Forum

Realistically how many Cisco lwapps can be in the same broadcast domain? Are they chatty?

Thanks

I assume you mean Light Weight Access Points. LWAPP is a Cisco protocol, not a device.

We really have two possible broadcast domains here. One wired, the other wireless.

Wirelessly, they should be broadcasting about the same amount as without it. As far as the wired connection goes, I honestly don't know. I wouldn't think it would have to be excessive - ie any more than it needs to be.

When I worked on the wired side, CDP (Cisco Discovery Protocol) could be very chatty, and was unfortunately often diasabled because of that.

Here is a section from a Cisco best practice guide:

? Limit the number of access points per VLAN. A good number is around 60 to 100 if you use a later code version. This helps to minimize reassociation problems in case of network failure. Cisco IOS based APs can be deployed on higher densities subnetworks. Always make sure that the underlying layer 2 and layer 3 topology is properly configured (spanning tree, loadbalancing, etc).

Chad,

Thanks for clarifying that - I'm glad someone had a more thorough answer than mine.

I should have said Cisco capwap APs really, I guess would have been the best term. I've heard the 100 number before but wasn't sure how true that number is. Seems pretty low.

Kevin,

The access points are pretty chatty on the initial boot and discovery phase. I've done deployments where all of the APs where dumped into a single VLAN with around 100 APs. I didn't see any issues. Back in the 4.2 days there were issues with having that many APs in the same VLAN as the Management IP due to the amount of broadcast traffic the APs create during the discovery process. How many APs are you looking to deploy?

500ish or maybe two vlans with 250 per vlan.

I am working on a new topology using 6500's, WiSM2s, and VSS. The old way is a PITA that uses layer3 to the edge (L3 access layer). With VSS I can get rid of spanning tree and use both redundant uplinks with etherchannel. No more routing to the edge to get rid of spanning tree. I'd really like to just have one vlan for the APs.

So when you route to the APs the controller doesn't hear all the L3 broadcast since it isn't in the same subnet. I was hoping get rid of option 43 and DNS. Just let the APs find the controller with the L3 broadcast since they could live on the same subnet/vlan. I guess I'll have to rethink my plan of attack. Is there away to turn off the L3 broadcast?

Even with them all broadcasting the slowest link is a gig. Though everything has to look at every packet for a quick burst I still have doubt it is going to max anything out. I just wonder if that 100 AP statement was for older chattier code and APs that only had 100 meg interfaces.

thanks

I haven't done a deployment that large for a single site so I can't really comment. The L3 broadcast is one of the discovery mechanisms so I doubt there is a way to disable it. I would run your design by your local SE and see what they have to say about it.

LOL. That is the third time I have heard that today. Our SE is alright but he isn't a WiFi guy. I sent him an email about it though.

Your SE should have access to the right person to ask.