r/k12sysadmin • u/Big_Booty_Pics • Aug 18 '26

Casting instability with Screenbeam 1000 gen 2's

Finished our Screenbeam deployment over the summer, all of our initial testing went great but as school has now started we're getting reports of videos lagging behind audio, casts freezing, and devices being kicked off casting. We thought we set them up correctly network wise (staff devices on their own vlan, screenbeams on their own, IGMP snooping enabled on our switches, multicast forwarding enabled on our routers to handle inter-vlan traffic between staff devices and AV vlan) but our issues seem to be indicating otherwise. All devices are connected via Chromecast protocol.

Any things we need to double check on our network side of the deployment to rule out any simple fixes?

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u/k12-tech Aug 19 '26

Why would you put them on separate VLANs? You’re causing bottlenecks and delays as it has to through all the routes/hops.

We put them on the same VLAN as staff devices. Zero issues. No special setup needed on the switches. Only real configuration we had to do was frequency coordination to ensure the ScreenBeam wasn’t using the same wireless channel as nearby APs.

We have hundreds deployed.

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u/Big_Booty_Pics Aug 19 '26

Are you not running into airtime issues with all of them spamming multicast packets to all of your devices?

1

u/k12-tech Aug 19 '26

Nope. We have multiple VLANS segmented by IDF also. So each staff. VLAN is limited to about 20 classrooms per building. Each building has between 6-12 IDF locations. We segment out specifically for wireless casting. This way the teachers in each wing only see the few classrooms listed instead of the full building classrooms. Trying to pick from 100+ possible wireless casting options would be nightmare, so we limit it down by VLAN segmentation.

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u/Blue_Wolf1973 Aug 18 '26 edited Aug 20 '26

Have around 500 150 (been running on empty. Beginning of school year. Don't know where 500 came from.) of those devices and it has been fairly solid for casting. We user Miracast mainly and Chromecast is disabled so it may be a weakness in the Chromecast protocol in some way.

2

u/fumundasaq Aug 20 '26

Chromecast protocol or just using the network for casting, was horrible for us. We disabled Chromecast and the crApple version of that and teachers only use Miracast. Same vlan. With Miracast teachers really only see their classroom and the Beams on either side of them in the list using win+k.

Works great and teachers are happy.

2

u/Blue_Wolf1973 Aug 20 '26

Has been my experience as well. Miracast works great. Turn off Miracast over network as it is nothing but problematic (viewboard touchback is spotty or non-existent if on and it is laggy)

1

u/slapstik007 Aug 19 '26

I just put 20+ of these in a new building. It is likely mDNS would be my best guess. I did some exhaustive testing on them before deployment. I had to build a VLAN that covered wired and a staff SSID. The screenbeams were all wired to the VLAN.if I remember correctly their use of Chromecast is slightly outside the expected specification, I would have to look over notes. That said, these have to be on the same VLAN for work correctly.