It is possible to find downloadable forms that you can use as a starting point for your agreement with a 3pl service. Define the period of engagement; Logistics vendor service level agreement. Web this article discusses 11 indicators to keep the services offered with your 3pl as high as possible, which in turn will provide cost savings while servicing the customer at the. Web in logistics, a service level agreement is a contract between a business and a logistics partner that outlines the services to be provided and the performance level.