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NAME

dccpclo - DCCP-based BP convergence layer output task

SYNOPSIS

dccpclo remote_hostname[:remote_port_nbr]

DESCRIPTION

dccpclo is a background "daemon" task that connects to a remote node's DCCP socket at remote_hostname and remote_port_nbr. It then begins extracting bundles from the queues of bundles ready for transmission via DCCP to this remote bundle protocol agent and transmitting those bundles as DCCP datagrams to the remote host.

If not specified, remote_port_nbr defaults to 4556.

Note that dccpclo has no fragmentation support at all. Therefore, the largest bundle that can be sent via this convergence layer is limited to just under the link's MTU (typically 1500 bytes).

dccpclo is spawned automatically by bpadmin in response to the 's' (START) command that starts operation of the Bundle Protocol, and it is terminated by bpadmin in response to an 'x' (STOP) command. dccpclo can also be spawned and terminated in response to START and STOP commands that pertain specifically to the DCCP convergence layer protocol.

EXIT STATUS

  • "0"

    dccpclo terminated normally, for reasons noted in the ion.log file. If this termination was not commanded, investigate and solve the problem identified in the log file and use bpadmin to restart dccpclo.

  • "1"

    dccpclo terminated abnormally, for reasons noted in the ion.log file. Investigate and solve the problem identified in the log file, then use bpadmin to restart dccpclo.

FILES

No configuration files are needed.

ENVIRONMENT

No environment variables apply.

DIAGNOSTICS

The following diagnostics may be issued to the ion.log log file:

  • dccpclo can't attach to BP.

    bpadmin has not yet initialized Bundle Protocol operations.

  • No memory for DCCP buffer in dccpclo.

    ION system error. Check errtext, correct problem, and restart dccpclo.

  • No such dccp duct.

    No DCCP outduct matching local_hostname and local_port_nbr has been added to the BP database. Use bpadmin to stop the DCCP convergence-layer protocol, add the outduct, and then restart dccpclo.

  • CLO task is already started for this duct.

    Redundant initiation of dccpclo.

  • dccpclo can't get IP address for host.

    Operating system error. Check errtext, correct problem, and restart dccpclo.

  • dccpclo can't create thread.

    Operating system error. Check errtext, correct problem, and restart dccpclo.

  • CLO can't open DCCP socket. This probably means DCCP is not supported on your system.

    Operating system error. This probably means that you are not using an operating system that supports DCCP. Make sure that you are using a current Linux kernel and that the DCCP modules are being compiled. Check errtext, correct problem, and restart dccpclo.

  • CLO can't initialize socket.

    Operating system error. Check errtext, correct problem, and restart dccpclo.

  • CLO send() error on socket.

    Operating system error. Check errtext, correct problem, and restart dccpclo.

  • Bundle is too big for DCCP CLO.

    Configuration error: bundles that are too large for DCCP transmission (i.e., larger than the MTU of the link or 65535 bytes--whichever is smaller) are being enqueued for dccpclo. Change routing or use smaller bundles.

BUGS

Report bugs to <https://github.com/nasa-jpl/ION-DTN/issues>

SEE ALSO

bpadmin(1), bprc(5), dccpcli(1)