1. A method for managing a service transported over a transport network between an ingress service termination point, where traffic of the service enters the transport network from a client network, and an egress service termination point, where the traffic of the service exits the transport network, the method comprising: receiving customer traffic at the ingress service termination point from the client network, the customer traffic belonging to a specific service and having a guarantee of transport from a service provider with one or more specific performance commitments; associating the customer traffic belonging to the specific service with a service identifier; measuring performance of the customer traffic belonging to the specific service at the ingress service termination point to produce an ingress performance of service (POS) service metric; measuring performance of the customer traffic belonging to the specific service at the egress service termination point to produce an egress POS service metric for the specific service, the egress POS service metric being different from the ingress POS service metric; and periodically exchanging the ingress and egress POS service metrics between the ingress service termination point and the egress service termination point.