Rockwell Automation 1783-BMxxx Stratix 5700 Ethernet Managed Switches User Manual - Manual (Page 108)

108 Rockwell Automation Publication 1783-UM004E-EN-P - June 2014
Chapter 3 Switch Software Features
REP and STP can coexist on the same switch, but not on the same port. REP
does not interact with STP. For example, if a port is configured as an REP port,
STP is disabled on that port. STP bridge protocol data units (BPDUs) are not
accepted on or sent from REP ports. However, adjacent REP and STP rings or
domains can share a common link. This common link can be used for passing
REP and STP date plane traffic, or for the STP control plane traffic.
Figure 6 shows an example of a segment consisting of six ports spread across four
switches. Ports E1 and E2 are configured as edge ports. When all ports are
operational (as in the segment on the left), a single port is blocked, shown by the
diagonal line. When there is a failure in the network, as shown in the diagram on
the right, the blocked port returns to the forwarding state to minimize network
disruption.
REP Open Segment
The segment shown in Figure 6 is an open segment. There is no connectivity
between the two edge ports. The REP segment cannot cause a bridging loop and
it is safe to connect the segment edges to any network. All hosts connected to
switches inside the segment have two possible connections to the rest of the
network through the edge ports, but only one connection is accessible at any
time. If a failure causes a host to be unable to access its usual gateway, REP
unblocks all ports to make sure that connectivity is available through the other
gateway.
In the following example, E1 or E2 can be configured as the primary edge port.
Figure 6 - Open Segment Example
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Edge Port
Blocked Port
Link Failure
E1 E1 E2 E2
E1