babeld

Loop-avoiding distance-vector routing protocol daemon.

TLDR

Start Babel routing daemon

$ babeld [eth0]

Start with configuration file

$ babeld -c [/etc/babeld.conf] [eth0]

Run in foreground

$ babeld -d [1] [eth0]

Multiple interfaces

$ babeld [eth0] [eth1] [wlan0]

babeld is a loop-avoiding distance-vector routing protocol daemon. Babel is designed for IPv6 and IPv4 networks, particularly wireless mesh networks, providing fast convergence and low overhead.The daemon implements the Babel routing protocol (RFC 8966) and is suitable for small to medium-sized networks.

PARAMETERS

-c file

Configuration file (repeatable).

-C statement

Provide configuration via command line.

-d level

Debug level (0-3).

-D

Daemonize at startup.

-L file

Log file location.

-I file

PID file location.

-S file

State file for preserving long-term information between invocations.

-h seconds

Hello packet interval for wireless interfaces (default: 4s).

-H seconds

Hello packet interval for wired interfaces (default: 4s).

-m address

Link-local multicast address (default: ff02:0:0:0:0:0:1:6).

-p port

UDP port number (default: 6696).

-k priority

Kernel route installation priority (default: 0).

-g port|path

Enable read-only configuration server.

-G port|path

Enable read-write configuration server.

-t table

Kernel routing table for route insertion.

-w

Treat all interfaces as wireless by default.

-s

Disable split-horizon on wired interfaces.

-r

Use random router-id instead of deriving from MAC address.

-l

Use IFF_RUNNING to detect interface availability.

CONFIGURATION

/etc/babeld.conf

Main configuration file for interface settings, filters, and redistribution rules.

FEATURES

- Loop-free routing- Fast convergence- IPv4 and IPv6 support- Link quality sensing- Multiple routing metrics- Extensible through configuration

CAVEATS

Requires proper network configuration. All nodes must run compatible Babel implementation. Wireless networks need link quality extensions. Not suitable for large-scale networks (use BGP/OSPF). Configuration errors can cause routing loops.

HISTORY

Babel was designed by Juliusz Chroboczek around 2008 as an improved distance-vector protocol for mesh networks, later standardized as RFC 6126 and updated to RFC 8966.