The DoDWAN platform
DoDWAN Apps for netbooks
Starting DoDWAN Apps
DoDWAN Apps Overview
DoDWAN Apps for smartphones
Hints and tips
Running DoDWAN programs
Using the DoDWAN API
Reference Java API
|The behaviour of DoDWAN is determined by a set of Java properties that are defined in DoDWAN’s configuration files (dodwan.defaults and/or dodwan.conf). These properties can if needed be overriden in the command line when launching DoDWAN, using options of the form -Dproperty=value.
In the default configuration file dodwan.defaults, a special property (immutable) contains a comma-separated list of properties whose definition cannot be overriden in dodwan.conf or in the command line.
The following properties are recognized by DoDWAN:
- dodwan.interface_address (default: ::)
Address of the local interface used for DTN communication. This can be either an IPv4 or IPv6 address. Attempts to join the multicast group (whose address is specified in dodwan.remote_address) will be made on this interface, or on the system-default interface if none is specified (the system-default wildcard address is 0.0.0.0 in IPv4, and :: in IPv6).
- dodwan.local_address (default: ::)
Address of the local interface used for DTN communication. This can be either an IPv4 or IPv6 address. The default wildcard address can normally be used here. That’s 0.0.0.0 in IPv4, and :: in IPv6.
- dodwan.remote_address (default: FF02:0:0:0:236:1:2:3)
Address of the multicast group used for DTN communication (for example 188.8.131.52 in IPv4, or FF02:0:0:0:236:1:2:3 in IPv6)
- dodwan.dtn_port (default: 8500)
UDP port used for DTN communication
- dodwan.console_port (default: 8500) TCP port used by the DoDWAN console for telnet-like control. This is typically the same port number as that of the UDP communication port (specified in dodwan.dtn_port). Note that the DoDWAN console actually uses two TCP ports (that is, port numbers N and N+1, where N=dodwan.console_port), the first port being reserved for interactive use, and the second port for one-shot commands.
- dodwan.announce_period (default: 15)
Period (in seconds) of the announcement broadcast by DoDWAN.
- dodwan.announce_latency (default: 35)
Latency (in seconds) of an announcement. A neighbor host perceived by DoDWAN is considered as missing when the last announcement received from this host is older than the announce_latency value. The latency should always be greater than the period.
- dodwan.fragmentation_threshold (default: 50000)
Fragmentation threshold (in bytes) for the segmentation and reassembly of large messages (that cannot fit in a single UDP datagram, typically). The value specified must be an integer, optionally followed by a quantifier (i.e. b or B, k or kB, M or MB).
- dodwan.inter_message_delay (default: 10)
Inter-message delay (in milli-seconds). This argument is used by DoDWAN when multiple messages (typically, fragments of a large message) must be broadcast in a row on the multicast channel.
- dodwan.max_payload_size (default: 0)
Maximum payload size (in bytes). Messages whose payload is larger than the specified size cannot be processed by DoDWAN, and are therefore discarded. If the value of this parameter is set to 0 (zero), then it means that there is actually no limit to the payload size (use this possibility with caution!). The value specified must be an integer, optionally followed by a quantifier (i.e. B, k or kB, M or MB).
- dodwan.cache_capacity (default: 0)
Cache capacity (in bytes). DoDWAN’s cache is maintained in the filesystem, and the payloads of messages are stored in a particular directory. This argument sets a limit on the total size of this directory. (Note that the size of message descriptors is not accounted for.) If the value of this parameter is set to 0, then it means that there is actually no limit to the cache capacity (use this possibility with caution!). The value specified must be an integer, optionally followed by a quantifier (i.e. B, k or kB, M or MB).
- dodwan.start_online (default: false)
Boolean connectivity status (online/offline) of DoDWAN at launch time. Specifies whether DoDWAN should switch online or stay offline after its code has been loaded in the JVM.
- dodwan.transaction_timeout (default: 15)
Specifies how long a transaction between two neighbour hosts can be idle before one of the hosts considers sending a new offer to its neighbour. This value is expressed in seconds. A resonable value for this parameter should be chosen in the interval between half the announcement period and the announcement period.