Contents

About radio and roaming optimization· 1

Optimization principles· 1

Optimization recommendations· 1

Radio optimization· 1

Client access optimization· 6

Client roaming optimization· 8

About radio and roaming optimization

In the rapid development era of information technologies, the demand for massive connections between people and things, and things and things in scenarios such as mobile office, smart education, smart healthcare, and mobile payment brings unprecedented challenges to wireless network capacities. Wi-Fi6 technologies that feature low power consumption, high bandwidth, and low latency have become the first choice of increasing enterprises for campus network access.

Besides continuous product innovation, H3C also focuses on experience optimization and developed the iRadio, iStation, iEdge, and iHeal technologies to optimize WLANs from radio performance, roaming access, application guarantee, and network automation.

Optimization principles

Considering limited band resources, ubiquitous interferences, and various scenarios, clients, as well as network services, H3C optimizes WLANs from the following aspects:

·     AP selection and deployment

¡     Select AP types (for example, high-density AP, panel AP, and outdoor AP) based on the scenario.

¡     Adjust AP spacing according to user density.

¡     Leave a proper distance between an AP and an interfering device (a minimum of 3 m or 9.84 ft as a best practice).

¡     Make sure the minimum signal strength and signal-to-noise ratio are as follows:

-     Minimum signal strength: ≥ –65 dBm indoor or ≥ –70 dBm outdoor.

-     SNR: ≥ 25 dB indoor or ≥ 20 dB outdoor.

¡     Use DFS with caution. In low-density deployment, disable DFS as a best practice. In high-density deployment or 40M bandwidth, configure DFS as needed.

·     Radio performance

¡     Use iRadio to adjust AP channel, bandwidth, and transmit power.

¡     Configure broadcast and multicast suppression.

¡     Configure fair scheduling for clients to share radio resources equally when the network is not busy.

·     Client access

Use iStation to ensure that each client can access the optimal AP.

·     Client roaming

Use iStation together with 802.11k, 802.11v, and 802.11r to guide clients to fast access the optimal AP.

Optimization recommendations

Radio optimization

Radio optimization is performed from the following aspects:

·     Select the optimal channel and bandwidth, and set a proper transmit power.

·     Adjust the transmit rate to balance coverage and roaming performance.

·     Control multicast and broadcast to reduce radio resources used by unnecessary packets.

·     Use load balancing and fair scheduling to improve efficiency.

Wireless transmission is vulnerable to environment changes and problems such as multipath can cause complicated signal attenuation in various directions. Therefore, the implementation of WLAN often requires a series of activities, such as thorough network planning, detailed onsite engineering surveys, and continuous optimization after deployment. Continuous optimization can be time-consuming and expensive if performed manually.

RRM is developed to provide dynamic radio adjustment. It automatically collects and analyzes wireless environment statistics, and then adjusts the following radio parameters as needed to maintain the best Internet experience:

·     Channel

A radio can operate in limited channels and interference might increase as the environment changes. RRM can automatically adjust the working channel of a radio to reduce interference.

Figure 1 Channel adjustment

·     Power

Using fixed transmit power cannot provided balanced coverage and interference performance, and can also cause client sticky or weak-signal access.

RRM can adjust the transmit power of each radio to balance coverage and roaming while minimizing inter-device interferences. You can also deploy APs at proper spacing and specify proper transmit power for the APs to ensure coverage and throughput and reduce inter-device interference.

Figure 2 Power adjustment

·     Bandwidth

Large bandwidth increases the negotiated speed of APs and clients, but leads to strong interference if adjacent APs using the same channel.

RRM can adjust the bandwidth of each radio based on AP density, AP model, and supported channels of each radio, ensuring that APs and clients can negotiate a proper speed.

Figure 3 Bandwidth adjustment

Use Table 1 through Table 6 to identify detailed radio optimization recommendations.

Table 1 iRadio optimization recommendations

Table 2 Transmit power optimization

Table 3 Broadcast and multicast optimization

Table 4 Load balancing

Table 5 Radio fair scheduling

Table 6 Anti-interference optimization

Client access optimization

802.11 standards and MIMO modes supported by clients differ greatly as wireless technologies develop rapidly. If clients supporting different 802.11 standards and MIMO modes exist in the same network, advanced features such as OFDMA and MU-MIMO of 802.11ax cannot take effect to the full extent because some clients do not support these features. This affects the network transmission performance.

To resolve the issue, H3C adopts the following methods:

·     Access optimization

Client access involves three stages: scanning, probe, and association. Access optimization uses beacon/probe power limit, beacon auto hiding, probe auto rejection, and association control to guide clients to the optimal AP.

·     VIP user classification

This feature allows users to classify clients into level-1 VIP, level-2 VIP, and non-VIP clients and apply different policies to control clients from multiple dimensions, including access, forwarding, rate limit, resource reservation, and cloud report. This also meets the requirement of identity-based client control.

Use Table 7, Table 8, and Table 9 to identify detailed client access optimization recommendations.

Table 7 Access guide

Table 8 Experience guarantee

Table 9 Client access control

Client roaming optimization

WLAN protocols do not provide any mechanism for devices to guide or trigger client roaming and a client decides for itself when to roam and where to roam to. In actual application, how clients roam differ greatly.

Client roaming optimization classifies and labels clients by client capability, for example, support for 5G, 802.11k, and 802.11v, and allows devices to guide client roaming based on the labels.

Available optimization methods include:

·     Basic optimization

¡     Adjust AP coverage

¡     Adjust radio transmit power

·     Advanced optimization

See Table 10, Table 11, and Table 12.

Table 10 Roaming guide

Table 11 Roaming speedup

Table 12 Forced disassociation