diff --git a/src/ims/in-memory-storage-fifo.hpp b/src/ims/in-memory-storage-fifo.hpp
index 6991451..bbef50a 100644
--- a/src/ims/in-memory-storage-fifo.hpp
+++ b/src/ims/in-memory-storage-fifo.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2017 Regents of the University of California.
+ * Copyright (c) 2013-2018 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -36,10 +36,10 @@
 {
 public:
   explicit
-  InMemoryStorageFifo(size_t limit = 10);
+  InMemoryStorageFifo(size_t limit = 16);
 
   explicit
-  InMemoryStorageFifo(boost::asio::io_service& ioService, size_t limit = 10);
+  InMemoryStorageFifo(boost::asio::io_service& ioService, size_t limit = 16);
 
 NDN_CXX_PUBLIC_WITH_TESTS_ELSE_PROTECTED:
   /** @brief Removes one Data packet from in-memory storage based on FIFO
diff --git a/src/ims/in-memory-storage-lfu.hpp b/src/ims/in-memory-storage-lfu.hpp
index 7633cfd..3b0531c 100644
--- a/src/ims/in-memory-storage-lfu.hpp
+++ b/src/ims/in-memory-storage-lfu.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2017 Regents of the University of California.
+ * Copyright (c) 2013-2018 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -40,10 +40,10 @@
 {
 public:
   explicit
-  InMemoryStorageLfu(size_t limit = 10);
+  InMemoryStorageLfu(size_t limit = 16);
 
   explicit
-  InMemoryStorageLfu(boost::asio::io_service& ioService, size_t limit = 10);
+  InMemoryStorageLfu(boost::asio::io_service& ioService, size_t limit = 16);
 
 NDN_CXX_PUBLIC_WITH_TESTS_ELSE_PROTECTED:
   /** @brief Removes one Data packet from in-memory storage based on LFU, i.e. evict the least
diff --git a/src/ims/in-memory-storage-lru.hpp b/src/ims/in-memory-storage-lru.hpp
index 3dd9dfe..1f15648 100644
--- a/src/ims/in-memory-storage-lru.hpp
+++ b/src/ims/in-memory-storage-lru.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2017 Regents of the University of California.
+ * Copyright (c) 2013-2018 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -38,9 +38,10 @@
 {
 public:
   explicit
-  InMemoryStorageLru(size_t limit = 10);
+  InMemoryStorageLru(size_t limit = 16);
 
-  InMemoryStorageLru(boost::asio::io_service& ioService, size_t limit = 10);
+  explicit
+  InMemoryStorageLru(boost::asio::io_service& ioService, size_t limit = 16);
 
 NDN_CXX_PUBLIC_WITH_TESTS_ELSE_PROTECTED:
   /** @brief Removes one Data packet from in-memory storage based on LRU, i.e. evict the least
diff --git a/src/ims/in-memory-storage.cpp b/src/ims/in-memory-storage.cpp
index 3db250d..cf5ca2d 100644
--- a/src/ims/in-memory-storage.cpp
+++ b/src/ims/in-memory-storage.cpp
@@ -100,7 +100,7 @@
 InMemoryStorage::init()
 {
   // TODO consider a more suitable initial value
-  m_capacity = 10;
+  m_capacity = m_initCapacity;
 
   if (m_limit != std::numeric_limits<size_t>::max() && m_capacity > m_limit) {
     m_capacity = m_limit;
@@ -131,7 +131,7 @@
 InMemoryStorage::setCapacity(size_t capacity)
 {
   size_t oldCapacity = m_capacity;
-  m_capacity = capacity;
+  m_capacity = std::max(capacity, m_initCapacity);
 
   if (size() > m_capacity) {
     ssize_t nAllowedFailures = size() - m_capacity;
diff --git a/src/ims/in-memory-storage.hpp b/src/ims/in-memory-storage.hpp
index 740b706..a962de2 100644
--- a/src/ims/in-memory-storage.hpp
+++ b/src/ims/in-memory-storage.hpp
@@ -332,6 +332,8 @@
   Cache m_cache;
   /// user defined maximum capacity of the in-memory storage in packets
   size_t m_limit;
+  /// initial capacity, used as minimum capacity
+  const size_t m_initCapacity = 16;
   /// current capacity of the in-memory storage in packets
   size_t m_capacity;
   /// current number of packets in in-memory storage