Connect via pdn (packet.net)¶

pdn is the packet.net node. DAPPS runs on it as an app: pdn installs it, starts and supervises it, gives it a callsign, and puts its dashboard on a tile in pdn's control panel. DAPPS talks to the node over RHPv2.

Run DAPPS as a pdn app¶

Check the version first. pdn's built-in app catalogue installs DAPPS 0.34.3 (as of pdn node-v0.55.2). That's older than DAPPS 0.40, which brought the exchange between nodes, and older than the fix that keeps DAPPS from losing the other node's greeting on pdn (in the release after 0.42.0). Until the catalogue is updated, put a current DAPPS in place by hand (step 2 below), or run DAPPS on its own.

1. Turn on pdn's RHPv2 server. It's off by default. Add this to pdn's config (the control panel's Config screen, or packetnet config export / import):

rhp:
  enabled: true

That listens on 127.0.0.1:9000, which is all DAPPS needs when it runs on the node.

2. Install DAPPS. From the control panel's Apps screen you get the catalogue's 0.34.3. For a current release, put its pdn package in /var/lib/packetnet/apps/dapps/ yourself (use dapps-linux-x64 on a PC, dapps-linux-arm on 32-bit Raspberry Pi OS); this also replaces a catalogue install:

sudo -u packetnet mkdir -p /var/lib/packetnet/apps/dapps
cd /var/lib/packetnet/apps/dapps
sudo -u packetnet curl -fsSLO https://github.com/packet-net/dapps/releases/latest/download/pdn-app.yaml
sudo -u packetnet curl -fsSL -o dapps https://github.com/packet-net/dapps/releases/latest/download/dapps-linux-arm64
sudo chmod 755 dapps

Then enable it on the Apps screen. pdn gives it your node's callsign with a free SSID. To choose the callsign yourself, add it to pdn's apps: block:

apps:
  - id: dapps
    enabled: true
    callsign: M0LTE-7

3. Open DAPPS from its tile, and add your neighbours on its dashboard.

Run DAPPS on its own against pdn¶

If you installed DAPPS separately (say from the apt repo), point it at pdn in the /Setup wizard or Edit configuration:

Field	Value
Node bearer	RHPv2
Node host	pdn's host (`localhost` if it's the same machine)
RHPv2 port	`9000`, or whatever pdn's `rhp.port` says
Default bearer port	`0`, for pdn's first port (see below)

If DAPPS is on another machine, pdn's rhp.bind has to be an address that machine can reach. RHPv2 has no encryption, so keep it on a network you trust. If you set requireAuth: true, give DAPPS a pdn username and password as its RHPv2 user and password.

Which port DAPPS uses¶

DAPPS asks pdn for a port by number, one more than its bearer port: bearer port 0 is pdn's first port, 1 its second, in the order your config lists them. pdn node-v0.56.0 and later take a port's number as well as its name, so the port can have any name.

Older pdn releases only take a port's name (packet.net#841). On those, name the port DAPPS uses 1, or 2 if you set DAPPS's bearer port to 1, and so on:

ports:
  - id: "1"
    transport:
      kind: kiss-tcp
      host: 127.0.0.1
      port: 8001

Radio port settings¶

As with BPQ (Tune), your radio port's timers matter more than anything in DAPPS. These are pdn's names for the settings we tested on a simulated 2 m FM channel:

pdn setting	AFSK 1200	QPSK 3600	BPQ name
`ax25.t1Ms`	7000	4000	`FRACK`
`ax25.t2Ms`	1000	1000	`RESPTIME` (pdn's default is 3000, which holds every acknowledgement back 3 s)
`ax25.windowSize`	4	7	`MAXFRAME`
`ax25.n1`	120	236	`PACLEN`
`kiss.persistence`, `kiss.slotTime`	64, 10	64, 10	`PERSIST`, `SLOTTIME`
`kiss.txDelay`	As short as your radios allow (units of 10 ms)		`TXDELAY`

pdn always sends your TNC a TX tail, 0 unless you set kiss.txTail. A software modem such as Dire Wolf usually wants one: 10 (100 ms) is Dire Wolf's own default.

If the neighbour is a BPQ node, set link: dial: v20 on that port, as pdn's own docs say: many BPQ builds ignore the newer connect pdn tries first.

Good to know¶

When both nodes call each other at once, pdn joins the two calls into one link. With pdn node-v0.59.0 or later, pdn tells DAPPS when that happens (from the DAPPS release after 0.42.0), so it carries straight on and a crossed call finishes about 10 s sooner. With older pdn each end waits 10 s for a greeting first; on node-v0.57.0 and v0.58.0 carrying straight on sometimes costs a redial, so upgrade pdn. Nothing is lost either way.
Linking pdn to a BPQ node over AXIP: one MAP line in BPQ for pdn's address, for the DAPPS callsign, is all DAPPS needs. With a second line for the same address (the node's callsign as well), BPQ sends every frame twice. pdn node-v0.56.0 and later cope with that; on older pdn the link never comes up (packet.net#842).