Wireless planning for a conference, need advice for Netgear R7500

[Karl_Derbycon]

Hello there, each year I assist with the wireless setup for a conference in Louisville. We host 15 training classes prior to the conference, most of which require internet access. Training will consist of around 350 users. We have a few constraints, the WAN circuit is a symmetrical 100mbps connection, each training class has their own separate network, and the classrooms are close in proximity to each other.

In years past, we have been struggling to meet this demand due to poor equipment performance. Previously we used Asus RT-N16 routers running ddwrt. Years prior to last, were a mix of G routers rented from the hotel. As you can imagine, we have major issues with slow performance, disconnects etc. I would attribute this to the amount of access points in a single area (2 floors, most classes close to each other) and 3 channel choices on 2.4Ghz. Also, considering this is a hacker conference, we host a wireless training class that plays havoc with all the networks

This year we are isolating the wireless class to a more remote section of the hotel. We are replacing the Asus RT-N16 routers with Netgear R7500 X4 nighthawks. We will still need to keep the 2.4Ghz networks up for older clients, but will also have 5Ghz networks for each classroom. I've started doing research on channel overlap. What I don't understand is how I should cope with the way the R7500 handles the use of multiple channels and the lack of precise control over it.

Can you help clarify how the R7500 handles the use of multiple channels (if that's a thing) and how we can restrict it to use only a single 5Ghz channel so that it can be mapped out for separation between classrooms? any suggestions would be appreciated, thanks

 

[sfx2000]

Is it safe to assume that this is a Ballroom (for general and plenary type sessions) along with smaller 10-12 seat conference rooms for specific topics?

In my experience, for the smaller rooms - these can be supported by a single AP, so the real challenge is the ballroom scenario... Again, rough estimates, but consider 25 seats per AP, and might consider F4 reuse (1, 4, 8, and 11)...

Helps if you can get a floor plan and then you can map out the locations from there, esp for the ballroom.

I'm making the dangerous assumption that you do have a dedicated ingress router that can handle the 350/700 nodes on that large scale WLAN... (these days, if you have 350 attendees, figure that they have both a phone and a laptop, so double the number of estimated nodes just to be safe)

 

[Karl_Derbycon]

MSPaint skill showoff - stars are the proposed access point locations within the training rooms, which are defined below. We do not have access to all rooms during training. To give you perspective, floor 1 rooms belmont and aqueduct are directly beneath floor 2 rooms cherokee and iroquois.

Floor 1:
smaller rooms such as aqueduct, belmont, and pimlico C seat about 15 to 25 people. Pimlico A & B will be joined for about 50 people

Floor 2:

Smaller rooms seneca, iroquois, cherokee, and the prefunction room have about 10 people per class. Prefunction room will have the wireless hacking class. Keeneland, gulfstream hialeah, regency south (split for different classes A & B), conference theater, kentucky suite and churchill will have anywhere from 30 to 70 people each.

As for the hotel's equipment, in the past they had a nomadix device that did everything (internet gateway, dhcp, captive portal etc) and could handle traffic from hundreds of users without issue. This year it was replaced with cisco equipment, we are unsure of the capacity. They have access points in each room, but the price for labor of network segmentation far exceeds our budget. The hotel access points will be powered off during training.

 

[sfx2000]

hmm... Looks like the Louisville Hyatt-Regency, nice place

Everything looks ok except for Regency South, not sure if you guys are using that as a single ballroom style, or leaving the partitions in place, and just using it for large sessions... if it's sessions, there you might want a couple of more AP's.

Other than that - it's a nice venue, I've been there - talk to their network admin a week or so in advance to sort out VLAN's and Routing Info, along with who needs to do DHCP/DNS - some groups like to do their own, others prefer to let the conference center team.

Also - just as an FYI - might want to let the attendees know, don't try to hack the room/lobby wifi/network - there are other guests and probably other meetings concurrently running - one group I attended - they basically melted the entire hotel network, and remediation took a lot of time and cost a lot of goodwill to the group - and for the following year, we had to go somewhere else... (not this venue, but somewhere else in the Chicago area...)

 

[Karl_Derbycon]

Yep, that's the Hyatt, love that place and the staff is so friendly. We plan on using netgear R7500 routers for each of the classes. In years past, rengency south A & B has done ok with 50 people on each router. The theater usually has 70 people and requires an additional access point.

My issue is that we've ran into very slow connections and bleed over from nearby networks. By using 5Ghz, I hope to minimize this due to more channel choices. I'm just not sure how that works if the router uses 4 channels together to get AC speeds? I might be wrong about how that works


as for the hotel network, we've had minimal issues with it being messed with. The conference doesn't start till training is over and everyone in training paid a decent chunk of money to learn. Obviously a hand shake agreement means nothing, but we've been lucky so far.

 

[thiggins]

80 MHz bandwidth (4 channels) will be used only by clients that support 802.11ac.

If you don't want to allow that, you can just limit the link rate and/or channel bandwidth via the "Up to XMbps" wireless settings.

 

[System Error Message]

For wireless design of scale do not use consumer variants since it is not cost effective. For example you can get a 5Ghz only wifi AP for $80 from mikrotik that has A/N/AC and 5 Ghz is where you need to expand, not 2.4Ghz. The issue with any AP is when you mix protocols.

Have seperate AC and A/N APs, same for 2.4 Ghz. have legacy APs and newer APs. For example 1 AP could be using wireless AC on 5 Ghz and wireless N on 2.4 Ghz only while the other APs could use wireless A/N on 5 Ghz and b/g on 2.4 Ghz. The legacy ones can share the same channel on 2.4 ghz whereas 5 Ghz has loads of space. You might want to reuse your old APs for legacy.

 

[Karl_Derbycon]

If I kept 5GHz on a 20MHz channel, I wouldn't be able to achieve any speed records, however that would allow me to separate the channels enough so that they don't bleed over.

As for using a separate AP for 2.4GHz, I never thought about that. considering the amount of processing power in the R7500, I would imagine it could handle simultaneous networks without issue, however with so many clients it might be a struggle. Good suggestion, we made consider putting additional an AP in the rear of the room.

 

[System Error Message]

What i mean is on 2.4 Ghz you should use 20 mhz channels from 1 to 13. Channels 1,6,11,13 are non overlapping and even though some devices cant see channel 13 they can still connect to it. I noticed that in my neighbourhood full of 2.4Ghz wifi with really bad configs or auto none of them touch channel 13 or 12 so i get really good throughput on channel 13 (in my country channel 13 is legal)

On the 5 Ghz using 80Mhz channels there are still loads of available non overlapping channels. Limit the number of APs running legacy N and A while the rest run wireless AC. When i said seperate i didnt mean 2.4 and 5Ghz, i meant the protocols (legacy and new). Not all APs need to run 2.4Ghz and 5 Ghz at the same time. 5Ghz has less range but more channels than 2.4 so some APs just run 5Ghz while some should run both 2.4 and 5Ghz.