The Smart Ethernet Protection (SEP) protocol is a link layer protocol dedicated to Ethernet rings. SEP takes an SEP segment as a basic unit. An SEP segment is composed of multiple interconnected Layer 2 switching devices configured with the same SEP segment ID and the same control VLAN ID.
Generally, redundant links are used on an Ethernet switching network to provide link backup and enhance network reliability. The use of redundant links, however, may produce loops, causing broadcast storms and rendering the MAC address table unstable. As a result, the communication quality deteriorates, and communication services may even be interrupted. To solve the loop problem, Huawei datacom devices support the following ring network protocols:
STP/RSTP/MSTP
STP, RSTP, and MSTP are standard protocols for breaking loops on Ethernet networks. They are mature and widely applied. Huawei devices running one of them can communicate with non-Huawei devices. The convergence time is at the second level on a network running STP, RSTP, or MSTP, which cannot meet the requirements of some real-time services. The convergence time is affected by the network topology.
RRPP
RRPP is a propriety protocol of Huawei. It features short convergence time (less than 50 ms) and supports load balancing for different types of traffic. A Huawei device running RRPP cannot communicate with any non-Huawei device. RRPP has a high requirement on network topologies. Logical topologies need to be configured for a physical topology, and primary rings and sub-rings need to be defined for these logical topologies. Therefore, RRPP is not applicable to complex networks.
Therefore, Huawei develops SEP. Like RRPP, SEP boasts short convergence time (less than 50 ms). Compared with RRPP, SEP has the following advantages:
SEP supports various types of networking modes. For example, a network running SEP can communicate with a network running STP, RSTP, MSTP, or RRPP. SEP supports all topologies and the display of network topologies.
The blocked interface, therefore, can be quickly located. When a fault occurs, SEP can quickly locate the fault, improving network maintainability.
SEP supports various policies for specifying an interface to block. This allows the implementation of traffic load balancing.
Link switchback is not performed after fault recovery, improving network stability.
You can check more in
https://actfornet.com/kb/-huawei-smart-ethernet-protection-(sep)-technology-white-paper_408.html
