An Energy Efficient Mobility Management Mechanism in Software Defined Networking (SDN)

Software Delined Networking (SDN) has paved the way for cost effective, energy efficient, and flexible and dynamic network structure. In SDN, a controller sets routing path for the data plane consisting of several switches. If an incoming packet is not known to a switch, the switch needs to invoke the controller, in turn the controller facilitates forwarding path for that packet. In case when a station is mobile (e.g., mobile phone or laptop), the controller needs to update the SDN forwarding path whenever the Mobile Terminal (MT) gets attached with a new switch. This will result in increasing location update overhead at not only the controller but also all the intermediate switches between the main controller and Leaf Switch (LS). Some of the existing research efforts consider both SDN forwarding path update and Layer 3 location update whenever a MT attaches with a new LS. In our study, we have realized that if mobile IP over SDN is managed, a network operator will end up imposing additional location update cost. In this paper, a novel overlay SDN topology is proposed in order to manage location update of MTs. In this contribution, a MT maintains its location update with a Root Switch (RS), which is in charge of tracking location of MTs within a cluster of cells, as long as the MT stays within the cluster (regional area). However, if the MT moves out of the regional area, in our proposal, there will be a location update at the main controller. Results obtained through numerical analysis reveal that proposed overlay topology based location update mechanism in SDN can lead to reduced location update cost noticeably.