diff options
author | Quentin Young <qlyoung@cumulusnetworks.com> | 2019-12-18 20:09:31 +0100 |
---|---|---|
committer | Quentin Young <qlyoung@cumulusnetworks.com> | 2019-12-18 21:13:51 +0100 |
commit | 11bc3dba8605da0bce753935d20c0712a2c5dcd0 (patch) | |
tree | d42b6ded8d6f8df167b397cf96918e47753ac9e7 /doc | |
parent | Merge pull request #5552 from sworleys/NHG-Set-RTNH_F_ONLINK (diff) | |
download | frr-11bc3dba8605da0bce753935d20c0712a2c5dcd0.tar.xz frr-11bc3dba8605da0bce753935d20c0712a2c5dcd0.zip |
doc: update overview.rst for the new millennium
Provide a more succinct summary of what FRR is, what it does, where it
sits in the network stack. Also remove some outdated comments about
features.
Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
Diffstat (limited to 'doc')
-rw-r--r-- | doc/user/overview.rst | 142 |
1 files changed, 64 insertions, 78 deletions
diff --git a/doc/user/overview.rst b/doc/user/overview.rst index 03d7299bf..db490b518 100644 --- a/doc/user/overview.rst +++ b/doc/user/overview.rst @@ -4,65 +4,23 @@ Overview ******** -`FRR`_ is a routing software package that provides TCP/IP based routing -services with routing protocols support such as BGP, RIP, OSPF, IS-IS and more -(see :ref:`supported-protocols`). FRR also supports -special BGP Route Reflector and Route Server behavior. In addition to -traditional IPv4 routing protocols, FRR also supports IPv6 routing protocols. -With an SNMP daemon that supports the AgentX protocol, FRR provides routing -protocol MIB read-only access (:ref:`snmp-support`). - -FRR uses an advanced software architecture to provide you with a high quality, -multi server routing engine. FRR has an interactive user interface for each -routing protocol and supports common client commands. Due to this design, you -can add new protocol daemons to FRR easily. You can use FRR library as your -program's client user interface. - -FRR is distributed under the GNU General Public License. +`FRR`_ is a fully featured, high performance, free software IP routing suite. -FRR is a fork of `Quagga <http://www.quagga.net/>`_. +FRR implements all standard routing protocols such as BGP, RIP, OSPF, IS-IS and +more (see :ref:`feature-matrix`), as well as many of their extensions. -.. _about-frr: +FRR is a high performance suite written primarily in C. It can easily handle +full Internet routing tables and is suitable for use on hardware ranging from +cheap SBCs to commercial grade routers. It is actively used in production by +hundreds of companies, universities, research labs and governments. -About FRR -========= +FRR is distributed under GPLv2, with development modeled after the Linux +kernel. Anyone may contribute features, bug fixes, tools, documentation +updates, or anything else. -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 FRR installed acts as a dedicated router. With FRR, your machine -exchanges routing information with other routers using routing protocols. FRR -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 FRR terminal interface. - -Adding to routing protocol support, FRR 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 FRR 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 FRR's dynamic routing protocol support for protocols such as -RIP, OSPF, IS-IS or BGP. - -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. FRR has a -different system administration method. There are two user modes in FRR. 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, FRR supports common unicast routing protocols, that is BGP, OSPF, -RIP and IS-IS. Upcoming for MPLS support, an implementation of LDP is -currently being prepared for merging. Implementations of BFD and PIM-SSM -(IPv4) also exist, but are not actively being worked on. - -The ultimate goal of the FRR project is making a production-grade, high -quality, featureful and free IP routing software suite. +FRR is a fork of `Quagga <http://www.quagga.net/>`_. +.. _how-to-get-frr: How to get FRR ============== @@ -79,25 +37,46 @@ For instructions on installing from source, refer to the `developer documentation <http://docs.frrouting.org/projects/dev-guide/en/latest/>`_. +.. _about-frr: + +About FRR +========= + +FRR provides IP routing services. Its role in a networking stack is to exchange +routing information with other routers, make routing and policy decisions, and +inform other layers of these decisions. In the most common scenario, FRR +installs routing decisions into the OS kernel, allowing the kernel networking +stack to make the corresponding forwarding decisions. + +In addition to dynamic routing FRR supports the full range of L3 configuration, +including static routes, addresses, router advertisements etc. It has some +light L2 functionality as well, but this is mostly left to the platform. This +makes it suitable for deployments ranging from small home networks with static +routes to Internet exchanges running full Internet tables. + +FRR runs on all modern \*NIX operating systems, including Linux and the BSDs. +Feature support varies by platform; see the :ref:`feature-matrix`. + + System Architecture -=================== +------------------- .. index:: System architecture - .. index:: Software architecture - .. index:: Software internals Traditional routing software is made as a one process program which provides all of the routing protocol functionalities. FRR takes a different approach. -FRR is a suite of daemons that work together to build the routing table. There -is a daemon for each major supported protocol as well as a middleman daemon -(*Zebra*) which serves as the broker between these daemons and the kernel. +FRR is a suite of daemons that work together to build the routing table. Each +major protocol is implemented in its own daemon, and these daemons talk to a +middleman daemon (*zebra*), which is responsible for coordinating routing +decisions and talking to the dataplane. This architecture allows for high resiliency, since an error, crash or exploit -in one protocol daemon will generally not affect the others. It is also +in one protocol daemon will generally not affect the others. It is also flexible and extensible since the modularity makes it easy to implement new -protocols and tie them into the suite. +protocols and tie them into the suite. Additionally, each daemon implements a +plugin system allowing new functionality to be loaded at runtime. An illustration of the large scale architecture is given below. @@ -121,17 +100,23 @@ An illustration of the large scale architecture is given below. +-------------+ +------------------+ +-------------+ -The multi-process architecture brings extensibility, modularity and -maintainability. All of the FRR daemons can be managed through a single -integrated user interface shell called *vtysh*. *vtysh* connects to each -daemon through a UNIX domain socket and then works as a proxy for user input. -In addition to a unified frontend, *vtysh* also provides the ability to -configure all the daemons using a single configuration file through the -integrated configuration mode avoiding the problem of having to maintain a -separate configuration file for each daemon. +All of the FRR daemons can be managed through a single integrated user +interface shell called *vtysh*. *vtysh* connects to each daemon through a UNIX +domain socket and then works as a proxy for user input. In addition to a +unified frontend, *vtysh* also provides the ability to configure all the +daemons using a single configuration file through the integrated configuration +mode. This avoids the overhead of maintaining a separate configuration file for +each daemon. + +FRR is currently currently implementing a new internal configuration system +based on YANG data models. When this work is completed, FRR will be a fully +programmable routing stack. + + +.. _supported-platforms: Supported Platforms -=================== +------------------- .. index:: Supported platforms .. index:: FRR on other systems @@ -150,7 +135,7 @@ us know if you can get FRR to run on a platform which is not listed below: Versions of these platforms that are older than around 2 years from the point of their original release (in case of GNU/Linux, this is since the kernel's -release on https://kernel.org/) may need some work. Similarly, the following +release on https://kernel.org/) may need some work. Similarly, the following platforms may work with some effort: - Solaris @@ -162,14 +147,15 @@ Recent versions of the following compilers are well tested: - LLVM's Clang - Intel's ICC -.. _supported-protocols: +.. _feature-matrix: -Supported Protocols vs. Platform -================================ +Feature Matrix +^^^^^^^^^^^^^^ -The following table lists all protocols cross-refrenced to all operating -systems that have at least CI build tests. Note that for features, only -features with system dependencies are included here. +The following table lists all protocols cross-referenced to all operating +systems that have at least CI build tests. Note that for features, only +features with system dependencies are included here; if you don't see the +feature you're interested in, it should be supported on your platform. .. role:: mark |