Monitoring RF 802.11 Packet Errors
Damaged packets cannot be read by devices, therefore they are discarded and re-sent if they are data packets. (See Monitoring the Percentage of RF Packet Retransmissions.) This increases the number of re-sent packets and decreases the throughput on the network. (See Monitoring RF Throughput.) Voice and video packets are dropped but not re-sent, decreasing the quality of VoIP and streamed media. Packet errors can occur when:
Noise causes spurious packets.
Signal degradation occurs causing a weak signal.
Channels are too congested, causing packet collision and corruption.
Hardware or drivers are faulty.
Excessive packets are being received from one source—this could be a flood attack.
In Network Director, at the configured interval (set in Setting Up User and System Preferences), the total number of 802.11 packet errors is compiled and plotted on a line chart monitor. You can monitor packet errors for the following:
An access point
An entire site
A floor of a building
A wiring closet
Unlike access points and radios, which appear on the list automatically, sites, buildings, floors and wiring closets must be configured by you.
To view RF packet errors over a fixed period of time:
- Select Monitor Mode in the Network Director banner.
- Select any view from the View pane.
- Expand the list in the View pane, then select one of the
objects listed in Table 1:
Table 1: Objects in the View Pane
Individual access point
Wiring closet—to create a wiring closet, see Setting Up Closets.
Selecting a floor in logical view displays all access points on that floor—to create a floor, see Configuring Floors.
Selecting a building in logical view displays all access points in that building—to create a building, see Configuring Buildings.
Selecting a site from the logical view displays all access points in that building—to create a site, see Creating a Site.
The Monitor mode RF tab becomes available when you select one of the objects listed in Table 1 .
- Click the Monitor mode RF tab to view the four
basic monitors, which includes the RF packet error monitor.
The populated RF Packet Errors monitor opens, displaying the number of packet errors that the selected object has experienced over the past hour.
- Optionally, change the timeframe covered by the monitor by selecting a different time from the list.
- Click Help (?) for help interpreting the throughput chart or see 802.11 Packet Errors Monitor.