1. A system comprising one or more computing devices implementing an integrated end-to-end framework for network service assurance, the system comprising: one or more processors; and memory, the memory storing computer-executable instructions for causing the system to implement the framework comprising: a presentation layer; a service management layer; a network-infrastructure management layer; and a unified network-access layer, the unified network-access layer configured  to: receive a network request in a standard abstracted format, the network request associated with at least one network element of a plurality of network elements; based on information about the at least one network element, select a vendor adaptor from a plurality of vendor adaptors; using the vendor adaptor, generate a vendor-formatted network request based at least on the received network request; and send the vendor-formatted network request to the at least one network element.