l entities, handover function, which controls overall handover decision and signaling procedures related to handover, and context function, which performs the exchanges required in order to set-up any state or retrieve any state in network elements. Each of these functions is viewed as a peer-to-peer inter- action corresponding to the function. The DPF manages data-plane establishment between the two peers. This includes set-up of any tunnels and/or additional functionality that may be required for handling the bearer-plane. The DPF is used to set-up the bearer-plane between base stations, other entities such as gateways, or between gateways and base stations. Any additional requirements such as support of multicast or broadcast can be also handled by this function. The DPF further supports the use of packet sequence number. Each DPF is responsible for instantiating and managing bearer path with another DPF, and for selecting the payload traversing the established bearer path. There are two types of data path functions: 1. DPF Type 1 is used for IP or Ethernet packet forwarding with Layer 2 or Layer 3 transport. For DPF Type 1, the IP or Ethernet packets are forwarded using Layer 2 bridging (e.g., Ethernet protocols) or Layer 3 routing (e.g., GRE or IP-in-IP protocols) between two DPFs. Additional semantics can be applied to the transport header and payload to handle scenarios such as header compression and sequenced delivery. 2.6 Mobility management 2. DPF Type 2 is a forwarding scheme with Layer 2 or Layer 3 transport. For DPF Type 2, data path bearer is also typically a generic Layer 3 tunneling protocol such as IP-in-IP or GRE, or a Layer 2 bridging protocol such as Ethernet. The payload is a Layer 2 data packet which is defined as an IEEE 802.16-2009 MAC Service Data Unit (MSDU) or part of it appended with additional information such as Connection Identifier (CID) of the target BS, Automatic Repeat reQuest (ARQ) parameters, etc. In DPF Type 2, Layer 2 session state (e.g., ARQ state) is anchored in the Anchor