The NET/ROM protocol relies on, and uses the AX.25 ports you have created.
The NET/ROM protocol rides on top of the AX.25 protocol. To configure NET/ROM
on an AX.25 interface you must configure two files. One file describes the
NET/ROM interfaces, and the other file describes which of the AX.25 ports
will carry NET/ROM. You can configure multiple NET/ROM ports, each with its
own callsign and alias, the same procedure applies for each.
The first is the /etc/ax25/nrports file. This file describes
the NET/ROM ports in much the same way as the /etc/ax25/axports
file describes the AX.25 ports. Each NET/ROM device you wish to create
must have an entry in the /etc/ax25/nrports file. Normally
a Linux machine would have only one NET/ROM device configured that would
use a number of the AX.25 ports defined. In some situations you might
wish a special service such as a BBS to have a separate NET/ROM alias and
so you would create more than one.
This file is formatted as follows:
name callsign alias paclen description |
Where:
- name
is the text name that you wish to refer to the port by.
- callsign
is the callsign that the NET/ROM traffic from this port will use. Note,
this is not that address that users should
connect to to get access to a node style
interface. (The node program is covered later). This callsign/ssid
should be unique and should not appear elsewhere in either of the
/etc/ax25/axports or the
/etc/ax25/nrports files.
- alias
is the NET/ROM alias this port will have assigned to it.
- paclen
is the maximum size of NET/ROM frames transmitted by this port.
- description
is a free text description of the port.
An example would look something like the following:
netrom VK2KTJ-9 LINUX 236 Linux Switch Port |
This example creates a NET/ROM port known to the rest of the NET/ROM network
as `LINUX:VK2KTJ-9'.
This file is used by programs such as the call program.
The second file is the /etc/ax25/nrbroadcast file. This file may
contain a number of entries. There would normally be one entry for each
AX.25 port that you wish to allow NET/ROM traffic on.
This file is formatted as follows:
axport min_obs def_qual worst_qual verbose |
Where:
- axport
is the port name obtained from the
/etc/ax25/axports file. If you do not have an entry in
/etc/ax25/nrbroadcasts for a port then this means that no NET/ROM
routing will occur and any received NET/ROM broadcasts will be ignored for that
port.
- min_obs
is the minimum obselesence value for the port.
- def_qual
is the default quality for the port.
- worst_qual
is the worst quality value for the port, any routes under
this quality will be ignored.
- verbose
is a flag determining whether full NET/ROM routing broadcasts
will occur from this port or only a routing broadcast advertising the node
itself.
An example would look something like the following:
When you have the two configuration files completed you must create
the NET/ROM device in much the same way as you did for the AX.25
devices. This time you use the nrattach
command. The nrattach works in just the same way
as the axattach command except that it creates
NET/ROM network devices called `nr[0-9]'. Again, the
first time you use the nrattach command it
creates the `nr0' device, the second time it
creates the `nr1' network devices etc. To create
the network device for the NET/ROM port we've defined we would use:
This command would start the NET/ROM device (nr0)
named netrom configured with the details specified
in the /etc/ax25/nrports file.
The Linux kernel does all of the NET/ROM protocol and switching, but does not
manage some functions. The NET/ROM daemon manages the NET/ROM routing tables
and generates the NET/ROM routing broadcasts. You start NET/ROM daemon with
the command:
You should soon see the /proc/net/nr_neigh file filling up with
information about your NET/ROM neighbours.
Remember to put the /usr/sbin/netromd command in your
rc files so that it is started automatically each time you reboot.
You may wish to configure static NET/ROM routes for specific hosts.
The nrparms command enables you to do
this. Again, the man page offers a complete
description, but a simple example might be:
# /usr/sbin/nrparms -nodes VK2XLZ-10 + #MINTO 120 5 radio VK2SUT-9 |
This command would set a NET/ROM route to #MINTO:VK2XLZ-10 via a neighbour
VK2SUT-9 on my AX.25 port called `radio'.
You can manually create entries for new neighbours using the nrparms
command as well. For example:
# /usr/sbin/nrparms -routes radio VK2SUT-9 + 120 |
This command would create VK2SUT-9 as a NET/ROM neighbour with a quality
of 120 and this will be locked and will not be deleted automatically.
