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

# udplso(1)

UDP-based LTP link service output task

## NAME

udplso - UDP-based LTP link service output task

## SYNOPSIS

**udplso** {*remote\_engine\_hostname* \| @}\[:*remote\_port\_nbr*\] \[*txbps*\] *remote\_engine\_nbr*

## DESCRIPTION

**udplso** is a background "daemon" task that extracts LTP segments from the queue of segments bound for the indicated remote LTP engine, encapsulates them in UDP datagrams, and sends those datagrams to the indicated UDP port on the indicated host.  If not specified, port number defaults to 1113.

UDP congestion can be controlled by setting udplso's rate of UDP datagram transmission *txbps* (transmission rate in bits per second) to the value that is supported by the underlying network.

Each "span" of LTP data interchange between the local LTP engine and a neighboring LTP engine requires its own link service output task, such as **udplso**.  All link service output tasks are spawned automatically by **ltpadmin** in response to the 's' command that starts operation of the LTP protocol, and they are all terminated by **ltpadmin** in response to an 'x' (STOP) command.

## EXIT STATUS

- "0"

  **udplso** 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 **ltpadmin** to restart **udplso**.

- "1"

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

## FILES

No configuration files are needed.

## ENVIRONMENT

No environment variables apply.

## DIAGNOSTICS

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

- udplso can't initialize LTP.

  **ltpadmin** has not yet initialized LTP protocol operations.

- No such engine in database.

  *remote\_engine\_nbr* is invalid, or the applicable span has not yet been added to the LTP database by **ltpadmin**.

- LSO task is already started for this engine.

  Redundant initiation of **udplso**.

- LSO can't open UDP socket

  Operating system error.  Check errtext, correct problem, and restart **udplso**.

- LSO can't connect UDP socket

  Operating system error.  Check errtext, correct problem, and restart **udplso**.

- Segment is too big for UDP LSO.

  Configuration error: segments that are too large for UDP transmission (i.e., larger than 65535 bytes) are being enqueued for **udplso**.  Use **ltpadmin** to change maximum segment size for this span.

## BUGS

Report bugs to \<ion-bugs@korgano.eecs.ohiou.edu\>

## SEE ALSO

[*ltpadmin*(1)](/ltpadmin/1.md), [*ltpmeter*(1)](/ltpmeter/1.md), [*udplsi*(1)](/udplsi/1.md), [*owltsim*(1)](/owltsim/1.md)