diff --git a/src/core/init.c b/src/core/init.c
index f74ff4bd..6a318313 100644
--- a/src/core/init.c
+++ b/src/core/init.c
@@ -292,10 +292,10 @@
 #if TCP_SNDQUEUELOWAT >= TCP_SND_QUEUELEN
   #error "lwip_sanity_check: WARNING: TCP_SNDQUEUELOWAT must be less than TCP_SND_QUEUELEN. If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
 #endif
-#if !MEMP_MEM_MALLOC && (PBUF_POOL_BUFSIZE <= (PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))
+#if !MEMP_MEM_MALLOC && (PBUF_POOL_BUFSIZE <= (PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))
   #error "lwip_sanity_check: WARNING: PBUF_POOL_BUFSIZE does not provide enough space for protocol headers. If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
 #endif
-#if !MEMP_MEM_MALLOC && (TCP_WND > (PBUF_POOL_SIZE * (PBUF_POOL_BUFSIZE - (PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))))
+#if !MEMP_MEM_MALLOC && (TCP_WND > (PBUF_POOL_SIZE * (PBUF_POOL_BUFSIZE - (PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))))
   #error "lwip_sanity_check: WARNING: TCP_WND is larger than space provided by PBUF_POOL_SIZE * (PBUF_POOL_BUFSIZE - protocol headers). If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
 #endif
 #if TCP_WND < TCP_MSS
diff --git a/src/core/ipv4/icmp.c b/src/core/ipv4/icmp.c
index 9b4427f6..9f876fef 100644
--- a/src/core/ipv4/icmp.c
+++ b/src/core/ipv4/icmp.c
@@ -143,7 +143,7 @@ icmp_input(struct pbuf *p, struct netif *inp)
     }
 #endif
 #if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
-    if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
+    if (pbuf_header(p, (PBUF_IP_HLEN + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN))) {
       /* p is not big enough to contain link headers
        * allocate a new one and copy p into it
        */
@@ -175,7 +175,7 @@ icmp_input(struct pbuf *p, struct netif *inp)
       p = r;
     } else {
       /* restore p->payload to point to icmp header */
-      if (pbuf_header(p, -(s16_t)(PBUF_IP_HLEN + PBUF_LINK_HLEN))) {
+      if (pbuf_header(p, -(s16_t)(PBUF_IP_HLEN + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN))) {
         LWIP_ASSERT("icmp_input: restoring original p->payload failed\n", 0);
         goto memerr;
       }
diff --git a/src/core/pbuf.c b/src/core/pbuf.c
index a00d42aa..7126eac9 100644
--- a/src/core/pbuf.c
+++ b/src/core/pbuf.c
@@ -378,15 +378,19 @@ pbuf_alloced_custom(pbuf_layer l, u16_t length, pbuf_type type, struct pbuf_cust
   switch (l) {
   case PBUF_TRANSPORT:
     /* add room for transport (often TCP) layer header */
-    offset = PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN;
+    offset = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN;
     break;
   case PBUF_IP:
     /* add room for IP layer header */
-    offset = PBUF_LINK_HLEN + PBUF_IP_HLEN;
+    offset = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN;
     break;
   case PBUF_LINK:
     /* add room for link layer header */
-    offset = PBUF_LINK_HLEN;
+    offset = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN;
+    break;
+  case PBUF_RAW_TX:
+    /* add room for encapsulating link layer headers (e.g. 802.11) */
+    offset = PBUF_LINK_ENCAPSULATION_HLEN;
     break;
   case PBUF_RAW:
     offset = 0;
diff --git a/src/core/snmp/mib2.c b/src/core/snmp/mib2.c
index 4f1c6671..e8f0d9a6 100644
--- a/src/core/snmp/mib2.c
+++ b/src/core/snmp/mib2.c
@@ -3123,7 +3123,7 @@ ip_addrentry_get_value(struct obj_def *od, u16_t len, void *value)
            * The current solution is to calculate for 2 simultaneous packets...
            */
           *sint_ptr = (IP_HLEN + ((IP_REASS_MAX_PBUFS/2) *
-            (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN - IP_HLEN)));
+            (PBUF_POOL_BUFSIZE - PBUF_LINK_ENCAPSULATION_HLEN - PBUF_LINK_HLEN - IP_HLEN)));
 #else
           /** @todo returning MTU would be a bad thing and
              returning a wild guess like '576' isn't good either */
diff --git a/src/include/lwip/opt.h b/src/include/lwip/opt.h
index fe53defd..4da16afb 100644
--- a/src/include/lwip/opt.h
+++ b/src/include/lwip/opt.h
@@ -1296,7 +1296,7 @@
  * TCP_MSS, IP header, and link header.
  */
 #ifndef PBUF_POOL_BUFSIZE
-#define PBUF_POOL_BUFSIZE               LWIP_MEM_ALIGN_SIZE(TCP_MSS+40+PBUF_LINK_HLEN)
+#define PBUF_POOL_BUFSIZE               LWIP_MEM_ALIGN_SIZE(TCP_MSS+40+PBUF_LINK_ENCAPSULATION_HLEN+PBUF_LINK_HLEN)
 #endif
 
 /*
diff --git a/src/netif/ppp/pppos.c b/src/netif/ppp/pppos.c
index 5abf472c..cf59e19d 100644
--- a/src/netif/ppp/pppos.c
+++ b/src/netif/ppp/pppos.c
@@ -569,7 +569,7 @@ pppos_input(ppp_pcb *ppp, u8_t *s, int l)
           pppos->in_tail = NULL;
 #if IP_FORWARD || LWIP_IPV6_FORWARD
           /* hide the room for Ethernet forwarding header */
-          pbuf_header(inp, -(s16_t)PBUF_LINK_HLEN);
+          pbuf_header(inp, -(s16_t)(PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN));
 #endif /* IP_FORWARD || LWIP_IPV6_FORWARD */
 #if PPP_INPROC_IRQ_SAFE
           if(tcpip_callback_with_block(pppos_input_callback, inp, 0) != ERR_OK) {
@@ -672,12 +672,12 @@ pppos_input(ppp_pcb *ppp, u8_t *s, int l)
             /* If we haven't started a packet, we need a packet header. */
             pbuf_alloc_len = 0;
 #if IP_FORWARD || LWIP_IPV6_FORWARD
-            /* If IP forwarding is enabled we are reserving PBUF_LINK_HLEN bytes so
-             * the packet is being allocated with enough header space to be
-             * forwarded (to Ethernet for example).
+            /* If IP forwarding is enabled we are reserving PBUF_LINK_ENCAPSULATION_HLEN
+             * + PBUF_LINK_HLEN bytes so the packet is being allocated with enough header
+             * space to be forwarded (to Ethernet for example).
              */
             if (pppos->in_head == NULL) {
-              pbuf_alloc_len = PBUF_LINK_HLEN;
+              pbuf_alloc_len = PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN;
             }
 #endif /* IP_FORWARD || LWIP_IPV6_FORWARD */
             next_pbuf = pbuf_alloc(PBUF_RAW, pbuf_alloc_len, PBUF_POOL);
diff --git a/src/netif/slipif.c b/src/netif/slipif.c
index 2a1277e4..f1765de7 100644
--- a/src/netif/slipif.c
+++ b/src/netif/slipif.c
@@ -252,7 +252,7 @@ slipif_rxbyte(struct netif *netif, u8_t c)
   if (priv->p == NULL) {
     /* allocate a new pbuf */
     LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
-    priv->p = pbuf_alloc(PBUF_LINK, (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN), PBUF_POOL);
+    priv->p = pbuf_alloc(PBUF_LINK, (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN - PBUF_LINK_ENCAPSULATION_HLEN), PBUF_POOL);
 
     if (priv->p == NULL) {
       LINK_STATS_INC(link.drop);
diff --git a/test/unit/tcp/test_tcp_oos.c b/test/unit/tcp/test_tcp_oos.c
index 97657f98..906a4676 100644
--- a/test/unit/tcp/test_tcp_oos.c
+++ b/test/unit/tcp/test_tcp_oos.c
@@ -643,7 +643,7 @@ END_TEST
 
 START_TEST(test_tcp_recv_ooseq_max_bytes)
 {
-#if TCP_OOSEQ_MAX_BYTES && (TCP_OOSEQ_MAX_BYTES < (TCP_WND + 1)) && (PBUF_POOL_BUFSIZE >= (TCP_MSS + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))
+#if TCP_OOSEQ_MAX_BYTES && (TCP_OOSEQ_MAX_BYTES < (TCP_WND + 1)) && (PBUF_POOL_BUFSIZE >= (TCP_MSS + PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))
   int i, k;
   struct test_tcp_counters counters;
   struct tcp_pcb* pcb;
@@ -717,14 +717,14 @@ START_TEST(test_tcp_recv_ooseq_max_bytes)
   EXPECT(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
   tcp_abort(pcb);
   EXPECT(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
-#endif /* TCP_OOSEQ_MAX_BYTES && (TCP_OOSEQ_MAX_BYTES < (TCP_WND + 1)) && (PBUF_POOL_BUFSIZE >= (TCP_MSS + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN)) */
+#endif /* TCP_OOSEQ_MAX_BYTES && (TCP_OOSEQ_MAX_BYTES < (TCP_WND + 1)) && (PBUF_POOL_BUFSIZE >= (TCP_MSS + PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN)) */
   LWIP_UNUSED_ARG(_i);
 }
 END_TEST
 
 START_TEST(test_tcp_recv_ooseq_max_pbufs)
 {
-#if TCP_OOSEQ_MAX_PBUFS && (TCP_OOSEQ_MAX_PBUFS < ((TCP_WND / TCP_MSS) + 1)) && (PBUF_POOL_BUFSIZE >= (TCP_MSS + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))
+#if TCP_OOSEQ_MAX_PBUFS && (TCP_OOSEQ_MAX_PBUFS < ((TCP_WND / TCP_MSS) + 1)) && (PBUF_POOL_BUFSIZE >= (TCP_MSS + PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))
   int i;
   struct test_tcp_counters counters;
   struct tcp_pcb* pcb;
@@ -798,7 +798,7 @@ START_TEST(test_tcp_recv_ooseq_max_pbufs)
   EXPECT(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
   tcp_abort(pcb);
   EXPECT(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
-#endif /* TCP_OOSEQ_MAX_PBUFS && (TCP_OOSEQ_MAX_BYTES < (TCP_WND + 1)) && (PBUF_POOL_BUFSIZE >= (TCP_MSS + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN)) */
+#endif /* TCP_OOSEQ_MAX_PBUFS && (TCP_OOSEQ_MAX_BYTES < (TCP_WND + 1)) && (PBUF_POOL_BUFSIZE >= (TCP_MSS + PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN)) */
   LWIP_UNUSED_ARG(_i);
 }
 END_TEST