Index: uspace/srv/net/tl/tl_common.c
===================================================================
--- uspace/srv/net/tl/tl_common.c	(revision 21580dd3dd9a49828a6c8dd3988e651a60708c10)
+++ uspace/srv/net/tl/tl_common.c	(revision b4ff8a6d2435311dc46c2bc8466be4feb5750e1a)
@@ -44,4 +44,5 @@
 #include "../structures/packet/packet_client.h"
 
+#include "../include/device.h"
 #include "../include/icmp_interface.h"
 #include "../include/in.h"
@@ -96,4 +97,23 @@
 			free( * packet_dimension );
 			return ERROR_CODE;
+		}
+	}
+	return EOK;
+}
+
+int tl_update_ip_packet_dimension( packet_dimensions_ref packet_dimensions, device_id_t device_id, size_t content ){
+	packet_dimension_ref	packet_dimension;
+
+	packet_dimension = packet_dimensions_find( packet_dimensions, device_id );
+	if( ! packet_dimension ) return ENOENT;
+	packet_dimension->content = content;
+	if( device_id != DEVICE_INVALID_ID ){
+		packet_dimension = packet_dimensions_find( packet_dimensions, DEVICE_INVALID_ID );
+		if( packet_dimension ){
+			if( packet_dimension->content >= content ){
+				packet_dimension->content = content;
+			}else{
+				packet_dimensions_exclude( packet_dimensions, DEVICE_INVALID_ID );
+			}
 		}
 	}
Index: uspace/srv/net/tl/tl_common.h
===================================================================
--- uspace/srv/net/tl/tl_common.h	(revision 21580dd3dd9a49828a6c8dd3988e651a60708c10)
+++ uspace/srv/net/tl/tl_common.h	(revision b4ff8a6d2435311dc46c2bc8466be4feb5750e1a)
@@ -103,4 +103,13 @@
 int	tl_get_ip_packet_dimension( int ip_phone, packet_dimensions_ref packet_dimensions, device_id_t device_id, packet_dimension_ref * packet_dimension );
 
+/** Updates IP device packet dimensions cache.
+ *  @param[in,out] packet_dimensions The packet dimensions cache.
+ *  @param[in] device_id The device identifier.
+ *  @param[in] content The new maximum content size.
+ *  @returns EOK on success.
+ *  @returns ENOENT if the packet dimension is not cached.
+ */
+int	tl_update_ip_packet_dimension( packet_dimensions_ref packet_dimensions, device_id_t device_id, size_t content );
+
 /** Sets the address port.
  *  Supports AF_INET and AF_INET6 address families.