Epsr Protocol - Allied Telesis SwitchBlade x3100 Series Manual

Introduction
The rate at which the EPSR protocol Health control message is sent by the master node for this EPSR
domain.
FailoverTime
•
Time for which the master node waits before declaring that it has detected a break in the ring for this EPSR
domain.
Flap
•
The minimum number of seconds that a master node must remain in the failed state (before moving to the
complete state), even if the ring has recovered from its fault condition. This delay is to limit unnecessary
blocking and unblocking of the secondary port when a link in the ring is flapping (intermittently recovering
from its fault). The default is 0.
Ringports
•
The two ports that are members of the EPSR domain.
Protected Vlan(s)
•
The vlan VIDs which require protection on the EPSR domain.
Control Vlan
•
The unique vlan VID which will be used as the control vlan for the EPSR domain.
Configuration requirements and commands will be covered in detail later in this section.
With the Allied Telesis SBx3112, if both fibers are cut on a single node, and one of the fibers is
Note:
restored, the Allied Telesis SBx3112 will recover and begin processing traffic. This applies whether the
node is a Master Node or other node on the ring. However, this scenario applies only when both ring
ports on the same node have failed. More complicated failure scenarios are handled by a specific
feature, EPSR+ and EPSR++, described in 4.6.6.

4.6.4 EPSR Protocol

The EPSR protocol is used to provide the EPSR functionality in Allied Telesis layer 2 systems. EPSR protocol
control messages are transported around the ring network for an EPSR domain via its control vlan. The mes-
sages can originate at the master node or at the transit node; however, they will always terminate at the master
node. These messages are used to provide fast protection switching, for a given EPSR domain, in the layer 2 sys-
tems interconnected to form the Ethernet ring.
An Allied Telesis system with EPSR implemented can be part of more than one ring network. As a result, there
can be more than one EPSR domain on such a system, one for each of the EPSR protected rings of which it is a
member. Note that there can also be more than one EPSR domain running in a system when it is part of only
one ring network with each domain assigned its own set of protected vlans and a control vlan managing the
bandwidth available in the ring.
4-116
Software Reference for SwitchBlade x3100 Series Switches (Layer Two Switching)
EPSR Protocol