diff --git a/src/sync-core.cc b/src/sync-core.cc
index d0312d0..21201aa 100644
--- a/src/sync-core.cc
+++ b/src/sync-core.cc
@@ -22,7 +22,113 @@
 #include "sync-core.h"
 
 SyncCore::SyncCore
-         : m_log(path, localName)
+         : m_log(path, userName)
+         , m_localPrefix(localPrefix)
+         , m_syncPrefix(syncPrefix)
+         , m_stateMsgCallback(callback)
          , m_handle(handle)
+         , m_scheduler(scheduler)
 {
+  m_rootHash = m_log.RememberStateInStateLog();
+  m_interestClosure = new Closure(0, boost::bind(&SyncCore::handleSyncData, this, _1, _2), boost::bind(&SyncCore::handleSyncInterestTimeout, this, _1));
+  m_scheduler->start();
+  sendSyncInterest();
+}
+
+SyncCore::~SyncCore()
+{
+  m_scheduler->stop();
+  delete m_interestClosure;
+  m_interestClosure = 0;
+}
+
+void
+SyncCore::updateLocalPrefix(const Name &localPrefix)
+{
+  m_localPrefix = localPrefix;
+  // optionally, we can have a sync action to announce the new prefix
+  // we are not doing this for now
+}
+
+void
+SyncCore::updateLocalState(seqno_t seqno)
+{
+  m_log.UpdateDeviceSeqNo(seqno);
+  HashPtr oldHash = m_rootHash;
+  m_rootHash = m_log.RememberStateInStateLog();
+
+  SyncStateMsgPtr msg = m_log.FindStateDifferences(oldHash, m_rootHash);
+
+  // reply sync Interest with oldHash as last component
+  Name syncName = constructSyncName(oldHash);
+  Bytes syncData;
+  msgToBytes(msg, syncData);
+  m_handle->publishData(syncName, syncData, FRESHNESS);
+
+  // no hurry in sending out new Sync Interest; if others send the new Sync Interest first, no problem, we know the new root hash already;
+  // this is trying to avoid the situation that the order of SyncData and new Sync Interest gets reversed at receivers
+  ostringstream ss;
+  ss << m_rootHash;
+  TaskPtr task(new OneTimeTask(boost::bind(&SyncCore::sendSyncInterest, this), ss.str(), m_scheduler, 0.05));
+  m_scheduler->addTask(task);
+}
+
+void
+SyncCore::handleSyncInterest(const Name &name)
+{
+}
+
+Closure::TimeoutCallbackReturnValue
+SyncCore::handleSyncInterestTimeout(const Name &name)
+{
+  // sendInterestInterest with the current root hash;
+  sendSyncInterest();
+  return Closure::OK;
+}
+
+void
+SyncCore::handleSyncData(const Name &name, const Bytes &content)
+{
+  SyncStateMsgPtr msg(new SyncStateMsg);
+  bool success = msg->ParseFromArray(head(content), content.size());
+  if(!success)
+  {
+    // ignore misformed SyncData
+    cerr << "Misformed SyncData with name: " << name << endl;
+    return;
+  }
+
+  int size = msg->state_size();
+  int index = 0;
+  while (index < size)
+  {
+    SyncState state = msg->state(index);
+    index++;
+  }
+
+}
+
+void
+SyncCore::sendSyncInterest()
+{
+  Name syncInterest = constructSyncName(m_rootHash);
+  sendInterest(syncInterest, m_interestClosure);
+}
+
+Name
+SyncCore::constructSyncName(const HashPtr &hash)
+{
+  Bytes bytes;
+  readRaw(bytes, (const unsigned char*)hash->GetHash(), hash->GetHashBytes);
+  Name syncName = m_syncPrefix;
+  syncName.append(bytes);
+  return syncName;
+}
+
+void
+SyncCore::msgToBytes(const SyncStateMsgPtr &msg, Bytes &bytes)
+{
+  int size = msg.ByteSize();
+  bytes.resize(size);
+  msg.SerializeToArray(head(bytes), size);
 }