User's Manual

6 Configuring a Wireless Backhaul
134 Installation and User Guide: Airgo Access Point
ports on radios, and bridging functions such as address learning, packet forwarding, and spanning
tree protocol (STP).
Use of Radios for Backhaul
Each access point in a backhaul configuration must have two radios and be enrolled in the
network.
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Typically, one of the radios operates in normal (AP) mode to serve downstream access
point radios or laptop clients. The other assumes the backhaul point (BP) role, relaying network
traffic upstream from laptop clients or other access point BP radios.
A radio or radios can be configured to operate in the BP mode even if its AP is directly connected
to the wired network, as in the case of building-to-building bridge applications.
Radio Bands and Backhaul Hops
Figure 97 illustrates how the AP and BP radios operate in a backhaul arrangement. For a BP radio
to establish a link with an upstream access point, it must be able to receive radio signals from the
AP radio in the upstream access point. Accordingly, the node with the BP radio must be within
range of the upstream AP radio.
Figure 97: AP and BP Radios in Backhaul Arrangement
To prevent interference from compromising communications, the radios on each access point must
operate in different bands. If the AP radio operates in the 2.4GHz band, then the BP radio must
operate in the 5GHz band, and vice versa. As the number of hops increases, this creates an
alternating band pattern (Figure 98).
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Each access point must have a wired connection to be enrolled in the network (see “Enrolling APs” on page 181). After the
AP is enrolled, the wired connection can be removed.
10/100 Switched Ethernet
AP Radio
AP Radio
Client Client
BP Radio
Security Portal AP
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