"Technical stickers" How should the WiFi network be set up at a large conference site?

Wi-Fi network deployment is far more complex than most people think, not to put on dozens of AP bandwidth automatically increase dozens of times times, on the contrary, simply put dozens of AP bandwidth due to the competition between APS quickly make the bandwidth down to almost unusable. In fact, this question can be written in a book, only exhaustive here, briefly speaking about a. For large-scale activities to do WiFi planning, follow these steps to do:
Situation Survey: first from the organizer to obtain the site size and number, distribution, including site map. There is an approximate estimate of the size and deployment of the network. In general, for everyone to plan for at least 1 client devices, the past experience can be planned according to 0.5 clients, due to the popularity of smartphones and tablets, the future is estimated to 1.5~2 a client closer. Mobile phones and laptops or tablets may be on the Internet at the same time.

Bandwidth Estimation: The conference is to ensure that participants can use relatively lightweight Internet applications, the most basic of each device to allocate 500kbps of available bandwidth. On this basis to consider the characteristics of large-scale activities. If it is a press conference, then there will be a lot of people uploading the video, bandwidth allocation needs to reconsider, everyone at least one device should be guaranteed 1Mbps bandwidth. If it is a panel discussion, then the bandwidth requirement will be much smaller. Is the bandwidth typically required by some typical applications.

According to the above two points can calculate the bandwidth requirements for each region, the next step is AP planning . Although 11g is known as 54Mbps bandwidth, the actual maximum available is 25Mbps, which means that up to 50 devices can be viewed at the same time (in this case, the user experience has been very bad because the client is competing with each other, usually in a fold). 11n for most phones can only guarantee 35Mbps, for laptops and other support MIMO can be guaranteed to 70Mbps or even higher. Follow this principle to map out the area that each AP should cover accordingly. In order to ensure the quality of communication, in order to ensure a better experience, in fact, should control each AP access to the device does not exceed the number of just half of the calculation.

The next step is to allocate the channel . Since the domestic can only use the 2.4GHz frequency band, this frequency band, although claimed to have 11 channels (some countries have 13), in fact, only 1,6,11 three channels that do not overlap each other can be used. Cover each of the three channels as if they were not overlapping (see). Sometimes, if you cannot overwrite without overlap, consider using a sector antenna to divide the coverage area into several sectors.

Once the channel allocation is complete, the wireless network will be deployed on the ground (in fact, before the above theoretical work should be done on-site exploration, considering the effects of walls and various reflectors, here in order to simplify the omission). The deployment should consider using a high-gain antenna, but reduce the transmit power of each AP, so that its coverage area is basically in line with the planning area. Note that the power is not the bigger the better, should let each AP only cover the planned area, do not someone else. Deployment may require a number of on-site measurement tools to evaluate the effect of deployment to prevent dead ends due to multipath interference. Is the difference in the entire area after deploying with 11g and 11n network deployment. The red area indicates that the coverage is not ideal, and you can see that the 11n network is very good for multipath interference suppression. In a few years try not to think about compatibility issues, the deployment of the 11g mode should not be turned on. It still looks like it needs to be compensated for by the 11g access Point's own power and antenna adjustments, or even by adding additional access points.

· Wired Network Planning deployment : Each 11g ap should be connected to at least a gigabit upstream port, and 11n APs should be connected to the gigabit upstream port. The final export also must ensure enough bandwidth, uplink transmission site data, down for everyone bored or need to check the relevant information, but also according to the second step above the total results calculated according to a certain proportion of the reservation (depending on the nature of the activity). If the domestic also need to consider the export of multiple operators.

· SSID Assignment : In fact, there are few cases where the user has already allocated a seat, and most of the cases have no way of pinning the user on an AP, so it is more common to have all APs set up the same SSID. Here actually involves the management of the thin AP and AP Controller, because the various programs are different, it is not counted.

· user authentication and bandwidth control : In order to prevent malicious network, it is best to do Basic authentication to users, such as the ticket to collect the account name and password. At the same time, for each account to limit bandwidth usage, this will also involve user authentication and bandwidth management, usually need additional server to handle.

· reject weak signal Client Access : Thank you @ Wei Bing and @ Cao Mengdi, by interacting with them I feel that this is also very important, so I would like to add it separately. The client signal strength measured by the AP assigns the appropriate AP to the client, and if an AP can receive a client signal but is too weak to support a certain threshold rate, the client is denied access from the AP to prevent the pig's teammates from having too much bandwidth (he passes 1bit time you can pass 54bit! ) to lower the performance of the entire AP with the lowest rate.

At this point a simpler WiFi network was deployed. You can't find the link to the original text, I can only according to the news that there are 3000 people present, guess the organizers underestimated the participants ' bandwidth requirements, because

· Insufficient number of APS (should be around 100, at least 50)

· AP planning unreasonable (too many packet collisions)

• Or AP crashes (too many access users per AP)

• Or the AP controller crashes (unable to respond to so many AP Access/Disconnect requests at the same time)

• Or the authentication server crashes (unable to authenticate so many users at the same time)

• Or the egress bandwidth is too narrow (at least 300MB upstream, 300MB downstream, as my estimate requires)

• Management clutter (no control per client device traffic).

The Super Bowl organizers need to deal with 73,208 users, have more than 700 access points, and can support 30,000 connections at the same time (a little bit less, so enthusiastic game, users should spend more time on the phone than the press conference).

American classrooms are also scary, and the Apple notebooks that clean up the water don't include the tablets and phones in their bags!

"Technical stickers" How should the WiFi network be set up at a large conference site?