Configuring a VXLAN Service Access Point

Layer 2 sub-interfaces are used for service access on VXLANs. These Layer 2 sub-interfaces can have different encapsulation types configured to transmit various types of data packets. A bridge domain (BD) is a broadcast domain. After a Layer 2 sub-interface is associated with a BD, the sub-interface can transmit data packets through this BD.

Context

As shown in Table 1, Layer 2 sub-interfaces can have different encapsulation types configured to transmit various types of data packets.

**Table 1** Traffic encapsulation types
Traffic Encapsulation Type	Description
dot1q	This type of sub-interface accepts only packets with a specified tag. The dot1q traffic encapsulation type has the following restrictions: The VLAN ID encapsulated by a Layer 2 sub-interface cannot be the same as that allowed to pass by the Layer 2 interface where the sub-interface resides. The VLAN IDs encapsulated by a Layer 2 sub-interface and a Layer 3 sub-interface cannot be the same.
untag	This type of sub-interface accepts only untagged packets. The untag traffic encapsulation type has the following restrictions: The physical interface where the sub-interface resides must have only default configurations. Only Layer 2 physical interfaces and Layer 2 Eth-Trunk interfaces can have untag Layer 2 sub-interfaces created. Only one untag Layer 2 sub-interface can be created on a main interface.
default	This type of sub-interface accepts all packets, irrespective of whether the packets carry VLAN tags. The default traffic encapsulation type has the following restrictions: The interface where the sub-interface resides must not be added to any VLAN. Only Layer 2 physical interfaces and Layer 2 Eth-Trunk interfaces can have default Layer 2 sub-interfaces created. If default is configured for a Layer 2 sub-interface on a main interface, the main interface cannot have other types of Layer 2 sub-interfaces configured.
qinq	Packets received by this type of sub-interface carry two or more VLAN tags. The sub-interface determines whether to accept the packets based on the innermost two VLAN tags.

Configure a service access point on a Layer 2 gateway:

Procedure

Run system-view
The system view is displayed.
Run bridge-domain bd-id
A BD is created, and the BD view is displayed.
(Optional) Run description description
A description is configured for the BD.
Run quit
Return to the system view.
Run interface interface-type interface-number.subnum mode l2
A Layer 2 sub-interface is created, and the sub-interface view is displayed.

Before running this command, ensure that the Layer 2 main interface does not have the port link-type dot1q-tunnel command configuration. If the configuration has existed, run the undo port link-type command to delete it.
Run encapsulation { dot1q [ vid vid ] | default | untag | qinq [ vid pe-vid ce-vid { low-ce-vid [ to high-ce-vid ] } ] }
A traffic encapsulation type is specified for the Layer 2 sub-interface.
Run rewrite pop { single | double }
The sub-interface is enabled to remove single or double VLAN tags from received packets.

If the received packets each carry a single VLAN tag, specify single.

If the traffic encapsulation type is specified as qinq in the preceding step using the encapsulation qinq vid pe-vid ce-vid { low-ce-vid [ to high-ce-vid ] | default } command, specify double.
Run bridge-domain bd-id
The Layer 2 sub-interface is added to the BD so that the sub-interface can transmit data packets through this BD.

If a default Layer 2 sub-interface is added to a BD, no BDIF interface can be created for the BD.
Run commit
The configuration is committed.