Layer 2.5 SoftMAC: end-system based media streaming support on home networks

The requirements of multimedia streaming challenge the QoS (quality of service) capability on home networks, where typical construction is a hybrid Ethernet and WLAN (wireless LAN). This paper proposes a novel software solution, called layer 2.5 SoftMAC, to provide QoS on home network using commercial IEEE 802.11 wireless and Ethernet hardware. SoftMAC resides between 802.11/ Ethernet MAC layer and IP layer to coordinate the real-time (RT) and best-effort (BE) packets transmission among end-devices in home networks, i.e., no modification to wireless AP (access point) or Ethernet switch. To effectively support media streaming, it employs three key components: 1) admission control (AC) for regulating the load of RT traffic, 2) rate control (RC) that minimizes the impact of BE traffic on RT traffic, and 3) non-preemptive priority queueing (PQ) to provide high priority service to RT traffic. To evaluate the efficacy of SoftMAC, we conduct extensive simulations using the network simulator NS2. We also implement our proposed SoftMAC as a Windows network driver interface specification (NDIS) driver over network interface card (NIC) driver, and build a testbed to emulate hybrid home environment with 802.11 a/g and 100M Ethernet to test its performance on real system. Our evaluation and testing results demonstrate the effectiveness of SoftMAC.