Provided are node authentication and node operation methods within service and access networks for bundle authentication between the service and access networks in a next generation network (NGN). A method of authentication processing of a node (S-CSC-FE/I-CSC-FE (Serving Call Session Control Functional Entity/Interrogating Call Session Control Functional Entity)) within a service network for bundle authentication between service and access networks, the method including: receiving first authentication information about access authentication of a terminal from a first node within the service networks; requesting to receive second authentication information from a second node within the service network based on the first authentication information; and comparing the first authentication information with the second authentication information to authenticate the terminal.