diff --git a/src/main/java/net/onrc/onos/ofcontroller/bgproute/Prefix.java b/src/main/java/net/onrc/onos/ofcontroller/bgproute/Prefix.java
index 54775df..c40214b 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/bgproute/Prefix.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/bgproute/Prefix.java
@@ -2,30 +2,89 @@
 
 import java.net.InetAddress;
 import java.net.UnknownHostException;
+import java.util.Arrays;
 
 public class Prefix {
-	private int prefixLength;
-	private InetAddress address;
+	private final int MAX_BYTES = 4;
+	
+	private final int prefixLength;
+	private final byte[] address;
+	
+	//For verifying the arguments and pretty printing
+	private final InetAddress inetAddress;
+	
+	public Prefix(byte[] addr, int prefixLength) {
+		if (addr == null || addr.length != MAX_BYTES || 
+				prefixLength < 0 || prefixLength > MAX_BYTES * Byte.SIZE) {
+			throw new IllegalArgumentException();
+		}
 
-	public Prefix(byte[] addr, int prefixLength) throws UnknownHostException {
-		//try {
-		address = InetAddress.getByAddress(addr);
-		//} catch (UnknownHostException e) {
-		//	System.out.println("InetAddress exception");
-		//	return;
-		//}
+		address = canonicalizeAddress(addr, prefixLength);
 		this.prefixLength = prefixLength;
-		//System.out.println(address.toString() + "/" + prefixLength);
+		
+		try {
+			inetAddress = InetAddress.getByAddress(address);
+		} catch (UnknownHostException e) {
+			throw new IllegalArgumentException();
+		}
 	}
 
-	public Prefix(String str, int prefixLength) throws UnknownHostException {
-		//try {
-		address = InetAddress.getByName(str);
-		//} catch (UnknownHostException e) {
-		//	System.out.println("InetAddress exception");
-		//	return;
-		//}
+	public Prefix(String strAddress, int prefixLength) {
+		byte[] addr = null;
+		try {
+			addr = InetAddress.getByName(strAddress).getAddress();
+		} catch (UnknownHostException e) {
+			throw new IllegalArgumentException("Invalid IP inetAddress argument");
+		}
+				
+		if (addr == null || addr.length != MAX_BYTES || 
+				prefixLength < 0 || prefixLength > MAX_BYTES * Byte.SIZE) {
+			throw new IllegalArgumentException();
+		}
+		
+		address = canonicalizeAddress(addr, prefixLength);
 		this.prefixLength = prefixLength;
+		
+		try {
+			inetAddress = InetAddress.getByAddress(address);
+		} catch (UnknownHostException e) {
+			throw new IllegalArgumentException();
+		}
+	}
+	
+	private byte[] canonicalizeAddress(byte[] address, int prefixLength) {
+		byte[] result = new byte[address.length];
+		
+		if (prefixLength == 0) {
+			for (int i = 0; i < MAX_BYTES; i++) {
+				result[i] = 0;
+			}
+			
+			return result;
+		}
+		
+		result = Arrays.copyOf(address, address.length);
+		
+		//Set all bytes after the end of the prefix to 0
+		int lastByteIndex = (prefixLength - 1) / Byte.SIZE;
+		for (int i = lastByteIndex; i < MAX_BYTES; i++) {
+			result[i] = 0;
+		}
+		
+		byte lastByte = address[lastByteIndex];
+		byte mask = 0;
+		byte lsb = 1;
+		int lastBit = (prefixLength - 1) % Byte.SIZE;
+		for (int i = 0; i < Byte.SIZE; i++) {
+			if (i <= lastBit + 1) {
+				mask |= lsb;
+			}
+			mask <<= 1;
+		}
+
+		result[lastByteIndex] = (byte) (lastByte & mask);
+		
+		return result;
 	}
 
 	public int getPrefixLength() {
@@ -33,7 +92,7 @@
 	}
 	
 	public byte[] getAddress() {
-		return address.getAddress();
+		return address;
 	}
 	
 	@Override
@@ -44,7 +103,7 @@
 		
 		Prefix otherPrefix = (Prefix) other;
 		
-		return (address.equals(otherPrefix.address)) && 
+		return (Arrays.equals(address, otherPrefix.address)) &&
 				(prefixLength == otherPrefix.prefixLength);
 	}
 	
@@ -52,12 +111,28 @@
 	public int hashCode() {
 		int hash = 17;
 		hash = 31 * hash + prefixLength;
-		hash = 31 * hash + (address == null ? 0 : address.hashCode());
+		hash = 31 * hash + Arrays.hashCode(address);
 		return hash;
 	}
 	
 	@Override
 	public String toString() {
-		return address.getHostAddress() + "/" + prefixLength;
+		return inetAddress.getHostAddress() + "/" + prefixLength;
+	}
+	
+	public String printAsBits() {
+		String result = "";
+		for (int i = 0; i < address.length; i++) {
+			byte b = address[i];
+			for (int j = 0; j < Byte.SIZE; j++) {
+				byte mask = (byte) (0x80 >>> j);
+				result += ((b & mask) == 0)? "0" : "1";
+				if (i*Byte.SIZE+j == prefixLength-1) {
+					return result;
+				}
+			}
+			result += " ";
+		}
+		return result.substring(0, result.length() - 1);
 	}
 }