Overview ERPS

STP (Spanning Tree Protocol) is generally used for network reliability in Ethernet L2 networks, but STP (Spanning Tree Protocol) usually converges in seconds, and the convergence time is longer when the network diameter is larger. In order to shorten the convergence time and eliminate the influence of the network size, ERPS (Ethernet Ring Protection Switching) technology came into being. ERPS (Ethernet Ring Protection Switching) is a L2 protocol standard defined by ITU-T, and the protocol standard number is ITU-T G.8032/Y1344, also known as G.8032. G. 8032 is a link layer technology of Ethernet ring network with high reliability and stability. It can prevent the broadcasting storm caused by the data loop when the Ethernet ring network is intact. When the link of the Ethernet ring network fails, it can quickly restore the communication path between the nodes on the ring network, and has a high convergence speed. Meanwhile, if the equipment of the manufacturers in the ring network supports the protocol, they can communicate with each other..

ERPS related concepts:

• ERPS (Ethernet Ring Protection Switching) Ring: ERPS Ring is the basic unit of the ERPS protocol. It consists of a group of the interconnected network devices with the same control VLAN (Virtual Local Area Network). ERPS rings are divided into main rings and sub-rings. The main rings are closed rings and the sub-rings are non-closed rings. The attributes of the main and sub-rings are determined by the user.
• Port role: There are three types of port roles specified in the ERPS protocol: RPL owner port, RPL neighbor port and common port, among which RPL neighbor port type is only supported by ERPSv2 version.
• RPL owner port: An ERPS ring has only one RPL owner port, which is specified by the user configuration. ERPS protocol prevents the link from generating loops by blocking the forwarding status of the RPL owner port. The link where the RPL owner port is located is the RPL (Ring Protection Link).
• RPL neighbor port: RPL neighbor port refers to the node port directly connected to the RPL owner port. Normally, both RPL owner ports and RPL neighbor ports are blocked to prevent loops. When ERPS ring network fails, RPL owner port and RPL neighbor port will be opened.
• Ordinary port: In ERPS ring, all ports except RPL owner port and RPL neighbor port are ordinary ports. Ordinary ports are responsible for monitoring their own direct-connected link status, and timely notifying other node ports of link status changes.
• ERPS Controls VLAN: Used to transmit ERPS protocol packets. The control VLAN is specified by the user. The VLAN used as ERPS control VLAN cannot be used by other services. The control VLAN of each ERPS loop is different.
• ERPS data instance: The data instance of data VLAN mapping that needs the ERPS ring protection.