Low RSSI of an AP | AP's transmit power | A proper RSSI of an AP is the prerequisite for good experience. Check the AP's transmit power. | Run the display radio { all | ap-id ap-id } command on the AC and check the CE/ME field in the command output. | When multiple APs are deployed for providing continuous coverage, set the transmit power for APs based on the interval between APs. Ensure that the RSSI is over –65 dBm for STAs at the coverage edge. Reference RSSI when the interval between APs is 14 m: · 7 dBm@2.4G · 10 dBm@5G | Adjust the AP power and positions. |
Low RSSIs of STAs | Proportion of STAs with low RSSIs to STAs with high RSSIs connected to an AP | A proper RSSI of a STA is the prerequisite for good experience. | Run the display station ap-id ap-id command on the AC. | The RSSI of a STA is higher than –65 dBm. The proportion of these STAs to the STAs with an RSSI of lower than –65 dBm should be higher than 1:1. | Adjust the AP positions to make STAs closer to the APs. |
Slow network access, frame freezing, and long ping delay (due to air interface reasons) | RSSIs of co-channel APs | RSSIs of co-channel APs indicate the interference of the co-channel APs to the local AP. | Run the display ap neighbor ap-id ap-id radio radio-id command on the AC to check the RSSIs of APs on the same channel. | RSSIs of co-channel APs should be as low as possible. An RSSI higher than –92 dBm affects performance of the local AP. | Adjust the AP power, channels, and positions. |
Channel utilization | The channel utilization shows whether the current channel of STAs is busy. | Run the display radio { all | ap-id ap-id } command on the AC and check the CU field in the command output. | A low channel utilization indicates good performance. When the channel utilization is higher than 50%, performance is acceptable. When the channel utilization is higher than 70%, experience is poor. | Perform air interface calibration to optimize radio parameters. |
Radio noise floor | The noise floor indicates the interference. | Run the display ap traffic statistics wireless ap-id ap-id radio radio-id command on the AC to check the Wireless noise(dBm) fields in the command output. | The noise floor should be as low as possible. A noise floor of higher than –100 dBm affects performance. | Perform air interface calibration to optimize radio parameters and check surrounding interference. |
Ratio of low-rate air interface packets on an AP | Low-rate data packets occupy the air interface for a long time, decreasing the overall air interface efficiency. | 1. Run the reset wifi radio-statistics-sdk radio radio-id command in the diagnostic view of the AP. 2. Run the display wifi radio-statistics-sdk radio radio-id command every 5s to check the MCS counts (0..9): a, b, c, d, e, f, g, h, j, k field in the command output to check packets sent at different rates in ascending order. | · Smaller value at the front and larger values at the rear are recommended. · (a + b + c + d + e):(f + g + h + j + k) < 1:1 | Adjust the AP power and positions and perform air interface calibration to optimize radio parameters. |
Proportion of power-saving STAs | If STAs connected to an AP enter the power-saving state, the AP needs to cache packets for the STAs, affecting AP performance. | 1. Run the display station statistics ap-id ap-id command on the AC to check the Stations work in power save mode field in the command output. 2. Run the display station ap-id ap-id command on the AC to check the total number of STAs. | The number of STAs in power-saving mode should be as small as possible, and the proportion of such STAs should be lower than 50% of all STAs. | Run the active-dull-client enable command in the SSID profile of the AC to view to enable the function of preventing STAs from entering the power-saving mode. NOTE: After this function is enabled, STAs occupy additional bandwidth. If the fault is rectified and the generated overhead is generated, enable this function. |
A large number of packets buffered in the software queue of an AP for a long period of time | If a large number of packets are buffered in the software queue of an AP for a long period of time, it indicates that these packets are not forwarded on the air interface in time. As a result, the AP performance is degraded. | Run the display wifi txq-buf radio radio-id command in the diagnostic view of the AP to check whether the values of the buf_used field of each txq and SW queue stats field of each TID are high for a long period of time. | The number of packets buffered in the software queue of an AP should be as low as possible and not larger than 600 for a long period of time. | Perform air interface calibration to optimize radio parameters. |
Proportion of broadcast and multicast packets to unicast packets on an AP | Multicast and broadcast packets are transmitted at low rates, and occupy air interface resources for a long time. The proportion of broadcast and multicast packets to unicast packets needs to be properly controlled. | Run the display ap traffic statistics wireless ap-id ap-id radio radio-id command every 5 seconds on the AC to check the values of the Wireless unicast frames(TX) and Wireless broadcast frames(TX) fields. Calculate the proportion between them. | The number of broadcast and multicast packets should be as small as possible, and the proportion of broadcast and multicast packets to unicast packets should be lower than 1/3. | Configure a rate limit for broadcast and multicast packets. |
Number of STAs connected to an AP, and proportion of STAs associated with the 2.4 GHz radio to that associated with the 5 GHz radio | 2.4 GHz channels have severe interference, while 5 GHz channels have relatively lower interference. Therefore, configure an AP to allow STAs to preferentially connect to the 5 GHz radio. | Run the display station statistics ap-id ap-id command on the AC to check the values of the Stations associated with 2.4G band and Stations associated with 5G band fields. | The number of STAs associated with the 5 GHz radio should be as large as possible and be larger than that associated with the 2.4 GHz radio. | - |
Slow network access, frame freezing, and long ping delay (due to wired network reasons) | Large traffic on an AP | The AP with large traffic may be occupied exclusively by a single STA. | On the web platform, choose Monitoring > AP. In AP List, check the statistics on Wired-side Throughput. | If the wired-side throughput of the AP is higher than 50 Mbit/s, check whether large-traffic STAs are connected to the AP. | - |
Proportion of large-traffic STAs on an AP | If a STA connected to the AP occupies high traffic bandwidth, experience of other STAs connected to the AP is degraded. | On the web platform, choose Monitoring > User > User Statistics. In User List, check statistics on Throughput. NOTE: Statistics on the STAs connected to a specified AP can be displayed by AP name or AP ID. | The throughput of a single STA should not exceed 15 Mbit/s. | Run the following commands in the traffic profile to set the upper and lower rate limits for a single STA: rate-limit client up 10240 rate-limit client down 10240 |
Negotiation rate on wired interfaces of an AP | The rate of an AP's wired interface should be negotiated to be the same as the rate of the connected interface to prevent the wired interface from becoming a bottleneck. | Run the display interface GigabitEthernet 0/0/1 command on the AP to view interface information. Speed : 1000, Loopback: NONE
Duplex: FULL, Negotiation: ENABLE | If the AP connects to a gigabit interface, the local interface on the AP must also be a gigabit interface. | Check the rate of the peer interface. Check whether the Ethernet cable is faulty. If so, remove and install the Ethernet cable. |
Proportion of broadcast and multicast packets to unicast packets on the wired network of an AP | If there are too many broadcast and multicast packets among wired packets on an AP's uplink interface, the AP performance is degraded. | Run the display interface GigabitEthernet 0/0/1 command every five seconds on the AP (assuming GE0/0/1 is an uplink interface) to check the numbers of multicast and broadcast packets in the input and output directions. Calculate the proportion of the multicast and broadcast packets to unicast packets in both directions. | The proportion of multicast and broadcast packets on the wired network of an AP should be as low as possible, and the proportion of unicast packets to multicast and broadcast packets should be lower than 1/3. | Set rate limits for multicast and broadcast packets. |
CAR threshold on an AP | If the CAR threshold is too low, some packets will be discarded. | Run the display cpu-defend statistics { wired | wireless } command on the AP to check the numbers of forwarded and discarded packets. | Check whether a specified type of service packets are discarded due a low CAR threshold. If so, service performance is affected. | Evaluate influence of the CAR threshold setting and modify it. |
CAR threshold on an AC | If the CAR threshold is too low, some packets will be discarded. | Run the display cpu-defend statistics { wired | wireless } command on the AC to check the numbers of forwarded and discarded packets. | Check whether service packets of a specified type are discarded due to a low CAR threshold. If so, service performance is affected. | Evaluate influence of the CAR threshold setting and modify it. |
Slow network access, frame freezing, and long ping delay (due to low device capabilities) | CPU and memory usage of an AP, and top 3 processes occupying the most CPU and memory resources | High CPU or memory usage of an AP reduces the AP performance. | Run the following commands multiple times in the diagnostic view of the AP to check the CPU and memory usage. 1. Run the display cpu-usage command to check the CPU usage according to the CPU Usage field. In the command output, the CPU usage of each process represented by PID is displayed. 2. Run the display memory-usage command to check the memory usage according to the Memory Using Percentage Is field. | The CPU or memory usage of an AP should be as low as possible. The CPU usage should not exceed 80%, and the memory usage should not exceed 90%. | - |
CPU and memory usage of an AC, and top 3 processes occupying the most CPU and memory resources | If the CPU or memory usage of an AC is too high, the AC performance is degraded when service traffic passes through it. | Run the following commands multiple times in the diagnostic view of the AC to check the CPU and memory usage. 1. Run the display cpu-usage command to check the CPU usage according to the CPU Usage field. In the command output, the CPU usage of each process represented by PID is displayed. 2. Run the display memory-usage command to check the memory usage according to the Memory Using Percentage Is field. | The CPU or memory usage of an AC should be as low as possible. The CPU usage should not exceed 80%, and the memory usage should not exceed 90%. | - |
