Illustration Of Sta - D-Link DES-3624 Series User Manual

Stackable NWay Ethernet Switch User's Guide

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.
40 Switch Management Concepts