This MIB module defines objects required for managing
Resilient Ethernet Protocol (REP).
Resilient Ethernet Protocol (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.
The following diagram depicts a REP segment:
[Sw E1]E---NE[Sw 1]NE---NE[Sw 2]NE.........
[Sw E2]E---NE[Sw N]NE---NE[Sw N-1]NE.......
Sw : Switch.
E : Edge port.
NE : Non-Edge port.
E1/E2: Edge switches. E1 and E2 can either be same or
A REP segment is a chain of ports connected to each other
and configured with a segment identifier. Each segment
consists of standard (non-edge) segment ports and up to
two edge ports. A device can have only two ports that
belong to the same segment, and each segment port can have
only one external neighbor.
One edge port in a REP segment acts as the primary edge
port; the other as the secondary edge port. It is the primary
edge port that always participates in VLAN load balancing in
a REP segment. REP VLAN load balancing is achieved by blocking
some VLANs at a configured alternate port and all other VLANs at
an edge port. The execution (preemption) of VLAN load balancing
is triggered by manually enforcing it or after a pre-defined
delay, after the REP segment is complete.
When segment is completed, all ports will be in open state
except one port that can be in alternate state that is used for
VLAN load balancing as explained above.