In a SEP segment, a SEP interface has two working states: Forwarding and Discarding, as
shown in
.
Table 8-2
Interface status
Interface
Status
Description
Forwarding The interface can forward user traffic, receive and send SEP packets.
Discarding
The interface can receive and send SEP packets but cannot forward user
traffic.
An interface may be in Forwarding or Discarding state regardless of its role.
SEP Packet
shows the types of SEP packets.
Table 8-3
Types of SEP packets
Packet Type
Packet Subtype Description
Hello packet
-
After an interface is added to a SEP segment, neighbor
negotiations start. The interface and its neighbor
exchange Hello packets to establish a neighbor
relationship. After neighbor negotiations succeed, the
two interfaces continue to exchange Hello packets to
detect their neighbor status.
LSA
LSA request
packet
After an interface has SEP enabled, the interface
periodically sends LSAs to its neighbor. After the state
machine of the neighbor goes Up, the two interfaces
update their LSA databases, that is, all topology
information.
LSA ACK packet
TC packet
-
When the topology of a SEP segment changes, the
device where the SEP segment and the upper-layer
network are intersected sends a Topology Change (TC)
packet to notify the upper-layer network. Then all
nodes on the upper-layer network need to update their
MAC address tables and ARP tables.
GR packet
-
When a device is performing an active/standby
switchover, it sends a SEP Graceful Restart (GR)
packet to instruct other nodes to prolong the aging time
of the LSAs received from the device. After the active/
standby switchover is complete, the device needs to
send another GR packet to instruct other nodes to
restore the aging time of the LSAs received from the
device to the previous value.
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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