Extreme Networks ExtremeWare 7.2e, Installation And User Manual

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184 ExtremeWare 7.2e Installation and User Guide
Ethernet Automatic Protection Switching
Fault Detection and Recovery
EAPS fault detection on a ring is based on a single control VLAN per EAPS domain. This EAPS domain
provides protection to one or more data-carrying VLANs called protected VLANs.
The control VLAN is used only to send and receive EAPS messages; the protected VLANs carry the
actual data traffic. As long as the ring is complete, the EAPS master node blocks the protected VLANs
from accessing its secondary port.
NOTE
The control VLAN is not blocked. Messages sent on the control VLAN must be allowed into the switch
for the master node to determine whether the ring is complete.
To avoid loops in the network, the control VLAN must be NOT be configured with an IP address, and
ONLY ring ports may be added to the VLAN.
Figure 30: EAPS fault detection and protection switching
A master node detects a ring fault in one of three ways:
•
Link-down message sent by a transit node
• Ring port down event sent by hardware layers
protected VLAN A VLAN that carries data traffic through an EAPS domain. You must configure one
or more protected VLANs for each EAPS domain. (Also known as data VLAN)
Table 33: EAPS Terms (Continued)
Term Description
EW_072
S3 sends "link down"
message to
master node
Master
node
Break
in ring
Master node opens secondary port
to allow traffic to pass
S4 sends "link down"
message to master node
S 4
S 5
S 6
S 3
S 2
S 1
P S