Wireless Network Architecture and Design

Various forms of security are well suited for implementation at AP.

The client must negotiate membership and security measures in the following order:

1. Use the SSID that matches AP

2. Certify to AP

3. Use a packet encryption method to ensure the confidentiality of the data (optional)

4. Use a group authentication method to ensure the integrity of the data (optional)

5. Establish a connection with AP

The SSID string is used to match the client to the appropriate WLAN (and VLAN in the wired network).

SSID is not a security measure, but is only used to divide WLAN into logical user groups.

The two things that IEEE 802.11 clients and AP must identify are authentication and encryption.

The client must authenticate to AP using one of the following methods:

1. Open authentication

2. Shared key (PSK)

The authentication process will end at AP.

The IEEE 802.1x protocol can be used for port-based authentication.

Roaming refers to the process of switching an association from one AP to another AP association so that the wireless connection can be maintained while the client is mobile.

For clients to roam, adjacent AP must first be configured to use different channels that do not overlap.

The roaming process is entirely driven by wireless client devices rather than AP.

When the transmitter scans other channels, packets arriving through the original channel will be lost, so they cannot be received.

The goal of layer 2 roaming is to ensure that the offline time is as short as possible so that latency-sensitive applications are not adversely affected.

Regular AP itself does not support layer 3 roaming and requires the use of other tools that can be deployed in the IEEE 802.11 network.

When designing a WLAN, the two basic goals are as follows:

1. Determine the size of the AP cell

2. Select the channel used by each AP

When using IEEE 802.11b, the throughput of a single AP can usually be as high as 6.8Mbps, while IEEE 802.11g and IEEE 802.11a can be as high as 32Mbps.

Generally speaking, the size of the AP cell depends on the transmission power of the AP. The higher the power, the greater the coverage.

If an AP fails, the area it originally covered will become a static zone.

When deploying AP, cells can be arranged regularly and different channels can be used alternately.

If you are using Cisco AP in your network, you must know whether each wireless device is compatible with the features you intend to use. Cisco's CCX can meet this requirement by determining whether the device is CCX compliant.

When planning for wireless deployment, try to satisfy that the wireless signal in the coverage area should not be less than-70dBm.

In general, the maximum number of access users for each AP is about 40. In order to ensure the use of users, it is recommended to estimate 30 users per AP access and 80 users for Gaomi AP.

When the number of 2.4G AP in the same space exceeds 3, or the number of 5G AP exceeds 5, co-channel interference will occur.