XORP pronounced as "Zorp" is eXtensible Open Router Platform.
XORP is an extensible open source routing platform released under a BSD style License. While designed for extensibility, XORP provides a fully featured platform that implements IPv4 and IPv6 routing protocols and a unified platform to configure them. Vyatta Opensource router implements XORP routing platform. XORP is the only open source platform to offer integrated multicast capability. XORP's modular architecture allows rapid introduction of new protocols, features and functionality, including support for custom hardware and software forwarding.
The latest stable version of XORP is 1.4 and there is a XORP Live CD that can boot a PC with it and run without having to do any installations. When running the Live CD any config changes can be saved to a Floppy disk (if a Floppy disk exist on the PC). XORP can run on all BSD distributions and most of the LINUX distributions, MacOSX and on Windows.
XORP has a JunOS style CLI to configure and manage the router as against the Cisco style and maintains a single config file.
The following are the protocols are supported on XORP:
BGP4+ (IPv4 and IPv6 versions)
OSPFv2 and OSPFv3
RIP for IPv4 and RIPng for IPv6
The performance of PC-based XORP implementations depends on the forwarding capability of the underlying hardware. For higher bandwidth requirement or greater speed, XORP can be used as a software stack for controlling advanced hardware forwarding planes. Its Forwarding Engine Abstraction (FEA) process provides a key abstraction layer that isolates higher level routing functionality from the underlying operating system and forwarding engines. This makes it straightforward to port XORP to new hardware platforms using software shims.
XORP also supports third party integrations using its API's making it completely transparent from the outside.
While XORP is a great open platform for research, it is stable and is of production quality to run live routing systems. For more information, FAQs and installation procedures please visit the XORP homepage here.