zigbee: In NWK BTT record initiator bcst to filter rebroadcasts

Author: GallegosAlberto

RELEASE_NOTES.md

@@ -44,6 +44,7 @@ been tested on Linux. As of this release, the latest known version to work with
 - (mesh) #1341 Fixed dot11s regression that ignored the link rate, degrading the HWMP routing metric to hop count.
 - (sixlowpan) #1342 Fixed a deserialization error in the MESH header.
 - (dsr) !2762 Fixes header format to comply with RFC4728. Also other minor bug fixes and modernization.
+- (zigbee) In the NWK, broadcast initiator devices are now registered in the BTT to avoid receiving retransmissions.
 
 ## Release 3.48
 

src/zigbee/model/zigbee-nwk.cc

@@ -2360,6 +2360,15 @@ ZigbeeNwk::NldeDataRequest(NldeDataRequestParams params, Ptr<Packet> packet)
         if (IsBroadcastAddress(params.m_dstAddr))
         {
             // The destination is BROADCAST (See 3.6.5)
+            // Record the originated broadcast in the Broadcast Transaction Table (BTT)
+            // so that copies rebroadcast back by neighbors are suppressed and not
+            // delivered again to the next higher layer.
+            Ptr<BroadcastTransactionRecord> btr = Create<BroadcastTransactionRecord>(
+                nwkHeader.GetSrcAddr(),
+                nwkHeader.GetSeqNum(),
+                Simulator::Now() + m_nwkNetworkBroadcastDeliveryTime);
+            m_btt.AddEntry(btr);
+
             SendDataBcst(packet, params.m_nsduHandle);
         }
         else