Delivery of services requires that a number of operations occur properly and at different levels in the service delivery model. For example, operations—such as the association of packets to a service, VC labels to a service, and each service to a service tunnel—must be performed properly in the forwarding plane for the service to function properly. In order to verify that a service is operational, a set of in-band, packet-based OAM tools is provided, with the ability to test each of the individual packet operations.
For in-band testing, the OAM packets closely resemble customer packets in order to effectively test the customer's forwarding path, but they are distinguishable from customer packets so that they can be kept within the service provider's network and not get forwarded to the customer.
The suite of OAM diagnostics supplements the basic IP ping and traceroute operations with diagnostics specialized for the different levels in the service delivery model. In addition, there are diagnostics for MPLS LSPs, SDPs, and Services within a service.
This section describes the following topics: