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Bypass Relay Function
The TN-5816A/5818A is equipped with a bypass relay function. When the
switch is operating normally, these bypass ports work in the same way as
the other ports. That is, frame ingressions are processed and then
forwarded. If the switch stops working due to a power failure, the bypass
relay function will be triggered to ensure non-stop data communication.
The figure below illustrates the bypass relay function. For example, if
Switch B loses power, then the two Gigabit ports will be bypassed through
the relay circuit and the transmission line from Switch A to B and the
transmission line from Switch B to C will interconnect automatically,
ensuring that power continues to be supplied.
The bypass relay function helps the network recover from single-node
failures in a linear topology.
Since the maximum segment length of category 5 twisted-pair cable is
100 meters, cable length must be considered when designing a network
that utilizes this function. For example, the total length of the cables from
Switch A to B and from B to C must be no more than 100 meters. This way,
if the two adjacent nodes (switch B and C for example) encounter a power
failure, there will be no stoppage, provided that the total length of the
cables A-to-B, B-to-C, and C-to-D are no more than 100 meters.
The bypass relay function works best for networks with linear topologies.
ToughNet™ switches with bypass relay function are not recommended to
be used in networks that employ ring topologies because network loops
may occur when redundancy protocols such as RSTP or TurboRing™ are
applied.
Bypassing
Switch A
Switch B
Switch C
Switch D
