Specifications

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Cisco MWR 2941 Mobile Wireless Edge Router Software Configuration Guide, Release 12.2(33)MRB
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Chapter 4 Configuring the Cisco MWR 2941 Router Using the CLI
Configuration Sequence
Configuring Resilient Ethernet Protocol (REP)
A segment is a collection of ports connected one to the other in a chain and configured with a segment
ID. To configure REP segments, you configure the REP administrative VLAN (or use the default
VLAN 1) and then add the ports to the segment using interface configuration mode. You should
configure two edge ports in the segment, one as the primary edge port and the other, by default, the
secondary edge port. A segment has only one primary edge port. If you configure two ports in a segment
as the primary edge port, for example ports on different switches, the REP selects one to serve as the
segment primary edge port. You can also optionally configure where to send segment topology change
notices (STCNs) and VLAN load balancing messages.
The following sections describe how to configure REP on the Cisco MWR 2941.
• Default REP Configuration, page 4-15
• REP Configuration Guidelines, page 4-15
• Configuring the REP Administrative VLAN, page 4-16
• Configuring REP Interfaces, page 4-17
• Setting Manual Preemption for VLAN Load Balancing, page 4-19
• Configuring SNMP Traps for REP, page 4-19
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 in order to help maintain connectivity for the data path during configuration.
• The show rep interface command output displays the Port Role of each port on the router. The Port
Role of ports in a forwarding state is displayed as Fail Logical Open; the Port Role of other failed
ports is displayed as Fail No Ext Neighbor. When the external neighbors for the failed ports are
restored, 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.