You provisioned a Cloud Interconnect VLAN attachment and configured BGP, but the BGP session with your on-prem router is not establishing. Which two actions should you take? (Choose two.)

When a BGP session fails to establish over Cloud Interconnect, troubleshooting often involves checking basic connectivity and configuration. The gcloud compute routers get-status command is crucial because it provides detailed information about the Cloud Router's state, including learned ARP entries. If the Cloud Router isn't learning the MAC address of the on-premises router, it indicates a Layer 2 connectivity issue, preventing BGP from forming. Additionally, for Cloud Interconnect VLAN attachments, the BGP peering links are point-to-point. Google Cloud recommends and often requires a /31 subnet mask for these links to optimize IP address usage and simplify routing, as specified in their documentation. An incorrect subnet mask on the on-premises router's subinterface will prevent the BGP session from establishing. eBGP multihop is not typically required for direct Cloud Interconnect BGP sessions, as they are usually single-hop. MD5 authentication is optional and not a prerequisite for BGP session establishment; its absence would not prevent the session from forming, only make it less secure. gcloud compute interconnects get-diagnostics provides information about the physical interconnect, not the BGP session or ARP entries learned by the Cloud Router.