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- OSI layer 2 (data link layer) protocol. Technically, it occupies layers 1-3.
- Same layer as BATMAN-Advanced.
- Used for packet radio by hams.
- Can transport network layer protocols, including IP.
- Not designed to support switching, though routers can probably be set up to handle it.
- Support in the Linux kernel.
- v2.6.x: ax25.ko
- Commonly used with three different communication specs:
- Bell 103 tones @ 300bps
- Bell 202 tones @ 1200bps
- G3RUH DFSK @ 9600bps
- These speeds are hard limits.
- KISS encapsulates frames such that they can be send to a TNC for transmission. Derived from SLIP.
- KISS is a serial protocol. Thus, multiple serial channels are required for multiple transceivers.
- Other protocols fulfill the same function.
- Either half or full duplex modes.
- Three components
- Kernel module
- Configuration utilities
- Utility software
- Each AX.25 network device ("port") must be configured with a unique callsign/SSID. Hostnames are probably not a good idea.
- We would be using soundmodem on top of AX.25.
Configuring AX.25 network interface:
ifconfig sm0 hw ax25 <callsign> up
Create an entry in /etc/ax25/axports for the network interface: sm0 <callsign> <speed in bps> <maximum packet length> <AX.25 window parameter (K)> <description of interface>
Once this is done, you can treat it like any other network interface:
ifconfig sm0 192.168.1.1 netmask 255.255.255.0 route add -net 192.168.1.0 netmask 255.255.255.0 sm0 route add default sm0