running SEP immediately unblocks the interface and performs link switching to restore
communication between nodes.
shows a typical SEP application. CE1 is connected to Network Provider Edges
(NPEs) through a semi-ring formed by Routers. A VRRP group is deployed on the NPEs.
Initially, NPE1 serves as the master and NPE2 as backup to NPE1. When the link between NPE1
and Router5 or a node on the link becomes faulty, NPE1 becomes the backup to NPE2, which
then becomes the master. The following situations occur depending on whether SEP is deployed.
The following assumes that the link between Router1 and Router5 becomes faulty.
l
If SEP is not deployed on the semi-ring, CE1 traffic is still transmitted along the original
path, but NPE1 does not forward traffic, causing traffic interruption.
l
If SEP is deployed on the semi-ring, the blocked interface on Router5 is unblocked, enters
the Forwarding state, and sends link state advertisements (LSAs) to instruct other nodes on
the SEP segment to update their LSA databases. Then CE1 traffic is transmitted along
backup link Router5->Router2->Router4->NPE2, ensuring uninterrupted traffic
transmission.
Huawei AR530&AR550 Series Industrial Switch Routers
Configuration Guide - Ethernet Switching
8 SEP Configuration
Issue 01 (2014-11-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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