A customer uses VLANs in their network. They recently acquired another company and need to extend the number of VLANs to 7400 to accommodate the growth. What should you advise?

Question

Options

• AImplement an IPv6 only environment
• BEdit the /etc/network/config file, and set VLAN_LIMIT=7401
• CUpgrade the NICs to models that support RoCE
• DTransition to a VXLAN or NVGRE network configuration

• A
  6% (2)
• B
  9% (3)
• C
  3% (1)
• D
  82% (28)

Explanation

Traditional IEEE 802.1Q VLANs use a 12-bit VLAN ID field, which caps the maximum at 4094 usable VLANs - far short of the 7400 needed. VXLAN (Virtual Extensible LAN) and NVGRE (Network Virtualization using Generic Routing Encapsulation) both use 24-bit identifiers, supporting roughly 16 million virtual network segments, making them the correct solution for large-scale VLAN exhaustion.

Why the distractors are wrong:

• A (IPv6 only): IPv6 addresses IP address space exhaustion, not VLAN count limits - these are separate problems.
• B (/etc/network/config VLAN_LIMIT): This is fabricated; the 4094 ceiling is a protocol-level constraint defined by the 802.1Q standard, not a configurable OS setting.
• C (RoCE NICs): RDMA over Converged Ethernet is a high-speed, low-latency transport technology - it has nothing to do with the number of virtual networks you can create.

Memory tip: Think "4K ceiling, eXtend with VXLAN" - when your VLAN count hits the 4094 wall, VXLAN/NVGRE let you punch through it by tunneling Layer 2 over Layer 3 with a much larger identifier space.

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