Guidelines For Software-Controlled Redundant Ports And Port Groups - Extreme Networks ExtremeWare XOS Guide Manual

Configuring Slots and Ports on a Switch
Figure 1: Dual-homed implementation for switch C
Switch A
Primary
Link
In normal operation, the primary port is active and the software redundant switch (switch C in
Figure 1) blocks the redundant port for all traffic, thereby avoiding a loop in the network. If the switch
detects that the primary port is down, the switch unblocks the redundant port and allows traffic to flow
through that redundant port.
NOTE
The primary and redundant ports must have identical VLAN membership.
You configure the software-controlled redundant port feature either to have the redundant link always
physically up but logically blocked or to have the link always physically down. The default value is to
have the link physically down, or Off.
By default, Smart Redundancy is always enabled. If you enable Smart Redundancy, the switch
automatically fails over to the redundant port and returns traffic to the primary port once connectivity
is restored on that port. If you do not want the automatic restoration of the primary link when it
becomes active, disable Smart Redundancy.
Guidelines for Software-Controlled Redundant Ports and Port
Groups
Software-controlled redundant ports and port groups have the following limitations:
You cannot have any Layer 2 protocols configured on any of the VLANs that are present on the
●
ports. (You will see an error message if you attempt to configure software redundant ports on ports
with VLANs running Layer 2 protocols.)
The primary and redundant ports must have identical VLAN membership.
●
The master port is the only port of a load-sharing group that can be configured as either a primary
●
or redundant port. Also, all ports on the load-sharing group must fail before the software-controlled
redundancy is triggered.
You must disable the software redundancy on the master port prior to enabling or disabling load
●
sharing.
You can configure only one redundant port for each primary port.
●
Recovery may be limited by FDB aging on the neighboring switch for unidirectional traffic. For bi-
●
directional traffic, the recovery is immediate.
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Switch B
Redundant
Link
Switch C
XOS002
ExtremeWare XOS 11.3 Concepts Guide