No matter which protocol or combination of protocols is utilized, the transport network must be "carrier grade," that is, it must be able to guarantee maintenance of specified qual- ity levels. The QoS parameters may include data rate, one-way or round-trip delay, packet delay variation, etc. The contract between the customer (mobile operator) and the (whole- sale) service provider specifying the precise QoS parameters, their required bounds, and the consequences of not conforming to these bounds is called an SLA. When the trans- port is not provided by a distinct business entity, the parameters and their values are often called SLOs. The toolkit for monitoring QoS parameters consists of OAM protocols (see Section 6.5), which in turn are classified as FM (CC, loopbacks, etc.) and PM (packet loss measurement delay measurement, etc.). Ethernet was originally a LAN technology, and thus did not require specification of QoS parameters. When Ethernet became a service provided to business customers by metro-Ethernet service providers, it was upgraded to Carrier Ethernet by specifying QoS parameters, OAM protocols to measure them, management-based route specification, APS mechanisms (including for Ethernet rings) to rapidly recover from failures, and various other carrier grade features. MPLS was originally a mechanism to accelerate forwarding of IP packets, and thus did not require specification of QoS parameters. It has since been extended in multiple fashions, and we can now distinguish several distinct flavors: 1. Vanilla MPLS is the variety deployed in the core of the Internet to accelerate forwarding. It usually employs LDP signaling to set up label switched paths (LSPs), but is not truly connection-oriented as these LSPs change with routing updates. It may employ FRR to locally bypass faults. 2. RFC-2547 (obsoleted by RFC 4364) is the flavor used to implement Layer 3 VPN (L3VPN) services for business customers. It sets up LSPs using Border Gateway Protocol (BGP). 3. MPLS-TE is a true connection-oriented version th