diff --git a/src/wifi/model/ap-wifi-mac.cc b/src/wifi/model/ap-wifi-mac.cc
index 5ef3275f7..97a1d5fcd 100644
--- a/src/wifi/model/ap-wifi-mac.cc
+++ b/src/wifi/model/ap-wifi-mac.cc
@@ -435,6 +435,7 @@ ApWifiMac::GetCapabilities (void) const
   CapabilityInformation capabilities;
   capabilities.SetShortPreamble (GetShortPreambleEnabled ());
   capabilities.SetShortSlotTime (GetShortSlotTimeEnabled ());
+  capabilities.SetEss ();
   return capabilities;
 }
 
diff --git a/src/wifi/model/sta-wifi-mac.cc b/src/wifi/model/sta-wifi-mac.cc
index b4a09f6c9..1b065e2bf 100644
--- a/src/wifi/model/sta-wifi-mac.cc
+++ b/src/wifi/model/sta-wifi-mac.cc
@@ -456,6 +456,7 @@ StaWifiMac::Receive (Ptr<Packet> packet, const WifiMacHeader *hdr)
       MgtBeaconHeader beacon;
       packet->RemoveHeader (beacon);
       CapabilityInformation capabilities = beacon.GetCapabilities ();
+      NS_ASSERT (capabilities.IsEss ());
       bool goodBeacon = false;
       if (GetSsid ().IsBroadcast ()
           || beacon.GetSsid ().IsEqual (GetSsid ()))