diff --git a/src/main/java/net/floodlightcontroller/bgproute/Ptree.java b/src/main/java/net/floodlightcontroller/bgproute/Ptree.java
new file mode 100644
index 0000000..d53789e
--- /dev/null
+++ b/src/main/java/net/floodlightcontroller/bgproute/Ptree.java
@@ -0,0 +1,316 @@
+package net.floodlightcontroller.bgproute;
+
+public class Ptree {
+	int maxKeyBits;
+	int maxKeyOctets;
+	int refCount;
+	PtreeNode top;
+	byte maskBits[] = { (byte)0x00, (byte)0x80, (byte)0xc0, (byte)0xe0, (byte)0xf0, (byte)0xf8, (byte)0xfc, (byte)0xfe, (byte)0xff };
+	
+	// Constructor.
+	Ptree(int max_key_bits) {
+		maxKeyBits = max_key_bits;
+		maxKeyOctets = bit_to_octet(max_key_bits); 
+		refCount = 0;
+	}
+
+	public PtreeNode acquire(byte [] key) {
+		return acquire(key, maxKeyBits);
+	}
+	
+	public PtreeNode acquire(byte [] key, int key_bits) {
+		if (key_bits > maxKeyBits) {
+			return null;
+		}
+		
+		PtreeNode node = top;
+		PtreeNode match = null;
+		
+		while (node != null
+				&& node.keyBits <= key_bits
+				&& key_match(node.key, node.keyBits, key, key_bits) == true) {
+		    if (node.keyBits == key_bits) {
+				return addReference(node);
+			}
+
+			match = node;
+			
+			if (bit_check(key, node.keyBits) == true) {
+				node = node.right;
+			} else {
+				node = node.left;
+			}
+		}
+
+		PtreeNode add = null;
+		
+		if (node == null) {
+			add = new PtreeNode(key, key_bits, maxKeyOctets);
+			
+			if (match != null) {
+				node_link(match, add);
+			} else {
+				top = add;
+			}
+		} else {
+			add = node_common(node, key, key_bits);
+			if (add == null) {
+				return null;
+			}				
+			
+			if (match != null) {
+				node_link(match, add);
+			} else {
+				top = add;
+			}
+			node_link(add, node);
+			
+			if (add.keyBits != key_bits) {
+				match = add;
+				
+				add = new PtreeNode(key, key_bits, maxKeyOctets);
+				node_link(match, add);
+			}
+		}
+		
+		return addReference(add);
+	}
+
+	public PtreeNode lookup(byte [] key, int key_bits) {
+		if (key_bits > maxKeyBits) {
+			return null;
+		}
+		
+		PtreeNode node = top;
+		
+		while (node != null
+				&& node.keyBits <= key_bits
+				&& key_match(node.key, node.keyBits, key, key_bits) == true) {
+			if (node.keyBits == key_bits) {
+				return addReference(node);
+			}
+			
+			if (bit_check(key, node.keyBits) == true) {
+				node = node.right;
+			} else {
+				node = node.left;
+			}
+		}
+		return null;
+	}
+	
+	public PtreeNode match(byte [] key, int key_bits) {
+		if (key_bits > maxKeyBits) {
+			return null;
+		}
+		PtreeNode node = top;
+		PtreeNode matched = null;
+
+		if(node!=null)
+		
+		while (node != null
+				&& node.keyBits <= key_bits
+				&& key_match(node.key, node.keyBits, key, key_bits) == true) {
+			matched = node;
+			
+			if (bit_check(key, node.keyBits) == true) {
+				node = node.right;
+			} else {
+				node = node.left;
+			}
+		}
+		
+		if (matched != null) {
+			return addReference(matched);
+		}
+		
+		return null;
+	}
+	
+	public PtreeNode begin() {
+		if (top == null) {
+			return null;
+		}
+		return addReference(top);
+	}
+	
+	public PtreeNode next(PtreeNode node) {
+		PtreeNode next;
+		
+		if (node.left != null) {
+			next = node.left;
+			addReference(next);
+			delReference(node);
+			return next;
+		}
+		if (node.right != null) {
+			next = node.right;
+			addReference(next);
+			delReference(node);
+			return next;
+		}
+		
+		PtreeNode start = node;
+		while (node.parent != null) {
+			if (node.parent.left == node && node.parent.right != null) {
+				next = node.parent.right;
+				addReference(next);
+				delReference(start);
+				return next;
+			}
+			node = node.parent;
+		}
+		
+		delReference(start);
+		
+		return null;
+	}
+
+	static public int bit_to_octet(int key_bits) {
+		return Math.max((key_bits + 7) / 8, 1);
+	}
+
+	private PtreeNode addReference(PtreeNode node) {
+		node.refCount++;
+		return node;
+	}
+	
+	public void delReference(PtreeNode node) {
+		if (node.refCount > 0) {
+			node.refCount--;
+		}
+		if (node.refCount == 0) {
+			node_remove(node);
+		}
+	}
+	
+	private boolean key_match(byte [] key1, int key1_len, byte [] key2, int key2_len) {
+		int offset;
+		int shift;
+		
+		if (key1_len > key2_len) {
+			return false;
+		}
+		
+		offset = (Math.min(key1_len, key2_len)) / 8;
+		shift = (Math.min(key1_len, key2_len)) % 8;
+		
+		if (shift != 0) {
+			if ((maskBits[shift] & (key1[offset] ^ key2[offset])) != 0) {
+				return false;
+			}
+		}
+		
+		while (offset != 0) {
+			offset--;
+			if (key1[offset] != key2[offset]) {
+				return false;
+			}
+		}
+		return true;
+	}
+	
+	private boolean bit_check(byte [] key, int key_bits) {
+		int offset = key_bits / 8;
+		int shift = 7 - (key_bits % 8);
+		int bit = key[offset] & 0xff;
+
+		bit >>= shift;
+		
+		if ((bit & 1) == 1) {
+			return true;
+		} else {
+			return false;
+		}
+	}
+	
+	private void node_link(PtreeNode node, PtreeNode add) {
+		boolean bit = bit_check(add.key, node.keyBits);
+		
+		if (bit == true) {
+			node.right = add;
+		} else {
+			node.left = add;
+		}
+		add.parent = node;
+	}
+	
+	@SuppressWarnings("unused")
+    private PtreeNode node_common(PtreeNode node, byte [] key, int key_bits) {
+		int i;
+		int limit = Math.min(node.keyBits, key_bits) / 8;
+
+		for (i = 0; i < limit; i++) {
+			if (node.key[i] != key[i]) {
+				break;
+			}
+		}
+		
+		int common_len = i * 8;
+		int boundary = 0;
+
+		if (common_len != key_bits) {
+			byte diff = (byte)(node.key[i] ^ key[i]);
+			byte mask = (byte)0x80;
+			int shift_mask = 0;
+			
+			while (common_len < key_bits && ((mask & diff) == 0)) {
+				boundary = 1;
+
+				shift_mask = (mask & 0xff);
+				shift_mask >>= 1;
+				mask = (byte)shift_mask;
+
+				common_len++;
+			}
+		}
+		
+		PtreeNode add = new PtreeNode(null, common_len, maxKeyOctets);
+		if (add == null)
+			return null;
+		
+		int j;
+		for (j = 0; j < i; j++)
+			add.key[j] = node.key[j];
+
+		if (boundary != 0)
+			add.key[j] = (byte)(node.key[j] & maskBits[add.keyBits % 8]);
+		
+		return add;
+	}
+	
+	private void node_remove(PtreeNode node) {
+		PtreeNode child;
+		PtreeNode parent;
+		
+		if (node.left != null && node.right != null) {
+			return;
+		}
+		
+		if (node.left != null) {
+			child = node.left;
+		} else {
+			child = node.right;
+		}
+		
+		parent = node.parent;
+		
+		if (child != null) {
+			child.parent = parent;
+		}
+		
+		if (parent != null) {
+			if (parent.left == node) {
+				parent.left = child;
+			} else {
+				parent.right = child;
+			}
+		} else {
+			top = child;
+		}
+		
+		if (parent != null && parent.refCount == 0) {
+			node_remove(parent);
+		}
+	}
+}