350-501 Question #301: Real Exam Question with Answer & Explanation

Question

Refer to the exhibit. An administrator working for large ISP must connect its two POP sites to provide internet connectivity to its customers. Which configuration must the administrator perform to establish an iBGP session between routers PE1 on POP site 1 and PE2 on POP site 2?

Options

• APE2#configure terminal
• BPE1#configure terminal
• CPE1#configure terminal
• DPE2#configure terminal

Explanation

To establish an iBGP session between PEs for customer internet connectivity via MPLS L3VPN, the PE routers must be configured with an iBGP neighbor relationship using loopback interfaces, along with activating the relevant address families to exchange customer routes within their respective VRFs.

Common mistakes.

• A. This option provides a correct iBGP neighbor configuration for PE2 but lacks the configuration for the address-family specific to handling customer VRF routes, which is crucial for providing customer internet connectivity via L3VPN.
• B. This option incorrectly includes the ebgp-multihop 255 command, which is not applicable to iBGP peering and is specifically for eBGP sessions over non-directly connected interfaces.
• C. Similar to A, this option provides a correct iBGP neighbor configuration for PE1 but does not include the necessary address-family configuration for exchanging customer VRF routes.

Concept tested. iBGP PE-PE peering for L3VPN with VRF

Reference. https://www.cisco.com/c/en/us/td/docs/ios/iproute_bgp/configuration/15-mt/irg-15-mt-book/irg-mp-bgp.html

No community discussion yet for this question.