---
name: "bus"
section: "8"
platform: "linux"
package: "linux-atm"
version: "2.5.2-9"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/les"
---

# bus(8)

ATM LAN Emulation service demons

Part of [les(8)](/les/8.md).

## NAME

les, bus - ATM LAN Emulation service demons

## SYNOPSIS

**les** \[**-d *module***\] \[**-m *module***\] \[**-f *configuration\_file***\]

**bus** \[**-d *module***\] \[**-m *module***\] \[**-f *configuration\_file***\]

## DESCRIPTION

LE Service consists of three components: LAN Emulation Configuration  Server (**[lecs(8)](/lecs/8.md)**), LAN Emulation Server (**les**) and Broadcast  and Unknown Server (**bus**).

**Les** performs the control coordination function for the emulated LAN.  LE clients register MAC addresses and/or route descriptors they represent  to **les**, and later query it when they want to resolve MAC addresses/route  descriptors into ATM addresses. Other LE control messages which are to be  distributed to every client in ELAN are also sent to **les**. **Les** forwards these messages using Control Distribute VCC which it has set up  to every client in ELAN.

**Bus** handles data sent by clients to broadcast and multicast  MAC addresses and some of the data directed to unicast addresses. LE  Client has a possibility to send data directed to some unicast address  to the **bus** before target's ATM address has been resolved and the Data  Direct VCC has been established.

Configuration file example for **les** and **bus**:

```
[main]
memdebug=True
debug=True
[load]
#memdebug=True
#debug=True
[conn]
debug=True
#S1, LE Server's ATM address
#S1=:47:00:23:00:00:00:03:00:00:01:00:02:01:00:20:ea:00:05:aa:00
S1=:47:00:23:00:00:00:03:03:00:01:00:02:01:00:20:ea:00:0a:e9:01
#S2, LAN Type
S2="802.3"
#S3, Maximum Frame Size
S3=1516
#S4, Join Timeout, s
S4=15
#S5, Maximum Frame Age, s
S5=6
#S6, BUS Atm address
S6=:47:00:23:00:00:00:03:03:00:01:00:02:01:00:20:ea:00:0a:e9:02 #viulu
#S6=0,0,170
#ELANNAME="asdf"
```

The configuration file contains each modules name in brackets followed by  variable definitions for that module. The definitions are of form  *variable=value,* where value can be either an integer, a truth value (True/False), a  string enclosed in double quotes  *("string")* or an ATM address in hexadecimal format. Variables that can be set are  the debug/memdebug for each module and variables S1-S6 as defined in  LE specification.

```
S1=Address of the LES. This address is used in ATM
   signalling.
S2=Type of the emulated LAN. Valid values is "802.3".
S3=Maximum frame size. Valid value is 1516.
S4=Join Timeout. Time in seconds which LES waits for
   LE_JOIN_REQUEST before tearing down a connection.
S5=Maximum frame Age. Currently not used.
S6=Address of the BUS. This address is used in ATM signalling.
ELANNAME= Name of the emulated LAN
```

**SIGHUP** causes restart of the server. All resources are  released and server is started. **SIGUSR1** causes the server to dump its internal state. **SIGUSR2** shuts down the server (hopefully) gracefully.

## OPTIONS

- Set debugging messages on for a module. "All" sets debugging

  - **-d** *module*

  on for all modules.

- **-m** *module*

  Set memory debugging messages on for a module. "All" sets debugging on for all modules.

- **-f** *configuration\_file*

  Use the specified configuration file instead of **.lanevars**.

## FILES

- **.lanevars**

  configuration file

## BUGS

Servers don't establish point-to-multipoint connections to LE clients as the specification states, which means that some LE clients won't work with these servers.

Supports only IEEE 802.3 / Ethernet type of ELANs.

This manual page is confusing.

## AUTHOR

Marko Kiiskila, TUT \<carnil@cs.tut.fi\>

## SEE ALSO

[lecs(8)](/lecs/8.md), [atmsigd(8)](/atmsigd/8.md), [zeppelin(8)](/zeppelin/8.md)