The increasing computing and storage capacity at the wireless access nodes (eNodeB and Access Points) creates opportunities for content caching at the wireless edge and, therefore, further reduction of content delivery delay. However, realizing a large-scale content caching at the wireless edge entails significant challenges, due to the difficulties of managing the vast amount of cached content and handling redirections among the large number of nodes. In this respect, we propose collaborative content caching at wireless edge nodes by coupling a low-false-positive hash table to index the cached content with centralized content routing and redirection, leveraging on software-defined networking (SDN) principles. We present emulation results to assess the benefits of the proposed solution.