'Configure VLANHost according to (optional) parameters:
vlan: VLAN ID for default interface'

def config(self, vlan=100, **params):

    r = super(VLANHost, self).config(**params)
    intf = self.defaultIntf()
    self.cmd(('ifconfig    %s    inet    0' % intf))
    self.cmd(('vconfig    add    %s    %d' % (intf, vlan)))
    self.cmd(('ifconfig    %s.%d    inet    %s' % (intf, vlan, params['ip'])))
    newName = ('%s.%d' % (intf, vlan))
    intf.name = newName
    self.nameToIntf[newName] = intf
    return r
