diff --git a/sys/dev/rtwn/if_rtwn.c b/sys/dev/rtwn/if_rtwn.c
--- a/sys/dev/rtwn/if_rtwn.c
+++ b/sys/dev/rtwn/if_rtwn.c
@@ -268,6 +268,9 @@
 	ic->ic_flags_ext |= IEEE80211_FEXT_WATCHDOG;
 #endif
 
+	/* Enable seqno offload */
+	ic->ic_flags_ext |= IEEE80211_FEXT_SEQNO_OFFLOAD;
+
 	/* Adjust capabilities. */
 	rtwn_adj_devcaps(sc);
 
diff --git a/sys/dev/rtwn/if_rtwn_tx.c b/sys/dev/rtwn/if_rtwn_tx.c
--- a/sys/dev/rtwn/if_rtwn_tx.c
+++ b/sys/dev/rtwn/if_rtwn_tx.c
@@ -183,6 +183,10 @@
 		}
 	}
 
+	/* seqno allocate, only if AMPDU isn't running */
+	if ((m->m_flags & M_AMPDU_MPDU) == 0)
+		ieee80211_output_seqno_assign(ni, -1, m);
+
 	cipher = IEEE80211_CIPHER_NONE;
 	if (wh->i_fc[1] & IEEE80211_FC1_PROTECTED) {
 		k = ieee80211_crypto_encap(ni, m);
@@ -229,6 +233,10 @@
 	uint8_t type;
 	u_int cipher;
 
+	/* seqno allocate, only if AMPDU isn't running */
+	if ((m->m_flags & M_AMPDU_MPDU) == 0)
+		ieee80211_output_seqno_assign(ni, -1, m);
+
 	/* Encrypt the frame if need be. */
 	cipher = IEEE80211_CIPHER_NONE;
 	if (params->ibp_flags & IEEE80211_BPF_CRYPTO) {
diff --git a/sys/dev/rtwn/rtl8192c/r92c_tx.c b/sys/dev/rtwn/rtl8192c/r92c_tx.c
--- a/sys/dev/rtwn/rtl8192c/r92c_tx.c
+++ b/sys/dev/rtwn/rtl8192c/r92c_tx.c
@@ -452,11 +452,10 @@
 	} else {
 		uint16_t seqno;
 
-		if (m->m_flags & M_AMPDU_MPDU) {
-			seqno = ni->ni_txseqs[tid] % IEEE80211_SEQ_RANGE;
-			ni->ni_txseqs[tid]++;
-		} else
-			seqno = M_SEQNO_GET(m) % IEEE80211_SEQ_RANGE;
+		if (m->m_flags & M_AMPDU_MPDU)
+			ieee80211_output_seqno_assign(ni, -1, m);
+
+		seqno = M_SEQNO_GET(m);
 
 		/* Set sequence number. */
 		txd->txdseq = htole16(seqno);
@@ -511,7 +510,7 @@
 		rtwn_r92c_tx_setup_hwseq(sc, txd);
 	} else {
 		/* Set sequence number. */
-		txd->txdseq |= htole16(M_SEQNO_GET(m) % IEEE80211_SEQ_RANGE);
+		txd->txdseq |= htole16(M_SEQNO_GET(m));
 	}
 }
 
diff --git a/sys/dev/rtwn/rtl8812a/r12a_tx.c b/sys/dev/rtwn/rtl8812a/r12a_tx.c
--- a/sys/dev/rtwn/rtl8812a/r12a_tx.c
+++ b/sys/dev/rtwn/rtl8812a/r12a_tx.c
@@ -433,12 +433,9 @@
 	} else {
 		uint16_t seqno;
 
-		if (m->m_flags & M_AMPDU_MPDU) {
-			seqno = ni->ni_txseqs[tid];
-			ni->ni_txseqs[tid]++;
-		} else
-			seqno = M_SEQNO_GET(m) % IEEE80211_SEQ_RANGE;
-
+		if (m->m_flags & M_AMPDU_MPDU)
+			ieee80211_output_seqno_assign(ni, -1, m);
+		seqno = M_SEQNO_GET(m);
 		/* Set sequence number. */
 		txd->txdw9 |= htole32(SM(R12A_TXDW9_SEQ, seqno));
 	}
@@ -493,8 +490,7 @@
 		txd->txdw3 |= htole32(SM(R12A_TXDW3_SEQ_SEL, uvp->id));
 	} else {
 		/* Set sequence number. */
-		txd->txdw9 |= htole32(SM(R12A_TXDW9_SEQ,
-		    M_SEQNO_GET(m) % IEEE80211_SEQ_RANGE));
+		txd->txdw9 |= htole32(SM(R12A_TXDW9_SEQ, M_SEQNO_GET(m)));
 	}
 }