diff --git a/src/include/netif/ppp/ppp.h b/src/include/netif/ppp/ppp.h
index b5bb8836..7d9ef2bd 100644
--- a/src/include/netif/ppp/ppp.h
+++ b/src/include/netif/ppp/ppp.h
@@ -347,8 +347,6 @@ struct ppp_pcb_s {
   unsigned int lcp_echo_timer_running  :1; /* set if a timer is running */
   unsigned int                         :2; /* 2 bits of padding to round out to 8 bits */
 
-  u32_t last_xmit;               /* Time of last transmission. */
-
   /* auth data */
 #if PPP_SERVER
   char peer_authname[MAXNAMELEN + 1]; /* The name by which the peer authenticated itself to us. */
diff --git a/src/include/netif/ppp/pppos.h b/src/include/netif/ppp/pppos.h
index cfb43801..cddb5437 100644
--- a/src/include/netif/ppp/pppos.h
+++ b/src/include/netif/ppp/pppos.h
@@ -71,9 +71,10 @@ struct pppos_pcb_s {
 
   /* -- below are data that will be cleared between two sessions
    *
-   * out_accm must be the first member of cleared members, because it is
+   * last_xmit must be the first member of cleared members, because it is
    * used to know which part must not be cleared.
    */
+  u32_t last_xmit;                 /* Time of last transmission. */
   ext_accm out_accm;               /* Async-Ctl-Char-Map for output. */
 
   /* flags */
diff --git a/src/netif/ppp/pppoe.c b/src/netif/ppp/pppoe.c
index f601b9d0..4e000791 100644
--- a/src/netif/ppp/pppoe.c
+++ b/src/netif/ppp/pppoe.c
@@ -232,8 +232,6 @@ static err_t pppoe_write(ppp_pcb *ppp, void *ctx, struct pbuf *p) {
   tot_len = ph->tot_len;
 #endif /* LWIP_SNMP */
 
-  ppp->last_xmit = sys_jiffies();
-
   ret = pppoe_xmit(sc, ph);
   if (ret != ERR_OK) {
     LINK_STATS_INC(link.err);
@@ -268,8 +266,6 @@ static err_t pppoe_netif_output(ppp_pcb *ppp, void *ctx, struct pbuf *p, u_short
 
   pbuf_header(pb, -(s16_t)PPPOE_HEADERLEN);
 
-  ppp->last_xmit = sys_jiffies();
-
   pl = (u8_t*)pb->payload;
   PUTSHORT(protocol, pl);
 
diff --git a/src/netif/ppp/pppol2tp.c b/src/netif/ppp/pppol2tp.c
index 8e37bc48..bff272eb 100644
--- a/src/netif/ppp/pppol2tp.c
+++ b/src/netif/ppp/pppol2tp.c
@@ -234,8 +234,6 @@ static err_t pppol2tp_write(ppp_pcb *ppp, void *ctx, struct pbuf *p) {
   tot_len = ph->tot_len;
 #endif /* LWIP_SNMP */
 
-  ppp->last_xmit = sys_jiffies();
-
   ret = pppol2tp_xmit(l2tp, ph);
   if (ret != ERR_OK) {
     LINK_STATS_INC(link.err);
@@ -270,8 +268,6 @@ static err_t pppol2tp_netif_output(ppp_pcb *ppp, void *ctx, struct pbuf *p, u_sh
 
   pbuf_header(pb, -(s16_t)PPPOL2TP_OUTPUT_DATA_HEADER_LEN);
 
-  ppp->last_xmit = sys_jiffies();
-
   pl = (u8_t*)pb->payload;
   PUTSHORT(protocol, pl);
 
diff --git a/src/netif/ppp/pppos.c b/src/netif/ppp/pppos.c
index 19dee39f..8ba90d7b 100644
--- a/src/netif/ppp/pppos.c
+++ b/src/netif/ppp/pppos.c
@@ -238,7 +238,7 @@ pppos_write(ppp_pcb *ppp, void *ctx, struct pbuf *p)
   /* If the link has been idle, we'll send a fresh flag character to
    * flush any noise. */
   err = ERR_OK;
-  if ((sys_jiffies() - ppp->last_xmit) >= PPP_MAXIDLEFLAG) {
+  if ((sys_jiffies() - pppos->last_xmit) >= PPP_MAXIDLEFLAG) {
     err = pppos_output_append(pppos, err,  nb, PPP_FLAG, 0);
   }
 
@@ -321,7 +321,7 @@ pppos_netif_output(ppp_pcb *ppp, void *ctx, struct pbuf *pb, u_short protocol)
   /* If the link has been idle, we'll send a fresh flag character to
    * flush any noise. */
   err = ERR_OK;
-  if ((sys_jiffies() - ppp->last_xmit) >= PPP_MAXIDLEFLAG) {
+  if ((sys_jiffies() - pppos->last_xmit) >= PPP_MAXIDLEFLAG) {
     err = pppos_output_append(pppos, err,  nb, PPP_FLAG, 0);
   }
 
@@ -384,7 +384,7 @@ pppos_connect(ppp_pcb *ppp, void *ctx)
 
   ppp_clear(ppp);
   /* reset PPPoS control block to its initial state */
-  memset(&pppos->out_accm, 0, sizeof(pppos_pcb) - ( (char*)&((pppos_pcb*)0)->out_accm - (char*)0 ) );
+  memset(&pppos->last_xmit, 0, sizeof(pppos_pcb) - ( (char*)&((pppos_pcb*)0)->last_xmit - (char*)0 ) );
 
 #if PPP_IPV4_SUPPORT && VJ_SUPPORT
   vj_compress_init(&pppos->vj_comp);
@@ -974,7 +974,7 @@ pppos_output_last(pppos_pcb *pppos, err_t err, struct pbuf *nb)
     }
   }
 
-  ppp->last_xmit = sys_jiffies();
+  pppos->last_xmit = sys_jiffies();
   snmp_add_ifoutoctets(ppp->netif, nb->tot_len);
   snmp_inc_ifoutucastpkts(ppp->netif);
   LINK_STATS_INC(link.xmit);
@@ -982,7 +982,7 @@ pppos_output_last(pppos_pcb *pppos, err_t err, struct pbuf *nb)
   return ERR_OK;
 
 failed:
-  ppp->last_xmit = 0; /* prepend PPP_FLAG to next packet */
+  pppos->last_xmit = 0; /* prepend PPP_FLAG to next packet */
   LINK_STATS_INC(link.err);
   LINK_STATS_INC(link.drop);
   snmp_inc_ifoutdiscards(ppp->netif);