If using IOS, NX-OS or IOS-XR network operating system, the debug routine works simply, like in shown example below. Exactly 2 commands are needed to use interactive protocol debugging while being in need of troubleshoot in some situation:

configure terminal
 logging console
end

Enable specific IOS protocol debugging option:

terminal monitor
debug ip ospf adj

The tools are integrated into the environement.

Using FRRouting, the routing debugging routine will not work exactly the same way. vtysh has no option to interactive write protocol debug to the vtysh prompt. Also the terminal monitor is missing from vtysh - the command does exist on telnet.

But redirect-ing the '''debugging output''' to the local syslog instead works.

Debug FRRouting in a interactive manner much like it is known from the Cisco CLI output. Without the need of editing the system node files.

This article is a simple demonstration using the RIPng, OSPF6 and IS-IS routing protocol debugging, to show the different debug options in action.

Following setup steps are for the FRR's ''vtysh'' shell. Enable the routing protocol debugging to be redirected the nodes system syslog:

conf
 log syslog debugging
end
wr

Enable the routing protocol debugging in the FRR vtysh. First example below is showing a RIPNG routing protocol debug.

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The Babel routing protocol. Babel is a routing protocol designed for wireless and wired networks. Babel is a distance-vector routing protocol. Babel converges quickly compared to other distance-vector routing protocols. Babel does NOT support BFD, at least not using FRRouting. Babel uses multiple metrics, to calculate the path to a route. Babel could be used in wired networks but always having in mind that it was designed primarily for wireless networks. In this netlab it is shown how to setup a basic babel wired topology. It is using a FRR 8.2.2 running on a alpine linux appliance. See Building 64bit alpine linux GNS3 FRRouting appliance. This netlab is running using the Graphical Network Simulator - GNS3.

Topology

This netlab is using a triangle design. It is using IPv6 only.

Triangle network topology and addressing:

            lo                                          lo
    2001:db8:1111::/128                         2001:db8:2222::/128
        +-------+                                   +-------+
        |       | eth0                         eth0 |       |
        |  FRR1 |-----------------------------------|  FRR2 |
        |       |                                   |       |
        +-------+                                   +-------+
       eth2 |                                           | eth1
            |                                           |
            |                                           |
            |                                           |
            |                                           |
            |                                           |
            |                 +-------+                 |
            |                 |       |                 |
            +-----------------|  FRR3 |-----------------+
                         eth2 |       | eth1
                              +-------+
                                  lo
                          2001:db8:3333::/128

This netlab uses wired connections to cover the basic information about the Babel routing protocol, and its current implementation status in FRRouting.

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