def __init__(self, cwmin=None, cwmax=None, retrylimit=None, \
usecsma=False, **kwargs):
"""Constructor.
:param cwmin: Minimum contention window size.
:param cwmax: Maximum contention window size.
:param retrylimit: Maximum number of retries allowed.
:param usecsma: Boolean flag; if true, use CSMA/CA without RTS-CTS
reservation messages.
:param kwargs: Additional keywords passed to `configure()`.
The default parameters are specified by the class.
"""
if cwmin is None: cwmin = self.__class__.cwmin
if cwmax is None: cwmax = self.__class__.cwmax
if retrylimit is None: retrylimit = self.__class__.retrylimit
# timing parameters
self.sifs, self.slottime = None, None
self.cwmin, self.cwmax = cwmin, cwmax
self.cslot = None
# events and other members
self.datatosend = None
self.retrycount = None
self.retrylimit = retrylimit
self.usecsma = usecsma
self.rxdata = SimEvent(name=".rxdata")
self._ctsduration = None
self._ackduration = None
# call CSMAC constructor
CSMAC.__init__(self, **kwargs)
self.rxdata.name = "%s.rxdata"%(self.name)
