R2511-HP MSR Router Series Layer 2 - LAN Switching Configuration Guide(V5)

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Configuring VLAN termination
Overview
VLAN termination assigns a VLAN-tagged packet received to the corresponding interface according to
its VLAN tags, and then the interface removes its VLAN tags, and forwards it through Layer 3 or
processes it in another way. Whether the packet is tagged before being sent out depends on the
configuration of the outgoing interface. Before sending a packet, the port adds a VLAN tag to the packet
according to the VLAN termination configuration on the port.
VLAN termination types
VLAN termination includes the following types:
• Dot1q termination—Terminates packets which carry one or more layers of VLAN tags and whose
outermost VLAN tags match the configured values. Packets sent out of a Dot1q termination interface
are single-tagged.
• QinQ termination—Terminates packets which carry two or more layers of VLAN tags and whose
outermost two layers of tags match the configured values. Packets sent out of a QinQ termination
interface are double-tagged.
The MSR series routers support only Dot1q termination.
Application scenarios
Hosts in different VLANs cannot directly communicate with each other. You can use Layer 3 routing to
allow all VLANs to communicate. To allow the specified VLANs to communicate, you can configure
VLAN termination on VLAN interfaces or Layer 3 Ethernet subinterfaces.
In Figure 42,
Host A belongs to VLAN 2, and Host B belongs to VLAN 3. After you specify Host A's
gateway IP address as 1.1.1.1/24 and Host B's gateway IP address as 1.1.2.1/24 and configure VLAN
termination, Host A and Host B can communicate through Layer 3 Ethernet subinterfaces.