Service Provider Networks: Internet service providers use Q-in-Q to segregate traffic from different customers over the same infrastructure, allowing each customer’s network traffic to be isolated and managed independently.
Large Enterprise Networks: In corporate environments with extensive network infrastructures, Q-in-Q can be used to manage traffic from different departments, offices, or tenants in a multi-tenant building, keeping their data separate and secure.
Data Center Networking: Q-in-Q is utilized in data centers for segregating traffic between different clients or services, ensuring that each client’s data remains isolated and secure even when using shared network resources.
Imagine a train system where each train car (Ethernet frame) can carry multiple containers (VLANs). Normally, each car can carry just one type of container. However, with Q-in-Q, you can put a smaller container inside a larger one. This is like having a container for ‘electronics’ inside another container labeled ‘fragile goods’. The outer container (outer VLAN tag) tells the network the general destination or category of the data, while the inner container (inner VLAN tag) specifies the exact drop-off point or data type. This system allows for more efficient use of the train cars (network bandwidth) by carrying multiple types of goods (data from different VLANs) in a single trip, without mixing them up.
