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SM12XPA Web User Guide
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Appendix C. G.8032 Major and Sub Rings Configuration
Introduction
Ethernet Ring Protection Switching (ERPS) is a protocol defined by the International Telecommunication Union -
Telecommunication Standardization Sector (ITU-T) to prevent loops at Layer 2. With the standard number is ITU-
T G.8032, and ERPS is also called G.8032. Generally, redundant links are used on a 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. These can affect the network, where the
communication quality is not good enough, and communication services might be interrupted.
ERPS provides advantages of traditional ring network technologies such as STP/RSTP/MSTP and optimizes
detection mechanism to provide faster convergence. For example, the ERPS-enabled switch provides 50-ms
convergence for broadcast packets. See section “
for general G.8032 ERPS configuration
information.
Basic Concepts
There are some basic concepts that support ERPS Ring:
•
Ring Protection Link (RPL)
– Link designated by mechanism that is blocked during Idle state to prevent
loop on Bridged ring.
•
RPL Owner node
– Node connected to RPL that blocks traffic on RPL during Idle state and unblocks
during Protection state.
•
RPL Neighbor node
– Node connected to RPL that blocks traffic on RPL during Idle state and unblocks
during Protection state (v2).
•
Link Monitoring
– Links of ring are monitored using standard ETH CC OAM messages (CFM)
•
Signal Fail
(SF) – Signal Fail is declared when signal fail condition is detected.
•
No Request (NR)
– No Request is declared when there are no outstanding conditions (e.g., SF, etc.) on
the node.
•
Ring APS (R-APS) Messages
– Protocol messages defined in Y.1731 and G.8032.
•
Automatic Protection Switching (APS) Channel
- Ring-wide VLAN used exclusively for transmission of
OAM messages including R-APS messages.
IP Addresses
The sample configurations below use these IP addresses:
SISPM1040-582-LRT : 192.168.1.85
SISPM1040-384-LRT-C : 192.168.1.95
362W : 192.168.1.125
362E : 192.168.1.135
