Option 2-Using The Ap As A Store-And-Forward Packet Repeater; Protected Network Operation Using Multiple Access Points - GE MDS iNET Series Reference Manual

Overview
Two transceivers may be connected "back-to-back" through the LAN Ports to form a repeater station. (The
cable must be a "cross-over" Ethernet cable for this to work). This configuration is sometimes required in a
network that includes a distant Remote that would otherwise be unable to communicate directly with the
Access Point station due to distance or terrain.
The geographic location of a repeater station is especially important. A site must be chosen that allows good
communication with both the Access Point and the outlying Remote site. This is often on top of a hill,
building, or other elevated terrain from which both sites can be "seen" by the repeater station antennas. A
detailed discussion on the effects of terrain is given in 4.1.2 Site Selection.
The following paragraphs contain specific requirements for repeater systems.
Antennas
Two antennas are required at this type of repeater station—one for each radio. Measures must be taken to
minimize the chance of interference between these antennas. One effective technique for limiting interfer-
ence is to employ vertical separation. In this arrangement, assuming both are vertically polarized, one
antenna is mounted directly over the other, separated by at least 10 feet (3 Meters). This takes advantage of
the minimal radiation exhibited by most antennas directly above and below their driven elements.
Another interference reduction technique is to cross-polarize the repeater antennas. If one antenna is
mounted for polarization in the vertical plane, and the other in the horizontal plane, an additional 20 dB of
attenuation can be achieved. (Remember that the corresponding stations should use the same antenna ori-
entation when cross-polarization is used.)
Network Name
The two radios that are wired together at the repeater site must have different network names.
Option 2—Using the AP as a Store-and-Forward Packet Repeater
A wireless network can be extended through the use of an alternate arrangement using the Access Point as
a repeater to re-transmit the signals of all stations in the network. The repeater is a standard transceiver con-
figured as an Access Point, and operating in Store and Forward mode (see Figure 1-9).
Invisible place holder
Remote
Remote
LAN
Remote
Access Point
REPEATER
LAN
LAN/WAN
Remote
LAN
Figure 1-9. Typical network with store-and-forward repeater
As with the conventional repeater described in Option 1 above, the location of a store and forward repeater
is also important. A site must be chosen that allows good communication with both the Access Point and
the outlying Remote site. This can be on the top of a hill, building, or other elevated terrain from which all
sites can be "seen" by the repeater station antenna. A detailed discussion on the effects of terrain is given in
Section 4.1.2 Site Selection.

1.4.2 Protected Network Operation using Multiple Access Points

Although GE MDS transceivers have a very robust design and have undergone intensive testing before
being shipped, it is possible for isolated failures to occur. In mission-critical applications, down time can be
virtually eliminated by using some, or all, of the following configurations:
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