qNq

qNq is a network tunneling and encapsulation protocol primarily used in computer networking and network virtualization. The term "qNq" stands for "802.1Q-in-802.1Q," indicating that it encapsulates one VLAN tagging protocol within another. This encapsulation allows multiple VLAN tags to be nested within each other, facilitating complex network segmentation and virtualization.

Originally developed as part of networking standards, qNq is utilized mainly to extend VLANs across different network segments, particularly in service provider environments and data centers. It enables the transmission of Ethernet frames with double VLAN tags, which is useful for service providers offering Layer 2 VPNs (L2VPNs). By encapsulating VLAN traffic, qNq allows service providers to support multiple customers on a single physical infrastructure while maintaining separation and security.

qNq differs from other tunneling protocols such as QinQ by its ability to handle more complex VLAN nesting, making it suitable for scenarios requiring extensive network segmentation. It is often implemented on network switches and routers supporting Ethernet VPN (EVPN), and it integrates with MPLS (Multiprotocol Label Switching) networks for scalable transport.

While qNq enhances network flexibility and segmentation, it also introduces additional complexity in network management. Proper configuration and understanding of VLAN nesting are essential to avoid issues related to VLAN tagging conflicts or network loops.

Overall, qNq is a significant protocol in modern network architecture, supporting scalable and flexible VLAN management in large, multi-tenant, and service provider networks.