D-Link DES-6300, User Manual, Page: 35 / 298

Modular L3 Ethernet Switch User’s Guide
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Illustration of STA
A simple illustration of three Bridges (or the Switch) connected in a loop is depicted in Figure 5-
1 . In this example, you can anticipate some major network problems if the STA assistance is not
applied. For instance, if Bridge 1 broadcasts a packet to Bridge 2, Bridge 2 will broadcast it to
Bridge 3, and Bridge 3 will broadcast it to Bridge 1 and so on. The broadcast packet will be
passed indefinitely in a loop, causing a serious network failure.
To alleviate network loop problems, STA can be applied as shown in
Figure 5-2 . In this
example, STA breaks the loop by blocking the connection between Bridge 1 and 2. The decision
to block a particular connection is based on the STA calculation of the most current Bridge and
Port settings. Now, if Bridge 1 broadcasts a packet to Bridge 3, then Bridge 3 will broadcast it to
Bridge 2 and the broadcast will end there.
STA setup can be somewhat complex. Therefore, you are advised to keep the default factory
settings and STA will automatically assign root bridges/ports and block loop connections.
However, if you need to customize the STA parameters, refer to
Table 5-1 .
Figure 5- 1. Before Applying the STA Rules
Figure 5- 2. After Applying the STA Rules