Methods for implementing SS7 functions are proposed for a large-capacity decentralized switching node; they satisfy the condition of hiding distributed configurations from adjacent nodes. First, line accommodation and acquisition methods are clarified for a large-capacity switching node in which multiple modules are used to realize trunk circuits and SS7 signaling links. Two methods are then proposed for allocating SS7 functions within the switching node. One distributes the functions over multiple circuit-switched modules (distributed allocation) while the other centralizes the functions in dedicated signaling modules (centralized allocation). We quantitatively evaluate both methods in terms of node scale versus the number of modules and signaling links required, the inter-module data transfer rate required, and the node traffic handling capacity when a particular module fails. From the evaluation results, we show that the distributed allocation should be employed for small-scale nodes and the centralized allocation for large-scale nodes. We also show the effectiveness of a method for avoiding a characteristic problem that arises when a particular module fails. Finally, we implement an experimental system as an example.