Cisco Cisco Aironet 350 Wireless Bridge 技術マニュアル
ping the server or the device you target:
Check the network card, hub or switch, and cabling at the far side.
a.
Check the IP properties of the network connection on that device.
b.
Try to re−run these basic tests from that device in order to locate the loss of connectivity.
c.
Data Rate Mismatch
Wireless bridges can run into connectivity issues if you configure the bridges with sub−optimal or incorrect
data rate settings. If you configure the data rates incorrectly on wireless bridges, the bridges fail to
communicate.
data rate settings. If you configure the data rates incorrectly on wireless bridges, the bridges fail to
communicate.
A typical example is a scenario where one of the bridges is configured for a fixed data rate, such as 11 Mbps,
and the other bridge is configured with a data rate of 5 Mbps. Normally, the bridge attempts to transmit at the
highest data rate set to basic, also called require, on the browser−based interface. In case of obstacles or
interference, the bridge steps down to the highest rate that allows data transmission. If one of the two bridges
has a data rate of 11 Mbps set, and the other is set to use any rate, the two units communicate at 11 Mbps.
However, in case of some impairment in the communication that requires the units to fall back to a lower data
rate, the unit set for 11 Mbps cannot fall back. Therefore, communications fail.
and the other bridge is configured with a data rate of 5 Mbps. Normally, the bridge attempts to transmit at the
highest data rate set to basic, also called require, on the browser−based interface. In case of obstacles or
interference, the bridge steps down to the highest rate that allows data transmission. If one of the two bridges
has a data rate of 11 Mbps set, and the other is set to use any rate, the two units communicate at 11 Mbps.
However, in case of some impairment in the communication that requires the units to fall back to a lower data
rate, the unit set for 11 Mbps cannot fall back. Therefore, communications fail.
This is one of the most common problems that relates to data rates. The workaround is to use optimized data
rate settings on the two wireless bridges.
rate settings on the two wireless bridges.
Intermittent Connectivity Issues in Wireless Bridges
There are several factors that can result into intermittent connectivity issues. These are some of the common
factors:
factors:
Radio Frequency Interference (RFI)
1.
Fresnel Zone and Line of Sight (LOS) issues
2.
Problems with Antenna Alignment
3.
Clear Channel Assessment (CCA) Parameter
4.
Other issues that degrade the performance of wireless bridges
5.
Refer to Intermittent Connectivity Issues in Wireless Bridges for more information about these factors.
Poor Throughput
Problems with bridge performance are the most difficult to troubleshoot because there are so many variables
involved. In the case of wireless products, the majority of variables are literally invisible. Bridges have tools
built into their software that can help to accurately determine the cause of symptoms of poor throughput, but
they might not be able to solve the underlying problem. As a basic approach to troubleshoot this problem, you
can increase the transmit power on the non−root bridge. Also, if the distance between the root and non−root
bridge is less than 1km, you can set the distance on the root bridge to 1. Therefore, an increased throughput
can be obtained.
involved. In the case of wireless products, the majority of variables are literally invisible. Bridges have tools
built into their software that can help to accurately determine the cause of symptoms of poor throughput, but
they might not be able to solve the underlying problem. As a basic approach to troubleshoot this problem, you
can increase the transmit power on the non−root bridge. Also, if the distance between the root and non−root
bridge is less than 1km, you can set the distance on the root bridge to 1. Therefore, an increased throughput
can be obtained.
Remember that the IEEE 802.11b protocol specifies 11 megabits per second, half−duplex, wireless
communications. Set your throughput expectations accordingly.
communications. Set your throughput expectations accordingly.
Software
The first step to troubleshoot any problem is to check the version of the software on the bridge.