Chapter 8 Wireless Configuration
8.4.1.4 STP Port States
STP assigns five port states (see next table) to eliminate packet looping. A bridge port is not allowed to go directly from blocking state to forwarding state so as to eliminate transient loops.
Table 28 STP Port States
PORT | DESCRIPTIONS | |
STATES | ||
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Disabled | STP is disabled (default). | |
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Blocking | Only configuration and management BPDUs are received and processed. | |
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Listening | All BPDUs are received and processed. | |
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Learning | All BPDUs are received and processed. Information frames are | |
| submitted to the learning process but not forwarded. | |
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| |
Forwarding | All BPDUs are received and processed. All information frames are | |
| received and forwarded. | |
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8.4.2 DFS
When you choose 802.11a in Access Point mode, the NWA uses DFS (Dynamic Frequency Selection) to give you a wider choice of wireless channels.
DFS allows you to use channels in the frequency range normally reserved for radar systems. Radar uses radio signals to detect the location of objects for military, meteorological or air traffic control purposes. As long as your NWA detects no radar activity on the channel you select, you can use the channel to communicate. However, a wireless LAN operating on the same frequency as an active radar system could disrupt the radar system. Therefore, if the NWA detects radar activity on the channel you select, it automatically instructs the wireless clients to move to another channel, then resumes communications on the new channel.
8.4.3 Roaming
A wireless station is a device with an IEEE 802.11a/b/g compliant wireless interface. An access point (AP) acts as a bridge between the wireless and wired networks. An AP creates its own wireless coverage area. A wireless station can associate with a particular access point only if it is within the access point’s coverage area.
In a network environment with multiple access points, wireless stations are able to switch from one access point to another as they move between the coverage areas. This is known as roaming. As the wireless station moves from place to place, it is responsible for choosing the most appropriate access point depending on the signal strength, network utilization or other factors.
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