CISCO-RESILIENT-ETHERNET-PROTOCOL-MIB
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 different switches. 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.