D-Link DES-6300 User Manual - Illustration of Sta

Modular L3 Ethernet Switch User’s Guide

26 

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