chunks: change default version discovery to 'iterative'

refs #3771

Change-Id: I67c2589776a122b2e0d790b37e63617eccee9196
diff --git a/tools/chunks/README.md b/tools/chunks/README.md
index 3f0ffd6..3026363 100644
--- a/tools/chunks/README.md
+++ b/tools/chunks/README.md
@@ -23,8 +23,7 @@
                version number.  The version is declared "latest" after a predefined number of
                data retrieval timeouts (default: 1).
 
-The default discovery method is `fixed`. Other methods will be implemented in future versions
-of the tool.
+The default discovery method is `iterative`.
 
 
 ## Usage examples
@@ -67,7 +66,7 @@
 if the version is known to be `%FD%00%00%01Qc%CF%17v`, the following command will fetch that
 exact version of the file:
 
-    ndncatchunks ndn:/localhost/demo/gpl3/%FD%00%00%01Qc%CF%17v
+    ndncatchunks -d fixed ndn:/localhost/demo/gpl3/%FD%00%00%01Qc%CF%17v
 
 
 For more information, run the programs with `--help` as argument.
diff --git a/tools/chunks/catchunks/ndncatchunks.cpp b/tools/chunks/catchunks/ndncatchunks.cpp
index c877eaa..1f5bd0b 100644
--- a/tools/chunks/catchunks/ndncatchunks.cpp
+++ b/tools/chunks/catchunks/ndncatchunks.cpp
@@ -44,7 +44,7 @@
 {
   std::string programName(argv[0]);
   Options options;
-  std::string discoverType("fixed");
+  std::string discoverType("iterative");
   std::string pipelineType("fixed");
   size_t maxPipelineSize(1);
   int maxRetriesAfterVersionFound(1);