Chapter 21 Configuring Resilient Ethernet Protocol; Understanding Rep - Cisco IE-3000-8TC Software Configuration Manual

Configuring Resilient Ethernet Protocol
This chapter describes how to use Resilient Ethernet Protocol (REP) on the IE 3000 switch. REP is a
Cisco proprietary protocol that provides an alternative to Spanning Tree Protocol (STP) to control
network loops, handle link failures, and improve convergence time. REP controls a group of ports
connected in a segment, ensures that the segment does not create any bridging loops, and responds to
link failures within the segment. REP provides a basis for constructing more complex networks and
supports VLAN load balancing.
This chapter includes these sections:
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Understanding REP

One REP segment is a chain of ports connected to each other and configured with a segment ID. Each
segment consists of standard (non-edge) segment ports and two user-configured edge ports. A switch can
have no more than two ports that belong to the same segment, and each segment port can have only one
external neighbor. A segment can go through a shared medium, but on any link only two ports can belong
to the same segment. REP is supported only on Layer 2 trunk interfaces.
Figure 21-1
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.
OL-13018-03
Understanding REP, page 21-1
Configuring REP, page 21-6
Monitoring REP, page 21-13
shows an example of a segment consisting of six ports spread across four switches. Ports E1
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Cisco IE 3000 Switch Software Configuration Guide
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21-1