Fig. 1

SDN network data request model. As shown in Fig. 1, the optimization goal of SDN network data request model is to place the request into an idle network, making the total length of request that have been put into the idle network always the longest. The coupling relationship between requests depends on the specific coupling relationship. The network status can be simplified as (T ₁ , T ₂ , …, T _m ), where T _i is the idle duration of the ith segment. In fact, you can add an extra idle duration of the (m + 1)th segment T _m + 1 , but we can omit T _m + 1 due to the last idle time T _m + 1 is infinitely long, considering putting the request in the idle network as front as possible in the sequence. The set of network requests is reduced to (t ₁ , t ₂ , …, t _n ) and t _i is the time occupied by the ith request. In Fig. 1, the total length of idle network for the first group of networks is 19 and the total length of the request is 19, so the requests are all placed in the idle network. However, the idle network cannot all be filled in other situations that will be discussed later