Establishing the EVC Model

Usage Scenario

Traditional Ethernet access models have the drawbacks:

• Service access point

  Sub-interfaces and Layer 2 physical interfaces, which have various types and require different configurations.

• Broadcast domains

  • Virtual local area network (VLAN) for traditional Layer 2 services

    VLANs are used as broadcast domains on MANs. The VLAN tag field defined in IEEE 802.1Q has 12 bits and identifies only a maximum of 4096 VLANs.

    QinQ was developed to address the shortage of VLAN ID resources. However, QinQ must be used with the virtual private LAN service (VPLS) to provide local switching services, and QinQ cannot implement local switching services and Layer 3 access at the same time.

  • Virtual switching instance (VSI) for VPLS services

    • A customer can plan VLANs and traffic within a VSI.
    • When VLAN services are carried within a VSI, the VLANs are not isolated, posing security risks. If the same MAC address exists in multiple VLANs of a VSI, MAC address flapping occurs, affecting services.

To overcome the drawbacks, the NetEngine 8000 F implements the EVC model. The EVC model is established to forward Layer 2 services.

Pre-configuration Tasks

Before establishing the EVC model, connect interfaces between devices and set interface parameters so that the physical status of the interfaces can be up.