In general, techniques are described for steering data traffic for a subscriber session from a network interface of a wireless access gateway to an anchoring one of a plurality of forwarding units of the wireless access gateway using a layer 2 (L2) address of the data traffic. For example, a wireless access gateway for a wireless local area network (WLAN) access network is described as having a decentralized data plane that includes multiple forwarding units for implementing subscriber sessions. Each forwarding unit may present a network interface for sending and receiving network packets and includes packet processing capabilities to enable subscriber data packet processing to perform the functionality of the wireless access gateway. The techniques enable steering data traffic for a given subscriber session to a particular one of the forwarding units of the wireless access gateway using an L2 address of the data traffic.