In an end-to end Layer 2 service, which technology provides the capability to detect, verify, isolate, and report faults across a provider network?
The technology that provides the capability to detect, verify, isolate, and report faults across a provider network in an end-to-end Layer 2 service is CFM or Connectivity Fault Management.
CFM is a protocol that is defined in IEEE 802.1ag and is used to detect faults and measure performance in Ethernet networks. It is designed to provide end-to-end fault detection and isolation capabilities for Layer 2 services. It can detect and report a wide range of faults, including link failures, excessive packet loss, and misconfigurations.
CFM works by exchanging messages between endpoints and intermediate devices, known as Maintenance End Points (MEPs) and Maintenance Intermediate Points (MIPs). These messages can be used to verify connectivity, measure performance, and detect faults. CFM also provides mechanisms for isolating faults to specific segments of the network and reporting faults to network management systems.
In contrast, BFD (Bidirectional Forwarding Detection) is a protocol used to detect faults in the forwarding path between two network devices. It is typically used to detect faults in Layer 3 routing protocols. UDLD (UniDirectional Link Detection) is a protocol used to detect unidirectional links in a network.
Carrier Detect is a physical layer signal that indicates the presence or absence of a carrier signal on a network link. It is used to detect faults in the physical layer of a network, but it does not provide end-to-end fault detection and isolation capabilities like CFM.
Therefore, CFM is the correct answer as it is designed specifically for end-to-end Layer 2 service fault detection, isolation, and reporting.