diff --git a/src/client.py b/src/client.py
--- a/src/client.py
+++ b/src/client.py
@@ -4,6 +4,7 @@ import logging as log
 from datetime import datetime
 
 import config as conf
+import stats
 from util import Progress
 from hashtree import HashTree
 from networkers import NetworkReader,NetworkWriter
@@ -53,6 +54,7 @@ class Client:
 				jsonData,binData=incoming.readMsg()
 				assert jsonData["index"]==i
 				assert jsonData["dataType"]=="hash"
+				stats.logExchangedNode()
 
 				if localTree.store[i]!=binData:
 					if 2*i+3<len(localTree.store): # inner node
@@ -82,6 +84,7 @@ class Client:
 				log.info("block #{0}: {1}...{2}".format(i2,binData[:5],binData[-5:]))
 
 				outcoming.writeMsg(jsonData,binData)
+				stats.logTransferredBlock()
 				jsonData,binData=incoming.readMsg()
 				assert jsonData["command"]=="ack" and jsonData["index"]==i2, jsonData
 				i1=i2