Adding a Layer 2 Interface to a SEP Segment and Configuring a Role for the Interface

Context

To ensure that SEP packets are forwarded correctly in a SEP segment, add Layer 2 interfaces to the SEP segment and configure different roles for the interfaces.

After an interface is added to a SEP segment, the interface sets its interface role to the primary edge interface if the interface has the right to participate in primary edge interface election. Then, the interface periodically sends a primary edge interface election packet without waiting for the success of neighbor negotiations.

A primary edge interface election packet contains the interface role (primary edge interface, secondary edge interface, or common interface), bridge MAC address of the interface, interface ID, and integrity of the topology database.

Table 1 lists interface roles.

**Table 1** Interface roles
Interface Role	Sub-role	Description	Deployment Scenario
Common interface	-	In a SEP segment, all interfaces except edge interfaces and blocked interfaces are common interfaces. A common interface monitors the status of a directly-connected SEP link. When the link status changes, the interface sends a topology change notification message to notify its neighbors. Then the topology change notification message is flooded on the link until it finally reaches the primary edge interface. The primary edge interface determines how to process the link change.	-
Edge interface	Primary edge interface	A SEP segment has only one primary edge interface, which is determined by the configuration and election. The primary edge interface initiates blocked interface preemption, terminates packets, and sends topology change notification messages to other networks.	Open ring networking Closed ring networking Multi-ring networking Hybrid SEP+RRPP ring networking
	Secondary edge interface	A SEP segment has only one secondary edge interface, which is determined by the configuration and election. The secondary edge interface terminates packets and sends topology change notification messages to other networks.
	No-neighbor primary edge interface	An interface at the edge of a SEP segment is a no-neighbor edge interface, which is determined by the configuration and election. The no-neighbor primary edge interface terminates packets and sends topology change notification messages to other networks. No-neighbor primary edge interfaces are used to interconnect Huawei devices and non-Huawei devices or interconnect Huawei devices and devices that do not support SEP.	Hybrid SEP+MSTP ring networking
	No-neighbor secondary edge interface	The no-neighbor secondary edge interface terminates packets and sends topology change notification messages to other networks. No-neighbor secondary edge interfaces are used to interconnect Huawei devices and non-Huawei devices or interconnect Huawei devices and devices that do not support SEP.	Hybrid SEP+MSTP ring networking

It is not recommended to configure primary edge interfaces and no-neighbor edge interfaces in the same SEP segment. It is not recommended to configure secondary edge interfaces and no-neighbor edge interfaces in the same SEP segment.
Before adding a Layer 2 interface to a SEP segment, ensure that STP has been disabled on the interface (except that the interface is a no-neighbor edge interface).
Before adding an interface to a SEP segment, disable Smart Link on the interface.
Before adding an interface to a SEP segment, disable port security on the interface; otherwise, loops cannot be prevented.

Procedure

Run system-view
The system view is displayed.
Run interface interface-type interface-number
The view of an Ethernet interface added to the SEP segment is displayed.
Run port link-type { trunk | hybrid }
The link type of the interface is set to trunk or hybrid.
Run stp disable
STP is disabled on the interface.
Run sep segment segment-id [ edge [ no-neighbor ] { primary | secondary } ]
The Ethernet interface is added to a specified SEP segment and a role is configured for the interface.

An interface can be added to a maximum of two SEP segments.