Mismatched OSPF hello and dead timers are a classic cause of intermittent adjacency flapping. Routers must agree on these timers to maintain neighbor relationships. While other options are valid checks, they are less likely to cause the specific symptom of intermittent drops with stable BFD and physical links.

The recommended and scalable practice is to use a single BGP session to the CE. Sophisticated import and export routing policies on the 7750 SR can then control the flow of routes between the internet routing table (from the service provider) and the customer’s VRF, providing full control and efficiency.

RSVP-TE Fast Reroute (FRR), specifically one-to-one backup (detour), pre-signals a backup label-switched path around a protected node or link. This backup path is established and ready before a failure, allowing for sub-50ms switchover, which fulfills the requirement for an immediately available backup.

A common reason for a SAP being operationally down is a mismatch in encapsulation. The SAP configuration defines what frames it expects (e.g., VLAN 100). If incoming frames have a different VLAN tag or are untagged, the SAP will not come up. This check is more specific than general interface or service states.

AS_PATH prepending is the standard technique to make a path less desirable. By prepending your own ASN multiple times in the AS_PATH of routes advertised to an external peer, you make the path through your network appear longer, discouraging that peer from using you to reach the networks behind the other peer.

In the BGP/MPLS IP VPN architecture, the ingress PE router performs the key function of imposing two labels on the customer packet: an inner VPN label (assigned by the egress PE and learned via MP-BGP) and an outer transport label (for the LSP to the egress PE).

Service Performance Measurement (PM) with TWAMP Light is an embedded feature in Nokia SROS that actively generates and reflects test packets to measure two-way performance metrics like latency, jitter, and packet loss between two endpoints, providing real-time service assurance.

The standard hitless upgrade procedure for an MC-LAG pair involves upgrading the standby node first. After it reboots and rejoins the MC-LAG as standby, a manual administrative switchover moves all traffic to it. The former active (now standby) node can then be upgraded safely, ensuring one node is always active and forwarding traffic.

The primary reason is stability and redundancy. A loopback interface is a virtual interface that is not tied to any physical hardware. As long as the router is reachable via any path, the loopback IP is reachable. This prevents BGP/IGP sessions from dropping due to a single link failure if an alternative path to the loopback exists.

Mismatched OSPF hello and dead timers are a classic cause of intermittent adjacency flapping. Routers must agree on these timers to maintain neighbor relationships. While other options are valid checks, they are less likely to cause the specific symptom of intermittent drops with stable BFD and physical links.0