How to Ping Remotely Connected CE Router in Layer 3 VPN

B

The correct answer to this question is option B - ping routing-instance VPN-C 122.161.2.1.

Explanation:

In a Layer 3 VPN, a provider edge (PE) router is connected to one or more customer edge (CE) routers. Each CE router is assigned one or more VPN routing instances, which are isolated from each other and communicate through the provider network. To ping the remotely connected CE router's loopback address from a PE router participating in the VPN, we need to specify the routing instance name along with the ping command.

The ping command is used to test connectivity to a remote IP address. In a Layer 3 VPN, we can use the ping command to test connectivity between the PE and CE routers across the VPN. However, we need to specify the routing instance name to ensure that the ping traffic is routed correctly through the VPN.

Option A - ping instance VPN-C 122.161.2.1 is incorrect because the correct command to specify a VPN routing instance is ping routing-instance and not ping instance.

Option C - ping VPN-C 122.161.2.1 is incorrect because it does not specify the routing instance name. The ping command without the routing instance name will use the default routing table, which may not have the correct routes to reach the remote CE router's loopback address.

Option D - ping vpn-instance VPN-C 122.161.2.1 is incorrect because the correct command to specify a VPN routing instance is ping routing-instance and not ping vpn-instance.

Therefore, the correct command to ping the remotely connected CE router's loopback address from a PE router participating in the VPN is ping routing-instance VPN-C 122.161.2.1.