Today, TCP/IP networks are covering all of the world. The Internet has been deployed in many countries, companies, and to the home. When you connect to the Internet your packet will pass many routers which have TCP/IP routing functionality.
A system with Quagga installed acts as a dedicated router. With Quagga, your machine exchanges routing information with other routers using routing protocols. Quagga uses this information to update the kernel routing table so that the right data goes to the right place. You can dynamically change the configuration and you may view routing table information from the Quagga terminal interface.
Adding to routing protocol support, Quagga can setup interface's flags, interface's address, static routes and so on. If you have a small network, or a stub network, or xDSL connection, configuring the Quagga routing software is very easy. The only thing you have to do is to set up the interfaces and put a few commands about static routes and/or default routes. If the network is rather large, or if the network structure changes frequently, you will want to take advantage of Quagga's dynamic routing protocol support for protocols such as RIP, OSPF or BGP. Quagga is with you.
Traditionally, UNIX based router configuration is done by ifconfig and route commands. Status of routing table is displayed by netstat utility. Almost of these commands work only if the user has root privileges. Quagga has a different system administration method. There are two user modes in Quagga. One is normal mode, the other is enable mode. Normal mode user can only view system status, enable mode user can change system configuration. This UNIX account independent feature will be great help to the router administrator.
Currently, Quagga supports common unicast routing protocols. Multicast routing protocols such as BGMP, PIM-SM, PIM-DM may be supported in Quagga 2.0. MPLS support is going on. In the future, TCP/IP filtering control, QoS control, diffserv configuration will be added to Quagga. Quagga project's final goal is making a productive, quality free TCP/IP routing software.