public void addLSA(IP neighbor, LSAMessage message)
	{
		try {
			lock.lock();
			LSAMessage oldMessage = table.get(neighbor);
			if (oldMessage == null || 
					oldMessage.sequenceNumber() < message.sequenceNumber()) {
				table.put(neighbor, message);
				if (!message.equals(oldMessage)) {
					routingTable.updateGraph(this);
					routingTable.writeTable();
				}
			}
		}
		finally {
			lock.unlock();
		}
	}