catchunks: Change the default pipeline to AIMD

The fixed pipeline needs manual tuning, and by default cannot fully
utilize the given link capacity.

refs: #4402

Change-Id: I9aec7aa8d3dda0abf6a8ae4742919849f15c1e63

tools/chunks/README.md

@@ -37,7 +37,7 @@ The default discovery method is `iterative`.
   [A Practical Congestion Control Scheme for Named Data
   Networking](https://www.researchgate.net/publication/306259672_A_Practical_Congestion_Control_Scheme_for_Named_Data_Networking)
 
-The default Interest pipeline type is `fixed`.
+The default Interest pipeline type is `aimd`.
 
 ## Usage examples
 

tools/chunks/catchunks/ndncatchunks.cpp

@@ -51,7 +51,7 @@ main(int argc, char** argv)
   std::string programName(argv[0]);
   Options options;
   std::string discoverType("iterative");
-  std::string pipelineType("fixed");
+  std::string pipelineType("aimd");
   size_t maxPipelineSize(1);
   int maxRetriesAfterVersionFound(0);
   int64_t discoveryTimeoutMs(300);