D-Link xStack DES-3528 Series - ERPS Settings

xStack® DES-3528/DES-3552 Series Layer 2 Managed Stackable Fast Ethernet Switch Web UI Reference Guide
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ERPS Settings
ERPS (Ethernet Ring Protection Switching) is the first industry standard (ITU-T G.8032) for Ethernet ring protection
switching. It is achieved by integrating mature Ethernet operations, administration, and maintenance (OAM) *
functions and a simple automatic protection switching (APS) protocol for Ethernet ring networks. ERPS provides
sub-50ms protection for Ethernet traffic in a ring topology. It ensures that there are no loops formed at the Ethernet
layer.
One link within a ring will be blocked to avoid a Loop (RPL, Ring Protection Link). When the failure happens,
protection switching blocks the failed link and unblocks the RPL. When the failure clears, protection switching
blocks the RPL again and unblocks the link on which the failure is cleared.
G.8032 Terms and Concepts
The ERPS ring is formed by connecting all east and west ports of the switches in the ring. Administrators have to
manually configure the blocked port to prevent the loop. See below for a detailed explanation of ERPS terms:
RPL (Ring Protection Link) – The link, designated by ERPS mechanism, that is blocked during the Idle state to
prevent loops on a Bridged ring.
RPL Owner – The node connected to RPL that blocks traffic on RPL during the Idle state and unblocks during the
Protected state.
R-APS (Ring – Automatic Protection Switching) – Protocol messages defined in Y.1731 and G.8032 used to
coordinate the protection actions over the ring through RAPS VLAN (R-APS Channel).
RAPS VLAN (R-APS Channel) – A separate ring-wide VLAN for transmission of R-APS messages.
Protected VLAN – The service traffic VLANs for transmission of normal network traffic.
Ring Topology
ERPS supports Ethernet ring topology, as shown in the diagram below:
• Single ring (a)
• Two single rings with a shared node (b)
• Multi-ring: Rings share a common link and nodes (c)
Figure 4-80 Ethernet ring topologies supported by ERPS
Sub-ring
In topology (c), multiple rings share the same physical link. Only one of the rings uses the physical link (primary ring)
while the other ring(s) will build-up virtual channels upon the physical link. Those rings, including the virtual link, will
be the sub-rings of the primary ring.
Each ring will have its own RPL owner and port, and every ring should belong to a different RAPS VLAN.
This page is used to enable the ERPS function on the Switch.
NOTE: STP and LBD should be disabled on the ring ports before enabling ERPS. ERPS cannot be
enabled before the R-APS VLAN is created, and ring ports, RPL port, and RPL owner are
configured. Note that these parameters cannot be changed when ERPS is enabled.
To view the following window, click L2 Features > ERPS Settings, as shown below: