D-Link DGS-6600-48TS Configuration Guide - Page 183

When previous timer expires, RPL owner blocks RPL and sends R-APS NR, RB RB, RPL

Page 183 highlights

Volume 3 - Layer 2 Configurations Chapter Overview VLAN. And, service protected channel is used to transmit and receive service traffic which belong to multiple VLANs, called service protected VLANs. In order to avoid traffic looping in normal idle state, previous two traffic channels at one of the ring links, ring protection link (RPL), are blocked. The responsibility for setting blocking state of RPL belongs to two ring nodes of each ERP instance, one is called RPL owner. Blocking previous two traffic channels of each ERP instance shall only block or unblock the set of VLANs which include R-APS controlled VLAN and service protected VLANs. But, blocking R-APS controlled channel only prevents R-APS messages received from one ring port being forwarded to the other ring port, and transmits and receives R-APS messages are allowed. Figure 19-1 The brief ring state transition of each ERP instance is depicted below. Figure 19-2 The ERP instance is in "Idle" state and RPL between ring node A and B (RPL owner and RPL neighbor) is blocked when no detected link failure events. When link failure occurs at ring link between ring node D and E, the ring nodes which detect the link failure event blocks the failed ring port and sends a "R-APS (SF)" (SF, Signal Fail) messages to inform other ring nodes this event. When RPL owner and RPL neighbor receive R-APS (SF) messages, they unblock the RPL to keep connectivity of the Ethernet ring and ERP instance enters "Protection" state. When previous failed link has been recovered, the ring nodes which detect the link recovery event send "R-APS (NR)" (NR, No Request) messages to inform other ring nodes this event. When RPL owner receives R-APS (NR) messages, it starts the timer in order to await the required stability of recovered link. When previous timer expires, RPL owner blocks RPL and sends "R-APS (NR, RB)" (RB, RPL Blocked) messages to inform other ring nodes that RPL has blocked. When other ring nodes receive DGS-6600 Configuration Guide 183

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Volume 3 - Layer 2 Configurations
Chapter Overview
DGS-6600 Configuration Guide
183
VLAN
. And, service protected channel is used to transmit and receive service traffic which belong to
multiple VLANs, called
service protected VLANs
.
In order to avoid traffic looping in normal idle state, previous two traffic channels at one of the ring
links,
ring protection link (RPL)
, are blocked. The responsibility for setting blocking state of RPL
belongs to two ring nodes of each ERP instance, one is called
RPL owner
.
Blocking previous two traffic channels of each ERP instance shall only block or unblock the set of
VLANs which include R-APS controlled VLAN and service protected VLANs. But, blocking R-APS
controlled channel only prevents R-APS messages received from one ring port being forwarded to
the other ring port, and transmits and receives R-APS messages are allowed.
Figure 19-1
The brief ring state transition of each ERP instance is depicted below.
Figure 19-2
The ERP instance is in "Idle" state and RPL between ring node A and B (RPL owner and RPL
neighbor) is blocked when no detected link failure events.
When link failure occurs at ring link between ring node D and E, the ring nodes which detect the link
failure event blocks the failed ring port and sends a "R-APS (SF)" (SF, Signal Fail) messages to
inform other ring nodes this event. When RPL owner and RPL neighbor receive R-APS (SF)
messages, they unblock the RPL to keep connectivity of the Ethernet ring and ERP instance enters
"Protection" state.
When previous failed link has been recovered, the ring nodes which detect the link recovery event
send "R-APS (NR)" (NR, No Request) messages to inform other ring nodes this event. When RPL
owner receives R-APS (NR) messages, it starts the timer in order to await the required stability of
recovered link.
When previous timer expires, RPL owner blocks RPL and sends "R-APS (NR, RB)" (RB, RPL
Blocked) messages to inform other ring nodes that RPL has blocked. When other ring nodes receive