On SW 1 and SW 2, enable loop protection on ports 25 and 26. On SW 1, enable the Tx mode on port
25, and disable the Tx mode on port 26. On SW 2, disable the Tx mode on ports 25 and 26.
Configure data as follows:
(1) Check the configurations on SW 1 and SW 2, and confirm that STP and ERPS are disabled on ports
25 and 26.
(2) On the loop protection configuration page of SW 1, enable loop protection globally, enable loop
protection on ports 25 and 26, enable the Tx mode on port 25, disable the Tx mode on port 26, and save
the configurations.
(3) On the loop protection configuration page of SW 2, enable loop protection globally, enable loop
protection on ports 25 and -26, disable the Tx mode on ports 25 and 26, and save the configurations.
(4) After the configuration is completed, connect ports 25 and 26 on the two switches to form a ring
network. On the System Info–Loop Protection Status page, you can check the status of ports that form
the ring network.
6.9
ERPS Config
Ethernet Ring Protection Switching (ERPS) is an Ethernet multi-ring protection technology defined in
ITU-TG.8032. Aiming to improve network performance and security, ERPS is an Ethernet ring
technology that becomes an important redundancy protection measure on the L2 network.
On the L2 network, STP is often used to ensure network reliability, and the loop protection protocol
may also be used. STP is a standard ring protection protocol developed by IEEE, and has been widely
used. In practice, application of STP is restricted by the network size, and the convergence time is
affected by the network topology. The convergence time of STP is generally several seconds, or longer
if the network diameter is large. The use of RSTP/MSTP can reduce the convergence time to several
milliseconds, but still cannot meet the requirements of services (such as 3G and NGN voice services)
that require a high Quality of Service (QoS). ERPS emerges to further reduce the convergence time and
eliminate the impact caused by the network size.
ERPS is a link layer protocol dedicated for the Ethernet ring. It can prevent broadcast storms caused by
data loops in an Ethernet ring. When a link on the Ethernet ring is disconnected, the backup link can be
quickly enabled to recover communication between nodes on the ring network. Compared with STP,
ERPS features a fast topology convergence speed (less than 20 ms) and the convergence time that is
independent of the number of nodes on the ring network. Loop protection is similar to STP and ERPS,
but it lacks an IEEE standard and is a private protocol. Loop protection is easy to configure and use. It
