Specifications

CHAPTER

14-1

Cisco MWR 2941 Mobile Wireless Edge Router Release 3.5 Software Configuration Guide, Cisco IOS Release 15.1(3)MR

OL-26895-01

Configuring Resilient Ethernet Protocol

Resilient Ethernet Protocol (REP) is a Cisco proprietary protocol that provides an alternative to

Spanning Tree Protocol (STP) to control network loops, to respond to link failures, and to 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.

The following sections describe how to configure REP:

• Understanding Resilient Ethernet Protocol, page 14-1

• Configuring Resilient Ethernet Protocol (REP), page 14-6

• Configuration Examples for REP, page 14-16

Understanding Resilient Ethernet Protocol

The following sections provide further information about REP:

• Overview

• Link Integrity

• Fast Convergence

• VLAN Load Balancing

• REP Ports

Overview

A REP segment is a chain of ports connected to each other and configured with a segment ID. Each

segment consists of standard (nonedge) segment ports and two user-configured edge ports. A switch can

have only two ports belonging 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 14-1 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 network failure, as shown in the

diagram on the right, the blocked port returns to the forwarding state to minimize network disruption.