District Wide ChromeCast (With 1:1 Chromebooks)

[Stephen Gale]

Thought I'd share how we are using and plan to use Chromecast in our district.

Note: We are a small district, but this is theoretically doable on larger scales.  Depending on your setup it may be more work than it's worth.

We are in process of upgrading our network from a 192.168.0.0 scheme to a 10.0.0.0 scheme and I figured while I was doing this, I would play around with vlans and subnetting. to create isolated Wireless Pockets for each classroom.  This is ideal for a 1:1 with Chromebooks (I will explain why below).  Here is what one one of our Buildings looks like (pardon the heat map, it was the easiest png I could find at the moment)

(As you can see, the recommended distribution of AC Wireless APs is not 1 for each room)

We presently have it where each classroom that has an Access Point also is setup with a hidden network named after the teacher.  When a student walks into range of the room, Chromebooks have the network pushed out to them from the admin console.

The passwords are set with random passwords generated from here and are varying in length, but never shorter than 50 random characters.  

From a networking scheme, I have set our Elementary School range in the 10.100.0.0/16 network, the Middle School in the 10.200.0.0/16 network, and the High School in the 10.300.0.0/16 network.  Each /16 network is then subnetted to /25 networks to keep things isolated at the classroom level.  This allows 126 hosts to be connected to a classroom and 32 non overlapping classroom networks per building (assuming I did my math right).

Now that each classroom has it's own personal network that students auto-join when they are in range (and logged into their Chromebook) we can have some real fun with Chromecasts

In order for a Chromecast to work on a network, 3 things must be present.  First is an internet connection.  Hopefully that is the case and should go without saying.  Second is MulticastDNS or mDNS.  This is also commonly called Bonjour traffic.  If your Wireless APs have Multicast filters, allow this one or if it requires a IP address to allow, it's 224.0.0.251/32.  The third thing that Chromecast's need is referred to PlugNPlay on the Google Chromecast documentation, but again, at the Multicast filter, allow 239.255.255.250/32.  I also noticed that IGMP Snooping must be OFF on all switches in order for Chromecast to work properly.

Next join a Chromecast to each classroom network, attach it to a Television or Projector (if you need a VGA converter, this one works great and they make male HDMI to Female VGA as well) and push out Google Cast to your students and teachers.

Now, when a Teacher or student comes into range of the Wireless AP, they are given Access to that teacher's Chromecast.  Any student (or teacher) in that classroom can present what is on their Chromebook for the entire class.

We have also set this up with a wired lab. Same idea. Keep 100% of the traffic on the Lab Vlan and add in the Wireless to that Vlan and voila, everyone in the Lab can share their screen on the Big Screen.

I'd love to hear your feedback and any other suggestions or questions about using ChromeCast, Google Admin Console, Chromebooks or the like.

[Bjorn Behrendt]

Chromecast only work on a 2.4 ghz wifi network and Chromebooks work best when connected to a 5ghz wifi network.   With the acceptation of the new guest mode, chromecast need to be on the same IP subnet as the device casting to it.

So I would suggest simplifying it a bit and have only 2 SSID's:  1st is "SSID_Chromecast" which is set to 2.4 only, and 2nd is "SSID_CB" which is set to 5ghz.    Having a different SSID per room is not a normal configuration, and I would suggest avoiding.

At my school we wanted a different set up, where the teachers have access to the Chromecast but not the students, so my network looks like.  I am guessing that if a teacher wants students to be able to cast I will try turning on Guest mode for just that Chromecast.

SSID1: "121" ~ Vlan2 (public), open, 5mhz only, hidden, mac address restricted (easy to pull with the chromebook inventory add-on)

SSID2: "Staff" ~ Vlan1 (main), WAP, 5mhz only, hidden.

SSID3: "Chromecast" ~ Vlan1, WAP, 2.4 only, hidden.

SSID4: "School Wifi" ~ Vlan1: WAP, dual-Channel, (used for all other devices)

SSID5: "School_Guest" ~ Vlan2 (public), open, AUP agreement page required to use, dual-channel, throttled.

Bjorn Behrendt M.Ed ~ Never Stop Learning

   b...@askbj.net | (802) 772-0003

   Google Apps For Education Certified Trainer & Administrator

My Sites

 ~ Edlisten.com ~ Educational Podcast

 ~ AskBj.net ~ Online Training and Ed Tech Resources

 ~ VTed.org ~ Vermont's Personal Learning Network

gClassFolders ~ Create Google folders for your class.

--
--
You received this message because you are subscribed to the Google
Groups "Google Apps K12 Technical Forum" group.
To post to this group, send email to k12ap...@googlegroups.com
To unsubscribe from this group, send email to
k12appstech...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/k12appstech?hl=en?hl=en

---
You received this message because you are subscribed to the Google Groups "Google Apps K12 Technical Forum" group.
To unsubscribe from this group and stop receiving emails from it, send an email to k12appstech...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Chris Franzen]

Awesome designs and thanks for sharing!

--

Chris Franzen

chrisf...@nokomis.k12.il.us  

Technology Coordinator | Nokomis School District

511 Oberle St. | Nokomis, IL  62075

QR
Please consider the environment before printing this email.

[Stephen Gale]

​

We originally had a setup similar to what you suggest,  Bjorn.  The problem was that the ChromeCasts were very similar to SMARTBoards in that only teachers could use them. We want to make Chromecasts student devices, but want to make sure that only the students in that classroom have access.  I am curious as to why you would suggest avoiding separate SSID's per classroom.  Just because it's not "normal" doesn't necessarily mean it's wrong, just different than what you're doing 

It's true that they only work on a 2.4 Ghz network, and for this reason we have our APs broadcasting on both ranges.  We have turned the power down on the APs so that they don't spill over into the hallways.  Hallways have their own APs that are setup as you have suggested, with general use SSIDs.

Our vlan scheme is presently :

vlan 100 "Elementary School for general student access

vlan 110 - 190 (by 10s) ES Classroom teachers

vlan 200 "Middle School" for general student access

vlan 210 - 290 (by 10s) MS Classroom teachers

vlan 300 "High School" for general student access

vlan 310 - 390 (By 10s) HS Classroom teachers

We also use a vlans 10-90 for district office stuff, management, administration, wired resources (printers, servers, etc.) and Guest network