hii... I am new to open source and want to build a complete billing ,subscribing and bandwidth management system, for own ISP which also should support load balancing,RADIUS etc.I have three internet lines available. I've searched in may forums and found followings are used in opensource, freeradius,mikrotik squid-proxy,zeroshell,pfsense,clearOS etc. The problem is i don't have the idea about basic flow or some structure type.So if anyone can help me to design a flow which should be placed .As i want to go completely on opensource.On some forums and search i've found that i should have following. bandwidth management server(may be zeroshell or pfsense) central database server-(LDAP or mysql) Account and billing management server-(radiusmanager,daloradius,) RADIUS server-(freeradius or inbuilt radius in zeroshell) firewall(inbuilt in zeroshell) application server(any for authentication of users like php) Log and reporting server and i've searched on the net for its open-source versions. The problem is how to use and integrate all these to build structure? Hardware cost is no problem. Any pointer should be appreciated. Thanks in advance.