An embodiment provides a method for implementing a service level agreement (SLA) in a network. The method includes: (1) providing one or more network devices in communication with a Network Credit Server (NCS), the NCS configured to: store a SLA of a customer, and maintain a database of topology information of the network; (2) receiving, at one of the network devices, a first plurality of packets associated with the customer and en-route to a destination; (3) transmitting, from the network device to the NCS, a request for credit when the first plurality of packets is more than a pre-configured threshold number; (4) thereafter receiving a second plurality of packets associated with the customer and en-route to the destination; and (5) forwarding, by the network device and depending on a status of a reply from the NCS, the second plurality of packets.