For a NET/ROM based network to operate correctly, a periodic broadcast of routing information needs to occur. Typically this occurs once every hour on every port which is expected to carry NET/ROM traffic. The purpose of netromd is to send and receive NET/ROM routing broadcasts. To operate correctly a set of parameters that corresponds to each AX.25 port needs to be passed to the program. This information is encoded in a configuration file, by default which is /etc/ax25/nrbroadcast with each line representing one port, see the manual page for nrbroadcast(5).
To cut down the length of these routing broadcasts, only the information about the highest quality neighbour for a particular node is transmitted. The transmission is also limited to those node that have a certain minimum value in their obsolesence count, this value is decremented every time a routing broadcast is transmitted, and is refreshed by receiving a routing broadcast which contains that particular node.
The value of the default quality is traditionally assigned a value that represents the quality of the radio links on that port. A higher number representing better radio links with 255 (the maximum) reserved for wire connections. The practise in the UK is to set the default quality to a low value, typically 10, and manually set up the trusted neighbouring nodes in the neighbour list manually. The worst quality for auto-updates value is a way to filter out low quality (ie distant) nodes.
The verbose flag may be either 0 or 1, representing no and yes. By specifying no, the program will only generate a routing message containing information about the node on which it is running, by specifying the yes option, all the information in the nodes routing tables will be transmitted. The quality advertised for the other node callsigns on this machine may be set using the -q option.
Between each transmission netromd pauses for five seconds (default) in order to avoid flooding the channels that it must broadcast on. The value of this delay is settable with the -p option.