe from this group, send email to cesi-list+...@googlegroups.com
For more options, visit this group at http://groups.google.com/group/cesi-list?hl=en-GB where all messages are archived and are publically available to non members of the list. Messages may also show up in search engines etc.
Visit the web site www.cesi.ie
Attempts to use the list for commercial purposes may result removal from the list.
---
You received this message because you are subscribed to the Google Groups "CESI-list" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cesi-list+...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/cesi-list/bc21436c-91af-412e-abbb-8ee2e73886b9n%40googlegroups.com.
--

Cóilín Ó Coigligh

unread,
May 24, 2022, 6:39:11 AMMay 24
to cesi...@googlegroups.com
Hi John,
Have you a third party firewall in front of your fritzbox?
Our IT man is in today and this is what solved it for us. I have shown him your email if you want to give him a call.
Seán Carolan, Tantach, 083-4205405
Tantech are a Google partner.
Beir bua
Cóilín

--
--
You received this message because you are subscribed to the Google
Groups "CESI-list" group.
To post to this group, send email to cesi...@googlegroups.com
To unsubscribe from this group, send email to cesi-list+...@googlegroups.com
For more options, visit this group at http://groups.google.com/group/cesi-list?hl=en-GB where all messages are archived and are publically available to non members of the list. Messages may also show up in search engines etc.
Visit the web site www.cesi.ie
Attempts to use the list for commercial purposes may result removal from the list.
---
You received this message because you are subscribed to the Google Groups "CESI-list" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cesi-list+...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/cesi-list/bc21436c-91af-412e-abbb-8ee2e73886b9n%40googlegroups.com.


--
Cóilín Ó Coigligh
Bunscoil Mhuire
Baile Átha Troim
Co. na Mí
16646O

Mark Delahunty

unread,
May 24, 2022, 6:39:12 AMMay 24
to cesi...@googlegroups.com
Also John we had to get a larger number of ip addresses. As this was also causing connectivity issues. An easy way to identify this is to count up the number of devices connecting to the network at any given time including teacher phones, tablets etc and see if this is greater than the number of ip addresses you have on your network. 
Regards,
Mark

Áine Uí Choinne

unread,
May 24, 2022, 7:09:21 AMMay 24
to cesi...@googlegroups.com
John, we had the same problem here-we bought 30 chromebooks , in additional to what we had (PC, laptop, teachers phones, printers etc) and we couldnt have more than 19 or so connected at once. We installed a new router, €200 plus €200 for installation, a cheap enough fix, and now we have added 30 more chromebooks for the Junior side, and no connection problems at all. Hope that helps. 
Áine Uí Choinne , Gaelscoil Dhún Dealgan 

--

Val Gavin

unread,
May 24, 2022, 8:09:19 AMMay 24
to cesi...@googlegroups.com
Morning John
Just a question, are you using public IP addresses and if so how many have you been allocated, if public then you may have reached your allocated lot
Check with pdst.

You can email or call me offline anytime.

Val

Val Gavin Computer Services
0872671234 


--

Liam Onofrei - Ctrl Alt Del

unread,
May 24, 2022, 8:28:18 AMMay 24
to cesi...@googlegroups.com

Hi John,

 

Thanks for sharing.

 

I don’t think is the IP or asymmetrical speeds or CAT5 vs CAT6 related issues…

 

You have identified one of the bottlenecks: local broadcast, multicast traffic, mDNS or Bonjour.

Use the Wireshark and you will be shocked how much of your local traffic is non user generated noise but rather device to devices…

And is valid for both Google and Apple devices, designed to operate at home, in a smaller home network.

 

I will highly advise in to looking at network segmentation and / or VLANs.

The implementation of VLANs is not supported by PDST routers so you will need to apply some ”pen and paper” to create a segmented IT architecture.

 

Contact your IT Consultant and request a meeting to discuss the new approach in respect to network design.

 

Good luck and enjoy IT.

--

Reply all
Reply to author
Forward
0 new messages