The SWANS link layer entity receives upcalls from the radio entity and passes them to the network entity. It also receives downcalls from the network layer and passes them to the radio entity. The link layer entity is responsible for the implementation of a chosen medium access protocol and for encapsulating the network packet in a frame. Link layer implementations include IEEE 802.11b and a ``dumb'' protocol. The 802.11b implementation includes the complete DCF functionality, with retransmission, NAV and backoff functionality. It does not include the PCF (access-point), fragmentation or frequency hopping functionality found in the specification. This is on par with the GloMoSim and ns2 implementations. The ``dumb'' link entity will only transmit a signal if the radio is currently idle.
|MacInterface||MacDumb||transmits only if transceiver is idle|
|MacInfo||unique and shared mac parameters|