Hello, everyone!
Definition
VLAN is a communications technology that divides a physical LAN into multiple logical broadcast domains (multiple VLANs). NEs in a VLAN can communicate with each other but NEs in different VLANs cannot.
Purpose
VLAN allows packets to be broadcast only within a single VLAN, preventing bandwidth waste caused by broadcast storms. Furthermore, VLAN enhances network security, because NEs in different VLANs cannot communicate with each other directly.
For example, for users of different enterprises in the same office building, it is too costly to build separate LANs for each enterprise, and insecure if the enterprises are to share the existing LAN of the building. VLAN resolves this dilemma.
Figure 2-1 VLAN application
Make different enterprise users belonging to different VLANs. In this way, the enterprise users share the LAN facilities and at the same time, each has their own secure networks.
Configuring a VLAN
Creating a VLAN
Creating VLAN is a prerequisite for configuring a VLAN or service. Hence, before configuring a VLAN, make sure that the VLAN creating based on planning is complete.Configuring the VLAN attribute
Configuring the VLAN attribute is a prerequisite for configuring a VLAN. Hence, before configuring a service, make sure that the VLAN configuration based on planning is complete.Configuring Upstream Port of a VLAN
The upstream port on an access device connects to the upper layer device to forward access device data to the upstream network and forward upper layer device data to users.Configuring a VLAN Service Profile
A VLAN service profile is a collection of service-related parameters for VLAN attributes. After a VLAN is bound to a VLAN service profile, the VLAN has all the VLAN attributes defined in the VLAN service profile. Binding a VLAN service profile is an efficient way of configuring a VLAN.Example: Configuring the QinQ VLAN
The QinQ-VLAN-based private line service can achieve interconnection and secure communication among branches in different areas within the enterprise private network.Example: Configuring VLAN Stacking Multi-ISP Wholesale Access
In a Layer-2 switching metropolitan area network (MAN), there are multiple Internet service providers (ISPs). To provision the services provided by the ISP to the specified user group rapidly, the outer VLAN tags of VLAN stacking can be used to identify ISPs, while the inner VLAN tags to identify users. In this way, different user groups can be connected to the specified ISPs in batches through different outer VLAN tags to obtain services from the ISPs.
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