Due to their many desirable features, delta networks are very attractive choices for interconnecting processors and memory modules in large multiprocessor systems, and for building high-speed switching fabrics for future integrated-services communication networks. Unfortunately, delta networks suffer from blocking. In this paper, a new approach for easing blocking in delta networks and improving their performance is introduced. The approach called, expansion, is applicable to both internally unbuffered and buffered delta networks. A discrete-time analytical model of the resulting expanded delta network is formulated where the presence of finite external input and output buffers with a backpressure mechanism is assumed. The performance of the expanded delta network is evaluated based on three measures; maximum throughput, delay, and packet loss probability.