You are recommending HPE Aruba CX switches to a service provider for a Metro Ethernet solution. Which technology is the customer likely to require to allow each customer to stretch multiple VLANs…

Question

Options

• AVMware NSX integration
• BRDMA over Converged Ethernet (RoCE)
• CData Center Bridging (DCB)
• DQinQ

• C
  5% (1)
• D
  95% (18)

Explanation

QinQ (IEEE 802.1ad) - also called VLAN stacking or double tagging - solves exactly this problem: it wraps a customer's existing 802.1Q VLAN tag inside an outer service provider VLAN tag, letting multiple customers each carry their own full range of VLANs across a shared Metro Ethernet infrastructure without tag conflicts.

Why the distractors are wrong:

• A (VMware NSX): NSX is a software-defined networking overlay for virtualized data centers - it has no relevance to a service provider's Metro Ethernet transport layer.
• B (RoCE): RDMA over Converged Ethernet is a low-latency storage/HPC networking protocol for moving data between servers; it has nothing to do with VLAN multiplexing across a WAN.
• C (DCB): Data Center Bridging is a suite of IEEE enhancements (PFC, ETS, etc.) for lossless Ethernet in storage and HPC environments - again, unrelated to VLAN tunneling across a Metro Ethernet link.

Memory tip: Think of QinQ as a "VLAN inside a VLAN" - like putting a customer's envelope inside the service provider's envelope. The Q stands for the 802.1Q standard, and double-Q = QinQ. Whenever an exam mentions stretching customer VLANs across a provider network, QinQ is the answer.

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