Which of the following statements regarding two-layer MPLS labels is false?

Which of the following statements regarding two-layer MPLS labels is false?

• A. The outer label is the private network label.
• B. The MPLS VPN outer label is distributed manually by the LDP protocol.
• C. The outer label in data packets is always retained for forwarding.
• D. The outer label instructs the PE to send data packets to the correct VPN.

Answer: (C)

The statement that the outer label in data packets is always retained for forwarding is indeed inaccurate. In a two-layer MPLS (Multiprotocol Label Switching) architecture, the outer label is typically assigned to identify the correct VPN and to route packets through the provider's core network. However, once the packet reaches the egress Provider Edge (PE) router, this outer label is removed before the packet is forwarded to the appropriate customer network. This process is known as "label popping," and it is essential for ensuring that the packet is delivered to the correct end-user destination without any MPLS labels. The other statements accurately reflect the nature of MPLS. The outer label is indeed associated with the private network label specific to a VPN, and it is provided to facilitate proper forwarding. The distribution of the outer label is often handled manually or configured using protocols like LDP (Label Distribution Protocol), which effectively manages label binding and allocation within the MPLS framework. Finally, the outer label's primary role is to ensure that packets are routed correctly to the intended VPN, demonstrating its critical function in maintaining the integrity of VPN communications across the MPLS backbone.

The statement that the outer label in data packets is always retained for forwarding is indeed inaccurate. In a two-layer MPLS (Multiprotocol Label Switching) architecture, the outer label is typically assigned to identify the correct VPN and to route packets through the provider's core network. However, once the packet reaches the egress Provider Edge (PE) router, this outer label is removed before the packet is forwarded to the appropriate customer network. This process is known as "label popping," and it is essential for ensuring that the packet is delivered to the correct end-user destination without any MPLS labels.

The other statements accurately reflect the nature of MPLS. The outer label is indeed associated with the private network label specific to a VPN, and it is provided to facilitate proper forwarding. The distribution of the outer label is often handled manually or configured using protocols like LDP (Label Distribution Protocol), which effectively manages label binding and allocation within the MPLS framework. Finally, the outer label's primary role is to ensure that packets are routed correctly to the intended VPN, demonstrating its critical function in maintaining the integrity of VPN communications across the MPLS backbone.