diff --git a/source/FreeRTOS_ARP.c b/source/FreeRTOS_ARP.c
index 20de92a924..cc24dbfb79 100644
--- a/source/FreeRTOS_ARP.c
+++ b/source/FreeRTOS_ARP.c
@@ -588,7 +588,7 @@ BaseType_t xCheckRequiresARPResolution( const NetworkBufferDescriptor_t * pxNetw
                                NetworkBufferDescriptor_t * pxTempBuffer;
                                size_t uxNeededSize;
 
-                               uxNeededSize = ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv6_HEADER + sizeof( ICMPRouterSolicitation_IPv6_t );
+                               uxNeededSize = sizeof( ICMPPacket_IPv6_t );
                                pxTempBuffer = pxGetNetworkBufferWithDescriptor( BUFFER_FROM_WHERE_CALL( 199 ) uxNeededSize, 0U );
 
                                if( pxTempBuffer != NULL )