Training, Certification & Career

I just have a question about broadcast domain sizing for the user VLANs. Currenlty we are using class C's for the User VLANs with pooling, which works fairly well. But, what is the largest recommended user network   /23, /22 or /21?

 

Thanks.

 

Hope in the correct location.

 

Dan

 

You can make it as large as you want, as long as you enable "drop broadcast and multicast" on your Virtual AP.

I have been reading in the forums, checking that box will deny printing.

Also, wont it prevent clients from getting DHCP?

What kind of printing?  If you use ip printing, you should not have a problem.  If you use Airprint, you would only need to have airgroup on to discover printers.  It will not prevent clients from getting DHCP, no.

 

We are moving from IP printing to named printing soon.

That is good to know about the DHCP.

Is it best practice then to Deny Broadcast and Multicast on all VAPs?

 

Currently we do not allow printing from certain SSIDs.

What is named printing and what protocols does it use? Drop broadcast and multicast is a standard way to improve performance.

Printing over DNS.

---

frandydan@fhda.edu wrote:

Printing over DNS.

---

 

 

Printing over DNS is normally unicast, so you should be fine.

Is there a particular VLAN size/connected device number that you recommend enabling drop multicast/broadcast on?

---

@hipzilla wrote:
Is there a particular VLAN size/connected device number that you recommend enabling drop multicast/broadcast on?

---

 

 

All of them, unless you are running an application that relies on broadcasts. Dhcp and ARP are always passed through...

*Any* size?

does that mean we can move away from Vlan Pools?

bosborne,

 

Yes you can.  You just need to enable Broadcast Suppression (Drop Broadcast and Unknown Multicast) on that Virtual AP.

 

Is there a definitive answer/quide for this?

We want to move away from pooling and are looking at /20 or maybe even /19 networks.

Our support partner has recommended no bigger than /21 or at a push /20, but Im sure Id seen /16 mentioned in a design guide.

Cheers
Original Message:
Sent: Nov 14, 2014 07:10 PM
From: Colin Joseph
Subject: User VLAN IP size ? what is the largest recommended VLAN size for a Wireless user VLAN?

bosborne,

 

Yes you can.  You just need to enable Broadcast Suppression (Drop Broadcast and Unknown Multicast) on that Virtual AP.

 

Check the Single VLAN Architecture VRD.

"Controller and tunneled APs make it possible to scale to larger subnets in the range of /22 to /16."

Also check the considerations on other components in your network, like your L3 switch.

------------------------------
Herman Robers
------------------------
If you have urgent issues, always contact your Aruba partner, distributor, or Aruba TAC Support. Check https://www.arubanetworks.com/support-services/contact-support/ for how to contact Aruba TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.

In case your problem is solved, please invest the time to post a follow-up with the information on how you solved it. Others can benefit from that.
------------------------------

Original Message:
Sent: Sep 06, 2021 05:03 AM
From: Darren Rigby
Subject: User VLAN IP size ? what is the largest recommended VLAN size for a Wireless user VLAN?

Is there a definitive answer/quide for this?

We want to move away from pooling and are looking at /20 or maybe even /19 networks.

Our support partner has recommended no bigger than /21 or at a push /20, but Im sure Id seen /16 mentioned in a design guide.

Cheers
Original Message:
Sent: Nov 14, 2014 07:10 PM
From: Colin Joseph
Subject: User VLAN IP size ? what is the largest recommended VLAN size for a Wireless user VLAN?

bosborne,

 

Yes you can.  You just need to enable Broadcast Suppression (Drop Broadcast and Unknown Multicast) on that Virtual AP.