Huawei AR530 series Configuration Manual page 300

Huawei AR530&AR550 Series Industrial Switch Routers
Configuration Guide - Ethernet Switching
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Issue 01 (2014-11-30)
Interface Blocking Mode
Specify a blocked interface
based on the device and
interface names.
Preemption
After the interface blocking mode is specified, whether a specified interface will be blocked
is determined by the preemption mode.
Table 8-6 Preemption mode
Preemption Mode
Non-preemption mode
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Description
After SEP is configured, the interface to be blocked is
determined by the device and interface names. Before
specifying an interface to block, run the display
command to view the current ring topology and all
interfaces, and then specify the device and interface
names.
If multiple interfaces on the ring have the same device
and interface names, SEP blocks the interface nearest to
the primary edge interface in the topology.
NOTE
If you change the device name or interface name after
specifying the interface to block, the interface cannot preempt
to be the blocked interface.
Table 8-6 lists the preemption modes.
Description
When all link faults are rectified or the last two interfaces
enabled with SEP complete neighbor negotiations,
interfaces send blocking status packets to each other.
The interface with the highest priority is then blocked,
and the other interfaces enter the Forwarding state.
8 SEP Configuration
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