netgraph is the graph

Graph (mathematics)

In mathematics, a graph is an abstract representation of a set of objects where some pairs of the objects are connected by links. The interconnected objects are represented by mathematical abstractions called vertices, and the links that connect some pairs of vertices are called edges...

 based kernel networking subsystem of FreeBSD

FreeBSD

FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...

. Netgraph provides support for L2TP

L2TP

In computer networking, Layer 2 Tunneling Protocol is a tunneling protocol used to support virtual private networks . It does not provide any encryption or confidentiality by itself; it relies on an encryption protocol that it passes within the tunnel to provide privacy.-History:Published in 1999...

, PPTP, ATM

Asynchronous Transfer Mode

Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...

, bluetooth

Bluetooth

Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...

 using a modular set of nodes that are the graph.

Netgraph has also been ported on other Operating Systems:

• NetBSD
  NetBSD
  NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...
  
   http://mail-index.netbsd.org/tech-net/2001/08/17/0000.html (not integrated into mainline kernel)
• Linux
  Linux
  Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
  
   kernel 2.4 and 2.6 by 6WIND (Commercial closed source port)
• Linux
  Linux
  Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
  
   kernel 3.0 by LANA

History

Netgraph was originally designed and implemented at Whistle Communications by Julian Elischer and Archie Cobbs for the Whistle InterJet small office router product. The purpose of the project was to create a flexible framework for implementing new networking protocols. Key requirements included the ability to prototype with user-space programs while still retaining the ability to interact with data flows normally hidden within the kernel.

External links

• netgraph man page