350-501 Question #38: Real Exam Question with Answer & Explanation

Question

Which MPLS design attribute can you use to provide Internet access to a major customer through a separate dedicated VPN?

Options

• AThe customer that needs the Internet access service is assigned to the same RTs as the Internet
• BThe Internet gateway inserts the full Internet BGP routing table into the Internet access VPN
• CThe Internet gateway router is connected as a PE router to the MPLS backbone.
• DThe CE router supports VRF-Ute and the full BGP routing table.

Explanation

To provide a customer with dedicated Internet access through a separate VPN in an MPLS network, the customer's VPN must import Internet routes.

Common mistakes.

• B. The Internet gateway typically inserts its connected or learned Internet routes into its own VRF, which are then exported via RTs, rather than directly into the customer's VPN without RT matching.
• C. Connecting the Internet gateway router as a PE router is a standard setup, but it does not, by itself, explain the specific mechanism for providing Internet access to a separate dedicated VPN without involving RTs.
• D. While a CE router supporting VRF-Lite and the full BGP routing table can be part of the solution, the core MPLS design attribute for sharing Internet routes between VPNs on the PE router is the use of Route Targets, not primarily a CE router feature.

Concept tested. MPLS VPN Internet access using Route Targets

Reference. https://www.cisco.com/c/en/us/td/docs/routers/crs/software/crs_r4-2/mpls/configuration/guide/mpls_cfg_4-2/mpvpnint.html

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