--- a/src/internet/helper/ipv4-address-helper.cc	Sun Nov 24 23:48:49 2013 +0100
+++ b/src/internet/helper/ipv4-address-helper.cc	Wed Nov 20 20:15:02 2013 +0100
@@ -161,7 +161,7 @@
   return retval;
 }
 
-const uint32_t N_BITS = 32;
+const uint32_t N_BITS = 32; //!< number of bits in a IPv4 address
 
 uint32_t
 Ipv4AddressHelper::NumAddressBits (uint32_t maskbits) const