diff --git a/netconf/constants.py b/netconf/constants.py
index e59a73e..332ec16 100644
--- a/netconf/constants.py
+++ b/netconf/constants.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 #
-# Copyright 2016 the original author or authors.
+# Copyright 2017 the original author or authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -19,6 +19,9 @@
 
 	SSH_SUBSYSTEM = "netconf"
 
+	# Send message max size
+	MAXSSHBUF = 1024 * 1024
+
 	# Secure credentials directories
 	# TODO:  In a production environment these locations require better
 	# protection.  For now the user_passwords file is just a plain text file.
@@ -80,6 +83,8 @@
 
 	#tags
 	NC = "nc"
+	VOLTHA = 'voltha'
+	NCM = "ncm"
 	RPC = "rpc"
 	RPC_REPLY = "rpc-reply"
 	RPC_ERROR = "rpc-error"
@@ -96,3 +101,11 @@
 	MESSAGE_ID = "message-id"
 	XMLNS = "xmlns"
 	DELIMITER = "]]>]]>"
+
+	NS_MAP = {
+		'nc': 'urn:ietf:params:xml:ns:netconf:base:1.0',
+		'voltha': 'urn:opencord:params:xml:ns:voltha:ietf-voltha',
+		'ncm': 'urn:ietf:params:xml:ns:yang:ietf-netconf-monitoring'
+	}
+
+