User manual

Publication 1783-UM003D-EN-E - December 2009 43
Chapter 2
• Transit: This port is a non-edge port in the REP segment.
• No-Neighbor Primary: This port is a primary edge port connected a
non-REP switch.
• No-Neighbor: This port is a secondary edge port connected to a
non-REP switch.
The no-neighbor edge ports contain all properties of regular edge ports.
These ports allow construction of a REP ring containing a switch that
does not support REP protocol.
• None: This port is not part of the REP segment.
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 a REP port,
STP is disabled on that port. STP bridge protocol data units (BPDUs) are not
accepted on or sent from segment ports 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.
The following figure 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 below 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 ensure that connectivity is available
through the other gateway.