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.

System Requirements

System resources needed by FRR are highly dependent on workload. Routing software performance is particularly susceptible to external factors such as:

  • Kernel networking stack

  • Physical NIC

  • Peer behavior

  • Routing information scale

Because of these factors - especially the last one - it's difficult to lay out resource requirements.

To put this in perspective, FRR can be run on very low resource systems such as SBCs, provided it is not stressed too much. If you want to set up 4 Raspberry Pis to play with BGP or OSPF, it should work fine. If you ask a FRR to process a complete internet routing table on a Raspberry Pi, you will be disappointed. However, given enough resources, FRR ought to be capable of acting as a core IX router. Such a use case requires at least 4gb of memory and a recent quad-core server processor at a minimum.

If you are new to networking, an important thing to remember is that FRR is control plane software. It does not itself forward packets - it exchanges information with peers about how to forward packets. Forwarding plane performance largely depends on choice of NIC / ASIC.

Architecture

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. 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 flexible and extensible since the modularity makes it easy to implement new 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.

+----+  +----+  +-----+  +----+  +----+  +----+  +-----+
|bgpd|  |ripd|  |ospfd|  |ldpd|  |pbrd|  |pimd|  |.....|
+----+  +----+  +-----+  +----+  +----+  +----+  +-----+
     |       |        |       |       |       |        |
+----v-------v--------v-------v-------v-------v--------v
|                                                      |
|                         Zebra                        |
|                                                      |
+------------------------------------------------------+
       |                    |                   |
       |                    |                   |
+------v------+   +---------v--------+   +------v------+
|             |   |                  |   |             |
| *NIX Kernel |   | Remote dataplane |   | ........... |
|             |   |                  |   |             |
+-------------+   +------------------+   +-------------+

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 implementing a new internal configuration system based on YANG data models. When this work is completed, FRR will be a fully programmable routing stack.

Platform Support

Currently FRR supports GNU/Linux and BSD. Porting FRR to other platforms is not too difficult as platform dependent code should be mostly limited to the Zebra daemon. Protocol daemons are largely platform independent. Please let us know if you can get FRR to run on a platform which is not listed below:

  • GNU/Linux

  • FreeBSD

  • NetBSD

  • OpenBSD

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 platforms may work with some effort:

  • MacOS

Recent versions of the following compilers are well tested:

  • GNU's GCC

  • LLVM's Clang

  • Intel's ICC

Unsupported Platforms

In General if the platform you are attempting to use is not listed above then FRR does not support being run on that platform. The only caveat here is that version 7.5 and before Solaris was supported in a limited fashion.

Feature Matrix

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.

Daemon / Feature

Linux

OpenBSD

FreeBSD

NetBSD

FRR Core

zebra

Y

Y

Y

Y

VRF

>=4.8

N

N

N

MPLS

>=4.5

Y

N

N

pbrd (Policy Routing)

Y

N

N

N

WAN / Carrier protocols

bgpd (BGP)

Y

Y

Y

Y

VRF / L3VPN

>=4.8 †4.3

CP

CP

CP

EVPN

>=4.18 †4.9

CP

CP

CP

VNC (Virtual Network Control)

CP

CP

CP

CP

Flowspec

CP

CP

CP

CP

ldpd (LDP)

>=4.5

Y

N

N

VPWS / PW

N

>=5.8

N

N

VPLS

N

>=5.8

N

N

nhrpd (NHRP)

Y

N

N

N

Link-State Routing

ospfd (OSPFv2)

Y

Y

Y

Y

Segment Routing

>=4.12

N

N

N

ospf6d (OSPFv3)

Y

Y

Y

Y

isisd (IS-IS)

Y

Y

Y

Y

Distance-Vector Routing

ripd (RIPv2)

Y

Y

Y

Y

ripngd (RIPng)

Y

Y

Y

Y

babeld (BABEL)

Y

Y

Y

Y

eigrpd (EIGRP)

Y

Y

Y

Y

Multicast Routing

pimd (PIM)

>=4.19

N

Y

Y

SSM (Source Specific)

Y

N

Y

Y

ASM (Any Source)

Y

N

N

N

EVPN BUM Forwarding

>=5.0

N

N

N

vrrpd (VRRP)

>=5.1

N

N

N

The indicators have the following semantics:

  • Y - daemon/feature fully functional

  • >=X.X - fully functional with kernel version X.X or newer

  • †X.X - restricted functionality or impaired performance with kernel version X.X or newer

  • CP - control plane only (i.e. BGP route server / route reflector)

  • N - daemon/feature not supported by operating system

Known Kernel Issues

  • Linux < 4.11

    v6 Route Replacement - Linux kernels before 4.11 can cause issues with v6 route deletion when you have ECMP routes installed into the kernel. This especially becomes apparent if the route is being transformed from one ECMP path to another.

Supported RFCs

FRR implements the following RFCs:

Note

This list is incomplete.

BGP

  • RFC 1771 A Border Gateway Protocol 4 (BGP-4). Y. Rekhter & T. Li. March 1995.

  • RFC 1965 Autonomous System Confederations for BGP. P. Traina. June 1996.

  • RFC 1997 BGP Communities Attribute. R. Chandra, P. Traina & T. Li. August 1996.

  • RFC 1998 An Application of the BGP Community Attribute in Multi-home Routing. E. Chen, T. Bates. August 1996.

  • RFC 2385 Protection of BGP Sessions via the TCP MD5 Signature Option. A. Heffernan. August 1998.

  • RFC 2439 BGP Route Flap Damping. C. Villamizar, R. Chandra, R. Govindan. November 1998.

  • RFC 2545 Use of BGP-4 Multiprotocol Extensions for IPv6 Inter-Domain Routing. P. Marques, F. Dupont. March 1999.

  • RFC 2796 BGP Route Reflection An alternative to full mesh IBGP. T. Bates & R. Chandrasekeran. June 1996.

  • RFC 2842 Capabilities Advertisement with BGP-4. R. Chandra, J. Scudder. May 2000.

  • RFC 2858 Multiprotocol Extensions for BGP-4. T. Bates, Y. Rekhter, R. Chandra, D. Katz. June 2000.

  • RFC 2918 Route Refresh Capability for BGP-4. E. Chen, September 2000.

  • RFC 3107 Carrying Label Information in BGP-4. Y. Rekhter & E. Rosen. May 2001.

  • RFC 3765 NOPEER Community for Border Gateway Protocol (BGP) Route Scope Control. G.Huston. April 2001.

  • RFC 4271 A Border Gateway Protocol 4 (BGP-4). Updates RFC1771. Y. Rekhter, T. Li & S. Hares. January 2006.

  • RFC 4360 BGP Extended Communities Attribute. S. Sangli, D. Tappan, Y. Rekhter. February 2006.

  • RFC 4364 BGP/MPLS IP Virtual Private Networks (VPNs). Y. Rekhter. February 2006.

  • RFC 4456 BGP Route Reflection An alternative to full mesh IBGP. T. Bates, E. Chen, R. Chandra. April 2006.

  • RFC 4486 Subcodes for BGP Cease Notification Message. E. Chen, V. Gillet. April 2006.

  • RFC 4659 BGP-MPLS IP Virtual Private Network (VPN) Extension for IPv6 VPN. J. De Clercq, D. Ooms, M. Carugi, F. Le Faucheur. September 2006.

  • RFC 4724 Graceful Restart Mechanism for BGP. S. Sangli, E. Chen, R. Fernando, J. Scudder, Y. Rekhter. January 2007.

  • RFC 4760 Multiprotocol Extensions for BGP-4. T. Bates, R. Chandra, D. Katz, Y. Rekhter. January 2007.

  • RFC 4893 BGP Support for Four-octet AS Number Space. Q. Vohra, E. Chen May 2007.

  • RFC 5004 Avoid BGP Best Path Transitions from One External to Another. E. Chen & S. Sangli. September 2007 (Partial support).

  • RFC 5065 Autonomous System Confederations for BGP. P. Traina, D. McPherson, J. Scudder. August 2007.

  • RFC 5082 The Generalized TTL Security Mechanism (GTSM). V. Gill, J. Heasley, D. Meyer, P. Savola, C. Pingnataro. October 2007.

  • RFC 5291 Outbound Route Filtering Capability. E. Chen, Y. Rekhter. August 2008.

  • RFC 5292 Address-Prefix-Based Outbound Route Filter for BGP-4. E. Chen, S. Sangli. August 2008.

  • RFC 5396 Textual Representation of Autonomous System (AS) Numbers. G. Michaelson, G. Huston. December 2008.

  • RFC 5492 Capabilities Advertisement with BGP-4. J. Scudder, R. Chandra. February 2009.

  • RFC 5575 Dissemination of Flow Specification Rules. P. Marques, N. Sheth, R. Raszuk, B. Greene, J. Mauch, D. McPherson. August 2009.

  • RFC 5668 4-Octet AS Specific BGP Extended Community. Y. Rekhter, S. Sangli, D. Tappan October 2009.

  • RFC 5701 IPv6 Address Specific BGP Extended Community Attribute. Y. Rekhter. 2009.

  • RFC 6286 Autonomous-System-Wide Unique BGP Identifier for BGP-4. E. Chen, J. Yuan. June 2011.

  • RFC 6472 Recommendation for Not Using AS_SET and AS_CONFED_SET in BGP. W. Kumari, K. Sriram. December 2011.

  • RFC 6608 Subcodes for BGP Finite State Machine Error. J. Dong, M. Chen, Huawei Technologies, A. Suryanarayana, Cisco Systems. May 2012.

  • RFC 6810 The Resource Public Key Infrastructure (RPKI) to Router Protocol. R. Bush, R. Austein. January 2013.

  • RFC 6811 BGP Prefix Origin Validation. P. Mohapatra, J. Scudder, D. Ward, R. Bush, R. Austein. January 2013.

  • RFC 6938 Deprecation of BGP Path Attributes: DPA, ADVERTISER, and RCID_PATH / CLUSTER_ID. J. Scudder. May 2013.

  • RFC 6996 Autonomous System (AS) Reservation for Private Use. J. Mitchell. July 2013.

  • RFC 7196 Making Route Flap Damping Usable. C. Pelsser, R. Bush, K. Patel, P. Mohapatra, O. Maennel. May 2014.

  • RFC 7300 Reservation of Last Autonomous System (AS) Numbers. J. Haas, J. Mitchell. July 2014.

  • RFC 7311 The Accumulated IGP Metric Attribute for BGP. P. Mohapatra, R. Fernando, E. Rosen, J. Uttaro. August 2014.

  • RFC 7313 Enhanced Route Refresh Capability for BGP-4. K. Patel, E. Chen, B. Venkatachalapathy. July 2014.

  • RFC 7606 Revised Error Handling for BGP UPDATE Messages. E. Chen, J. Scudder, P. Mohapatra, K. Patel. August 2015.

  • RFC 7607 Codification of AS 0 Processing. W. Kumari, R. Bush, H. Schiller, K. Patel. August 2015.

  • RFC 7611 BGP ACCEPT_OWN Community Attribute. J. Uttaro, P. Mohapatra, D. Smith, R. Raszuk, J. Scudder. August 2015.

  • RFC 7911 Advertisement of Multiple Paths in BGP. D. Walton, A. Retana, E. Chen, J. Scudder. July 2016.

  • RFC 7947 Internet Exchange BGP Route Server. E. Jasinska, N. Hilliard, R. Raszuk, N. Bakker. September 2016.

  • RFC 7999 BLACKHOLE Community. T. King, C. Dietzel, J. Snijders, G. Doering, G. Hankins. October 2016.

  • RFC 8050 Multi-Threaded Routing Toolkit (MRT) Routing Information Export Format with BGP Additional Path Extensions. C. Petrie, T. King. May 2017.

  • RFC 8092 BGP Large Communities Attribute. J. Heitz, Ed., J. Snijders, Ed, K. Patel, I. Bagdonas, N. Hilliard. February 2017.

  • RFC 8093 Deprecation of BGP Path Attribute Values 30, 31, 129, 241, 242, and 243. J. Snijders. February 2017.

  • RFC 8097 BGP Prefix Origin Validation State Extended Community. P. Mohapatra, K. Patel, J. Scudder, D. Ward, R. Bush. March 2017.

  • RFC 8195 Use of BGP Large Communities. J. Snijders, J. Heasley, M. Schmidt. June 2017.

  • RFC 8203 BGP Administrative Shutdown Communication. J. Snijders, J. Heitz, J. Scudder. July 2017.

  • RFC 8212 Default External BGP (EBGP) Route Propagation Behavior without Policies. J. Mauch, J. Snijders, G. Hankins. July 2017.

  • RFC 8277 Using BGP to Bind MPLS Labels to Address Prefixes. E. Rosen. October 2017.

  • RFC 8538 Notification Message Support for BGP Graceful Restart. K. Patel, R. Fernando, J. Scudder, J. Haas. March 2019.

  • RFC 8654 Extended Message Support for BGP. R. Bush, K. Patel, D. Ward. October 2019.

  • RFC 9003 Extended BGP Administrative Shutdown Communication. J. Snijders, J. Heitz, J. Scudder, A. Azimov. January 2021.

  • RFC 9012 The BGP Tunnel Encapsulation Attribute. K. Patel, G. Van de Velde, S. Sangli, J. Scudder. April 2021.

  • RFC 9072 Extended Optional Parameters Length for BGP OPEN Message. E. Chen, J. Scudder. July 2021.

  • RFC 9234 Route Leak Prevention and Detection Using Roles in UPDATE and OPEN Messages. A. Azimov, E. Bogomazov, R. Bush, K. Patel, K. Sriram. May 2022.

  • RFC 9384 A BGP Cease NOTIFICATION Subcode for Bidirectional Forwarding Detection (BFD). J. Haas. March 2023.

  • RFC 9494 Long-Lived Graceful Restart for BGP. J. Uttaro, E. Chen, B. Decraene, J. Scudder. November 2023.

  • RFC 9687 Border Gateway Protocol 4 (BGP-4) Send Hold Timer. J. Snijders, B. Cartwright-Cox, Y. Qu. November 2024.

  • RFC 9774 Deprecation of AS_SET and AS_CONFED_SET in BGP. W. Kumari, K. Sriram, L. Hannachi, J. Haas. May 2025.

OSPF

  • RFC 2328 OSPF Version 2. J. Moy. April 1998.

  • RFC 2370 The OSPF Opaque LSA Option R. Coltun. July 1998.

  • RFC 3101 The OSPF Not-So-Stubby Area (NSSA) Option P. Murphy. January 2003.

  • RFC 2740 OSPF for IPv6. R. Coltun, D. Ferguson, J. Moy. December 1999.

  • RFC 3137 OSPF Stub Router Advertisement, A. Retana, L. Nguyen, R. White, A. Zinin, D. McPherson. June 2001

ISIS

RIP

  • RFC 1058 Routing Information Protocol. C.L. Hedrick. Jun-01-1988.

  • RFC 2082 RIP-2 MD5 Authentication. F. Baker, R. Atkinson. January 1997.

  • RFC 2453 RIP Version 2. G. Malkin. November 1998.

  • RFC 2080 RIPng for IPv6. G. Malkin, R. Minnear. January 1997.

PIM

BFD

  • RFC 5880 Bidirectional Forwarding Detection (BFD), D. Katz, D. Ward. June 2010

  • RFC 5881 Bidirectional Forwarding Detection (BFD) for IPv4 and IPv6 (Single Hop), D. Katz, D. Ward. June 2010

  • RFC 5882 Generic Application of Bidirectional Forwarding Detection (BFD), D. Katz, D. Ward. June 2010

  • RFC 5883 Bidirectional Forwarding Detection (BFD) for Multihop Paths, D. Katz, D. Ward. June 2010

MPLS

  • RFC 2858 Multiprotocol Extensions for BGP-4. T. Bates, Y. Rekhter, R. Chandra, D. Katz. June 2000.

  • RFC 4364 BGP/MPLS IP Virtual Private Networks (VPNs). Y. Rekhter. Feb 2006.

  • RFC 4447 Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP), L. Martini, E. Rosen, N. El-Aawar, T. Smith, and G. Heron. April 2006.

  • RFC 4659 BGP-MPLS IP Virtual Private Network (VPN) Extension for IPv6 VPN. J. De Clercq, D. Ooms, M. Carugi, F. Le Faucheur. September 2006

  • RFC 4762 Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling, M. Lasserre and V. Kompella. January 2007.

  • RFC 5036 LDP Specification, L. Andersson, I. Minei, and B. Thomas. October 2007.

  • RFC 5561 LDP Capabilities, B. Thomas, K. Raza, S. Aggarwal, R. Aggarwal, and JL. Le Roux. July 2009.

  • RFC 5918 Label Distribution Protocol (LDP) 'Typed Wildcard' Forward Equivalence Class (FEC), R. Asati, I. Minei, and B. Thomas. August 2010.

  • RFC 5919 Signaling LDP Label Advertisement Completion, R. Asati, P. Mohapatra, E. Chen, and B. Thomas. August 2010.

  • RFC 6667 LDP 'Typed Wildcard' Forwarding Equivalence Class (FEC) for PWid and Generalized PWid FEC Elements, K. Raza, S. Boutros, and C. Pignataro. July 2012.

  • RFC 6720 The Generalized TTL Security Mechanism (GTSM) for the Label Distribution Protocol (LDP), C. Pignataro and R. Asati. August 2012.

  • RFC 7552 Updates to LDP for IPv6, R. Asati, C. Pignataro, K. Raza, V. Manral, and R. Papneja. June 2015.

VRRP

  • RFC 3768 Virtual Router Redundancy Protocol (VRRP). R. Hinden. April 2004.

  • RFC 5798 Virtual Router Redundancy Protocol (VRRP) Version 3 for IPv4 and IPv6. S. Nadas. June 2000.

SNMP

When SNMP support is enabled, the following RFCs are also supported:

  • RFC 1227 SNMP MUX protocol and MIB. M.T. Rose. May-01-1991.

  • RFC 1657 Definitions of Managed Objects for the Fourth Version of the Border Gateway Protocol (BGP-4) using SMIv2. S. Willis, J. Burruss, J. Chu, Editor. July 1994.

  • RFC 1724 RIP Version 2 MIB Extension. G. Malkin & F. Baker. November 1994.

  • RFC 1850 OSPF Version 2 Management Information Base. F. Baker, R. Coltun. November 1995.

  • RFC 2741 Agent Extensibility (AgentX) Protocol. M. Daniele, B. Wijnen. January 2000.

Mailing Lists

Italicized lists are private.

Topic

List

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Users & Operators

frog@lists.frrouting.org

Announcements

announce@lists.frrouting.org

Security

security@lists.frrouting.org

Technical Steering Committee

tsc@lists.frrouting.org

The Development list is used to discuss and document general issues related to project development and governance. The public Slack instance and weekly technical meetings provide a higher bandwidth channel for discussions. The results of such discussions are reflected in updates, as appropriate, to code (i.e., merges), GitHub issues tracked issues, and for governance or process changes, updates to the Development list and either this file or information posted at FRR.

Bug Reports

For information on reporting bugs, please see Reporting Bugs.