Specifications

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Cisco MWR 2941 Mobile Wireless Edge Router Release 3.5 Software Configuration Guide, Cisco IOS Release 15.1(3)MR
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Chapter 14 Configuring Resilient Ethernet Protocol
Configuring Resilient Ethernet Protocol (REP)
• Default REP Configuration, page 14-7
• REP Configuration Guidelines, page 14-7
• Configuring the REP Administrative VLAN, page 14-8
• Configuring REP Interfaces, page 14-10
• Setting Manual Preemption for VLAN Load Balancing, page 14-13
• Configuring SNMP Traps for REP, page 14-14
• Monitoring REP, page 14-15
Default REP Configuration
REP is disabled on all interfaces. When enabled, the interface is a regular segment port unless it is
configured as an edge port.
When REP is enabled, the sending of segment topology change notices (STCNs) is disabled, all VLANs
are blocked, and the administrative VLAN is VLAN 1.
When VLAN load balancing is enabled, the default is manual preemption with the delay timer disabled.
If VLAN load balancing is not configured, the default after manual preemption is to block all VLANs
at the primary edge port.
REP Configuration Guidelines
Follow these guidelines when configuring REP:
• We recommend that you begin by configuring one port and then configure the contiguous ports to
minimize the number of segments and the number of blocked ports.
• If more than two ports in a segment fail when no external neighbors are configured, one port goes
into a forwarding state for the data path to help maintain connectivity during configuration. In the
show rep interface privileged EXEC command output, the Port Role for this port shows as Fail
Logical Open; the Port Role for the other failed port shows as Fail No Ext Neighbor. When the
external neighbors for the failed ports are configured, the ports go through the alternate port state
transitions and eventually go to an open state or remain as the alternate port, based on the alternate
port election mechanism.
• REP ports must be Layer 2 trunk ports.
• Be careful when configuring REP through a Telnet connection. Because REP blocks all VLANs
until another REP interface sends a message to unblock the VLAN, you might lose connectivity to
the router if you enable REP in a Telnet session that accesses the router through the REP interface.
• You cannot run REP and STP or REP and Flex Links on the same segment or interface.
• If you connect an STP network to the REP segment, be sure that the connection is at the segment
edge. An STP connection that is not at the edge could cause a bridging loop because STP does not
run on REP segments. All STP BPDUs are dropped at REP interfaces.
• You must configure all trunk ports in the segment with the same set of allowed VLANs, or a
misconfiguration occurs.
• REP ports follow these rules:
– There is no limit to the number of REP ports on a switch; however, only two ports on a switch
can belong to the same REP segment.