--- src/comp/c_generic.c	2010-08-22 14:00:49 +0000
+++ src/comp/c_generic.c	2011-05-11 15:43:40 +0000
@@ -5937,8 +5939,8 @@
 		{
 			uint16_t id;
 
-			/* always transmit IP-ID in Network Byte Order */
-			id = ipv4_get_id_nbo(ip, g_context->ip_flags.info.v4.nbo);
+			/* IP-ID is compressed, even 16bit sent, see RFC 4815 8.2 */
+			id = htons((uint16_t)(g_context->ip_flags.info.v4.id_delta & 0xffff));
 			memcpy(&dest[counter], &id, 2);
 			rohc_debugf(3, "IP ID = 0x%02x 0x%02x\n",
 			            dest[counter], dest[counter + 1]);
@@ -6014,8 +6016,8 @@
 		{
 			uint16_t id;
 
-			/* always transmit IP-ID in Network Byte Order */
-			id = ipv4_get_id_nbo(ip2, g_context->ip2_flags.info.v4.nbo);
+			/* IP-ID is compressed, even 16bit sent, see RFC 4815 8.2 */
+			id = htons((uint16_t)(g_context->ip_flags.info.v4.id_delta & 0xffff));
 			memcpy(&dest[counter], &id, 2);
 			rohc_debugf(3, "IP ID = 0x%02x 0x%02x\n",
 			            dest[counter], dest[counter + 1]);

--- src/decomp/d_generic.c	2010-08-22 17:16:24 +0000
+++ src/decomp/d_generic.c	2011-05-11 11:33:21 +0000
@@ -5100,7 +5113,13 @@
 
 		if(g_context->multiple_ip)
 		{
-			ipv4_set_id(&active2->ip, GET_NEXT_16_BITS(packet));
+			uint16_t id;
+			
+			id = GET_NEXT_16_BITS(packet);
+			id = ntohs(id);
+			id = d_ip_id_decode(&g_context->ip_id2, id, 16, *sn);
+			id = htons(id);
+			ipv4_set_id(&active2->ip, id);
 			rohc_debugf(3, "inner IP-ID changed (0x%04x)\n",
 			            ntohs(ipv4_get_id(&active2->ip)));
 			packet += 2;
@@ -5110,7 +5129,13 @@
 		}
 		else
 		{
-			ipv4_set_id(&active1->ip, GET_NEXT_16_BITS(packet));
+			uint16_t id;
+
+			id = GET_NEXT_16_BITS(packet);
+			id = ntohs(id);
+			id = d_ip_id_decode(&g_context->ip_id1, id, 16, *sn);
+			id = htons(id);
+			ipv4_set_id(&active1->ip, id);
 			rohc_debugf(3, "outer IP-ID changed (0x%04x)\n",
 			            ntohs(ipv4_get_id(&active1->ip)));
 			packet += 2;