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Fixed MBCA

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This commit is contained in:
Kirill Andreev
2009-06-16 18:20:34 +04:00
parent 78d6c249ba
commit e6ac62ac02
3 changed files with 42 additions and 67 deletions
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9
src/devices/mesh/dot11s/peer-link.cc
View File

@@ -285,7 +285,7 @@ PeerLink::StateMachine (PeerEvent event,PmpReasonCode reasoncode)
case CNCL:
case CLS_ACPT:
m_state = IDLE;
// TODO Callback MLME-SignalPeerLinkStatus
m_linkStatusCallback (m_interface, m_peerAddress, m_peerMeshPointAddress, false);
break;
case REQ_RJCT:
SendPeerLinkClose (reasoncode);
@@ -366,7 +366,6 @@ PeerLink::StateMachine (PeerEvent event,PmpReasonCode reasoncode)
SendPeerLinkConfirm ();
NS_ASSERT(m_peerMeshPointAddress != Mac48Address::GetBroadcast ());
m_linkStatusCallback (m_interface, m_peerAddress, m_peerMeshPointAddress, true);
// TODO Callback MLME-SignalPeerLinkStatus
break;
case CLS_ACPT:
m_state = HOLDING;
@@ -411,7 +410,6 @@ PeerLink::StateMachine (PeerEvent event,PmpReasonCode reasoncode)
ClearRetryTimer ();
NS_ASSERT(m_peerMeshPointAddress != Mac48Address::GetBroadcast ());
m_linkStatusCallback (m_interface, m_peerAddress, m_peerMeshPointAddress, true);
// TODO Callback MLME-SignalPeerLinkStatus
break;
case CLS_ACPT:
m_state = HOLDING;
@@ -454,7 +452,6 @@ PeerLink::StateMachine (PeerEvent event,PmpReasonCode reasoncode)
m_state = HOLDING;
SendPeerLinkClose (REASON11S_MESH_CLOSE_RCVD);
SetHoldingTimer ();
m_linkStatusCallback (m_interface, m_peerAddress, m_peerMeshPointAddress, false);
break;
case OPN_RJCT:
case CNF_RJCT:
@@ -462,13 +459,11 @@ PeerLink::StateMachine (PeerEvent event,PmpReasonCode reasoncode)
ClearRetryTimer ();
SendPeerLinkClose (reasoncode);
SetHoldingTimer ();
m_linkStatusCallback (m_interface, m_peerAddress, m_peerMeshPointAddress, false);
break;
case CNCL:
m_state = HOLDING;
SendPeerLinkClose (REASON11S_PEERING_CANCELLED);
SetHoldingTimer ();
m_linkStatusCallback (m_interface, m_peerAddress, m_peerMeshPointAddress, false);
break;
default:
//11B.5.3.8 of 802.11s Draft D3.0
@@ -483,7 +478,7 @@ PeerLink::StateMachine (PeerEvent event,PmpReasonCode reasoncode)
ClearHoldingTimer ();
case TOH:
m_state = IDLE;
// TODO Callback MLME-SignalPeerLinkStatus
m_linkStatusCallback (m_interface, m_peerAddress, m_peerMeshPointAddress, false);
break;
case OPN_ACPT:
case CNF_ACPT:

93
src/devices/mesh/dot11s/peer-management-protocol.cc
View File

@@ -203,12 +203,12 @@ PeerManagementProtocol::UpdatePeerBeaconTiming(
peerLink->SetBeaconInformation (receivingTime, beaconInterval);
}
else
{
peerLink = InitiateLink (interface, peerAddress, Mac48Address::GetBroadcast (), receivingTime, beaconInterval);
peerLink->SetBeaconTimingElement (timingElement);
if (ShouldSendOpen (interface, peerAddress))
{
peerLink = InitiateLink (interface, peerAddress, Mac48Address::GetBroadcast (), receivingTime, beaconInterval);
peerLink->SetBeaconTimingElement (timingElement);
peerLink->MLMEActivePeerLinkOpen ();
}
}
}
void
@@ -281,7 +281,7 @@ PeerManagementProtocol::InitiateLink (
//find a peer link - it must not exist
if(FindPeerLink(interface, peerAddress) != 0)
{
NS_FATAL_ERROR ("Peer link must not to exist.");
NS_FATAL_ERROR ("Peer link must not exist.");
}
// Plugin must exist
PeerManagerPluginMap::iterator plugin = m_plugins.find (interface);
@@ -368,76 +368,47 @@ PeerManagementProtocol::GetNextBeaconShift (uint32_t interface)
//REMINDER:: in timing element 1) last beacon reception time is measured in units of 256 microseconds
// 2) beacon interval is mesured in units of 1024 microseconds
// 3) hereafter TU = 1024 microseconds
//Im my MAC everything is stored in MicroSeconds
uint32_t myNextTbttInTimeUnits = Simulator::Now().GetMicroSeconds();
uint32_t futureBeaconInTimeUnits = 0;
//Going through all my timing elements and detecting future beacon collisions
PeerLinksMap::iterator iface = m_peerLinks.find (interface);
NS_ASSERT (iface != m_peerLinks.end());
PeerManagerPluginMap::iterator plugin = m_plugins.find (interface);
NS_ASSERT(plugin != m_plugins.end());
NS_ASSERT (plugin != m_plugins.end());
std::pair<Time, Time> myBeacon = plugin->second->GetBeaconInfo ();
for (PeerLinksOnInterface::iterator i = iface->second.begin (); i != iface->second.end (); i++)
{
IeBeaconTiming::NeighboursTimingUnitsList neighbours;
if((*i)->LinkIsIdle ())
continue;
neighbours = (*i)->GetBeaconTimingElement ().GetNeighboursTimingElementsList();
//first let's form the list of all kown Tbtts
//Going through all my timing elements and detecting future beacon collisions
for (IeBeaconTiming::NeighboursTimingUnitsList::const_iterator j = neighbours.begin (); j != neighbours.end(); j++)
{
uint16_t beaconIntervalTimeUnits;
beaconIntervalTimeUnits = (*j)->GetBeaconInterval ();
//The last beacon time in timing elememt in Time Units
uint32_t lastBeaconInTimeUnits;
lastBeaconInTimeUnits = (*j)->GetLastBeacon ()/4;
//The time of my next beacon sending in Time Units
myNextTbttInTimeUnits = myBeacon.first.GetMicroSeconds ()/1024;
//My beacon interval in Time Units
uint32_t myBeaconIntervalInTimeUnits;
myBeaconIntervalInTimeUnits = myBeacon.second.GetMicroSeconds ()/1024;
//The time the beacon of other station will be sent
//we need the time just after my next Tbtt (or equal to my Tbtt)
futureBeaconInTimeUnits = lastBeaconInTimeUnits + beaconIntervalTimeUnits;
//We apply MBAC only if beacon Intervals are equal
if (beaconIntervalTimeUnits == myBeaconIntervalInTimeUnits)
if ((*j)->GetBeaconInterval () == TimeToTu (myBeacon.second))
{
//We know when the neighbor STA transmitted it's beacon
//Now we need to know when it's going to send it's beacon in the future
//So let's use the valuse of it's beacon interval
while (myNextTbttInTimeUnits >= futureBeaconInTimeUnits)
futureBeaconInTimeUnits = futureBeaconInTimeUnits + beaconIntervalTimeUnits;
//If we found that my Tbtt coincide with another STA's Tbtt
//break all cylce and return time shift for my next Tbtt
if (myNextTbttInTimeUnits == futureBeaconInTimeUnits)
break;
//Apply MBCA if future beacons may coinside
if ((TimeToTu (myBeacon.first) - ((*j)->GetLastBeacon ()/4)) % ((*j)->GetBeaconInterval ()) == 0)
{
UniformVariable randomSign (-1, 1);
UniformVariable randomShift (1, 15);
//So, the shift is a random integer variable uniformly distributed in [-15;-1] U [1;15]
int beaconShift = randomShift.GetInteger (1,15) * ((randomSign.GetValue () >= 0) ? 1 : -1);
NS_LOG_DEBUG ("Apply MBCA: Shift value = " << beaconShift << " beacon TUs");
//Do not shift to the past!
return (TuToTime (beaconShift) + Simulator::Now() < myBeacon.first) ? TuToTime (beaconShift) : TuToTime (0);
}
}
}
if (myNextTbttInTimeUnits == futureBeaconInTimeUnits)
break;
}
//Tbtts coincide, so let's calculate the shift
if (myNextTbttInTimeUnits == futureBeaconInTimeUnits)
{
NS_LOG_DEBUG ("MBCA: Future beacon collision is detected, applying avoidance mechanism");
UniformVariable randomSign (-1, 1);
int coefficientSign = -1;
if (randomSign.GetValue () >= 0)
coefficientSign = 1;
UniformVariable randomShift (1, 15);
//So, the shift is a random integer variable uniformly distributed in [-15;-1] U [1;15]
int beaconShift = randomShift.GetInteger (1,15) * coefficientSign;
NS_LOG_DEBUG ("Shift value = " << beaconShift << " beacon TUs");
//We need the result not in Time Units, but in microseconds
//Do not shift to the past
if(MicroSeconds(beaconShift * 1024) + Simulator::Now() < myBeacon.first)
return MicroSeconds (beaconShift * 1024);
else
return MicroSeconds (0);
}
//No collision detected, hence no shift is needed
else
return MicroSeconds (0);
}
Time
PeerManagementProtocol::TuToTime (uint32_t x)
{
return MicroSeconds (x * 1024);
}
uint32_t
PeerManagementProtocol::TimeToTu (Time x)
{
return (uint32_t) (x.GetMicroSeconds ()/1024);
}
void
PeerManagementProtocol::PeerLinkStatus (uint32_t interface, Mac48Address peerAddress, Mac48Address peerMeshPointAddress, bool status)
{
@@ -459,6 +430,8 @@ PeerManagementProtocol::PeerLinkStatus (uint32_t interface, Mac48Address peerAdd
{
m_stats.linksClosed ++;
m_numberOfActivePeers --;
Ptr <PeerLink> link = FindPeerLink (interface, peerAddress);
NS_ASSERT (link == 0);
}
if(!m_peerStatusCallback.IsNull ())
m_peerStatusCallback (peerMeshPointAddress, peerAddress, interface, status);

7
src/devices/mesh/dot11s/peer-management-protocol.h
View File

@@ -192,6 +192,13 @@ private:
void PeerLinkStatus (uint32_t interface, Mac48Address peerAddress, Mac48Address peerMeshPointAddres, bool status);
///\brief BCA
Time GetNextBeaconShift (uint32_t interface);
/**
* \name Time<-->TU converters:
* \{
*/
Time TuToTime (uint32_t x);
uint32_t TimeToTu (Time x);
///\}
private:
PeerManagerPluginMap m_plugins;
Mac48Address m_address;