Actually, they don't have to "respond." They have to process the incoming frame. If they aren't listening for that port, they will ignore or drop the packet.
If you are talking about client impact to CPU/battery/etc, I agree. If you are talking about airtime, the sum of the broadcast traffic is the same. Stopping broadcast over the air is the scalable way to solve Thanks Jake Snyder Sent from my iPhone > On Jul 26, 2016, at 6:00 AM, Osborne, Bruce W (Network Services) > <[email protected]> wrote: > > Actually, you reduce the broadcast traffic with smaller subnets. Remember > that all clients on the subnet *must* respond to a broadcast. > > Smaller subnets generally mean fewer clients responding to a given broadcast. > This leaves more airtime for productive Wi-Fi traffic. > > > > Bruce Osborne > Wireless Engineer > IT Network Services - Wireless > > (434) 592-4229 > > LIBERTY UNIVERSITY > Training Champions for Christ since 1971 > > From: Jake Snyder [mailto:[email protected]] > Sent: Monday, July 25, 2016 1:28 PM > Subject: Re: How big are your wireless segments? > > One thing to remember is that over the air you have the same amount of > broadcast whether it is one vlan or a pool of 4. > > For Example: If you have 4 client segments that are a /24, and each AP has a > client on one of the 4 subnets, you still send the sum of 4x /24 network > broadcast over the air. Meaning only on lightly loaded APs where you don't > have all 4 subuets do you get a net gain of airtime. Same applies for > link-local multicast. Smaller subnets in pools don't really gain you much > without the suppression techniques, and with the suppression techniques, you > don't need the smaller subnets. > > The place where pools/groups of vlans are attractive is where you may be > using public IPs and don't have a large contiguous block of IPs in which to > place clients. So picking 4 non-contiguous /24 networks is easier to do than > picking a full class B. > > > > On Mon, Jul 25, 2016 at 11:04 AM, Tim Tyler <[email protected]> wrote: > Brian, > We have pools of /22 /23/ and /24. We separate our pools from students vs > fac/staff (still on the same ssid). It may be ok to do /16. I know that > Aruba does a lot to prevent broadcast storms, but I feared the overhead of > one large segment might have on it. We also give students a different ip > pool depending whether they are in a residential building vs an > academic/admin building. This allows us to shape traffic differently. But > this will become less of an issue as we acquire more bandwidth (hopefully). > I am curious of those using /16, does that resolve your layer 2 issues? > Aruba does a good job of bridging many layer 2 solutions anyways, but having > one /16 vlan does seem enticing and perhaps unnecessary for bridging > protocols. However, I am curious about other overhead efficiency issues. > Tim > > From: The EDUCAUSE Wireless Issues Constituent Group Listserv > [mailto:[email protected]] On Behalf Of Brian Helman > Sent: Monday, July 25, 2016 10:22 AM > To: [email protected] > Subject: [WIRELESS-LAN] How big are your wireless segments? > > We are in the process of moving from a controllerless vendor to Aruba. Our > current design is very segmented, to keep wireless device broadcasts from > overwhelming the network and AP’s (we had this problem back in 11g days). > Presently, we’ve limited segments to /23’s (give or take). In your > controller-based environments, how large have you let these segments go? Is > a /21, /20 … viable? > > -Brian > > ____________________________________ > Brian Helman, M.Ed | Director, ITS/Networking Services | (: 978.542.7272 > Salem State University, 352 Lafayette St., Salem Massachusetts 01970 > GPS: 42.502129, -70.894779 > > ********** Participation and subscription information for this EDUCAUSE > Constituent Group discussion list can be found at > http://www.educause.edu/groups/. > ********** Participation and subscription information for this EDUCAUSE > Constituent Group discussion list can be found at > http://www.educause.edu/groups/. > > ********** Participation and subscription information for this EDUCAUSE > Constituent Group discussion list can be found at > http://www.educause.edu/groups/. > ********** Participation and subscription information for this EDUCAUSE > Constituent Group discussion list can be found at > http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
