{
     BOOST_ASSERT( !destination_ip.empty() );
 
-    int port = 0;
+    uint16_t port = 0;
     address destination_address = ip::address::from_string( destination_ip );
     icmp::endpoint destination_endpoint( destination_address, port );
     DestinationEndpoint = destination_endpoint;
     start_receive();
 }
 
-void BoostPinger::print_request_timeout()
+void BoostPinger::print_request_timeout() const
 {
     cout << "Request timed out" << endl;
 }
 
     size_t bytes_received = bytes_transferred - ipv4_hdr.get_header_length();
     string remote_address = ipv4_hdr.get_source_address().to_string();
-    int sequence_number = icmp_hdr.get_sequence_number();
+    uint16_t sequence_number = icmp_hdr.get_sequence_number();
     int ttl = ipv4_hdr.get_time_to_live();
     ptime now = microsec_clock::universal_time();
-    int time = (now - TimeSent).total_milliseconds();
+    int elapsed_time = (now - TimeSent).total_milliseconds();
 
     cout << bytes_received << " bytes "
          << "from " << remote_address
          << ": icmp_seq=" << sequence_number
          << " ttl=" << ttl
-         << " time=" << time << " ms" << endl;
+         << " time=" << elapsed_time << " ms" << endl;
 }
 
 void BoostPinger::print_destination_unreachable(
     IcmpHeader icmp_hdr = icmp_packet.get_icmp_header();
 
     string local_address = ipv4_hdr.get_destination_address().to_string();
-    int sequence_number = icmp_hdr.get_sequence_number();
+    uint16_t sequence_number = icmp_hdr.get_sequence_number();
 
     cout << "From " << local_address
          << " icmp_seq=" << sequence_number
 
     void start_receive();
     void handle_receive_icmp_packet( const std::size_t &bytes_transferred );
 
-    void print_request_timeout();
+    void print_request_timeout() const;
     void print_echo_reply(
             const IcmpPacket &icmp_packet,
             const std::size_t &bytes_transferred