---
name: "dccpclo"
section: "1"
platform: "linux"
package: "ion"
version: "3.2.1+dfsg-1.1"
release: "Debian 9 (Stretch)"
platforms: ["linux"]
url: "https://new.carta.tech/dccpclo"
---

# dccpclo(1)

DCCP-based BP convergence layer output task

## 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** is not a "promiscuous" convergence layer daemon: it can transmit bundles only to the node to which it is connected, so scheme configuration directives that cite this outduct need only provide the protocol name and the outduct name as specified on the command line when **dccpclo** is started.

Note also 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 \<ion-bugs@korgano.eecs.ohiou.edu\>

## SEE ALSO

[*bpadmin*(1)](/bpadmin/1.md), [*bprc*(5)](/bprc/5.md), [*dccpcli*(1)](/dccpcli/1.md)