350-401 Question 506
Single answerA service provider is tasked with deploying an MPLS Layer 3 VPN to interconnect multiple customer sites. The service provider needs to ensure that customer traffic is isolated while allowing for overlapping IP address spaces between different customers. Which component of the MPLS Layer 3 VPN architecture is responsible for maintaining this isolation?
- A
Route Distinguisher (RD)
- B
Route Target (RT)
- C
VRF (Virtual Routing and Forwarding)
- D
Label Distribution Protocol (LDP)
Show answer and explanation
Correct answer: C
Explanation
In MPLS Layer 3 VPNs, VRFs are a fundamental component that provide customer traffic isolation by maintaining separate routing tables for each customer. This logical separation allows multiple customers to use overlapping IP address spaces without interference. While other components like Route Distinguisher (RD) and Route Target (RT) play important roles in route identification and route policy control, VRFs are specifically responsible for traffic isolation.
- A. Incorrect.
Route Distinguisher (RD) is used to make routes globally unique by appending a unique identifier to the customer's IP prefix, but it does not directly handle traffic isolation.
- B. Incorrect.
Route Target (RT) is used to control the import and export of routes between VRFs but does not provide traffic isolation by itself.
- C. Correct.
VRF (Virtual Routing and Forwarding) is the correct answer. VRFs allow for the segregation of routing tables on a per-customer basis, ensuring traffic isolation and enabling support for overlapping IP address spaces.
- D. Incorrect.
Label Distribution Protocol (LDP) is used for label distribution in the MPLS domain but does not handle the logical isolation of customer traffic.