---
name: "rxe_cfg"
section: "8"
platform: "linux"
package: "rdma-core"
version: "22.1-1"
release: "Debian 10 (Buster)"
platforms: ["linux"]
url: "https://new.carta.tech/rxe_cfg"
---

# rxe\_cfg(8)

rxe configuration tool for RXE (Soft RoCE)

## NAME

rxe\_cfg - rxe configuration tool for RXE (Soft RoCE)

## SYNOPSIS

**rxe\_cfg \[status\]**\
 **rxe\_cfg start** \[**-p** *proto*\]\
 **rxe\_cfg stop**\
 **rxe\_cfg persistent**\
 **rxe\_cfg add** \[**-n**\] *ethN*\
 **rxe\_cfg remove** \[**-n**\] *ethN*\|*rxeN*\
 **rxe\_cfg crc enable**\|**disable**\
 **rxe\_cfg** **mtu** \[**-f**\] \[*rxeN*\] *mtu\_size*\

## DESCRIPTION

rxe\_cfg is the configuration tool for the RXE software implementation of the RoCE protocol.

The RXE kernel modules are loaded, configured, reconfigured and unloaded via the various rxe\_cfg command options, documented below.

## PARAMETERS

- *proto*

  Ethertype field. Default value is 0x8915. This value must be changed to use RXE on Mellanox ConnectX adapters.

- *ethN*

  Network device name as listed in /sys/class/net. Only Ethernet devices are supported; ie. eth0 or eth0.1234 for VLANs.

- *rxeN*

  RXE device name as listed in /sys/class/infiniband/. Examples are rxe0 or rxe1.

- *mtu\_size*

  RoCE mtu. For RoCE the mtu represents the payload excluding headers and has the possible values: 256, 512, 1024, 2048 and 4096.

## COMMANDS

- \[**status**\]

  The **status** command prints a table of information on available Ethernet devices and configured RXE instances.  The status display is the default if no options are provided.

- **start** \[**-p** *proto*\]

  The **start** command loads the RXE modules and configures any persistent instances.  If the **-p** *proto* option is included, the RXE modules will be configured to use Ethertype = *proto*.  (This allows testing RXE on devices, like Mellanox ConnectX, that already support the default RoCE Ethertype in hardware.)

- **stop**

  The **stop** command unconfigures all RXE instances and attempts to unload the kernel modules.

- **persistent**

  The **persistent** command prints the list of Ethernet devices for which a RXE instance is persistently configured.

- **add** \[**-n**\] *ethN*

  The **add** command will configure a RXE instance on Ethernet device *ethN* (e.g. eth0).  The RXE modules must have already been loaded via **rxe\_cfg start**.

  The default behavior is to add *ethN* to a file of persistent configurations and the same RXE device will be configured the next time that **rxe\_cfg start** is run.  If the **-n** option is included the device is not added to the persistence file.

- **remove** \[**-n**\] *ethN*\|*rxeN*

  The **remove** command will remove the specified RXE instance.  The parameter must match a currently active ethN or rxeN name.

  If the **-n** option is included the RXE device will be removed but not removed from the persistent state. So it will be recreated the next time that **rxe\_cfg start** is run.

- **mtu** \[**-f**\] \[*rxeN*\] *mtu\_size*

  The **mtu** command will set the RoCE MTU of all RXE devices to *mtu\_size*, provided that the underlying Ethernet MTU is sufficiently large.  If the Ethernet MTU is not large enough, RXE will use the largest MTU that fits; the driver remembers the requested RoCE MTU and will increase the currently active MTU if the Ethernet MTU is later changed up to the requested MTU.

  If the **-f** option is included the underlying Ethernet MTUs will be increased if necessary to the minimum size to accommodate a RoCE MTU of *size*.

  If a *rxeN* instance is specified then only that instance will be affected by the command.

- **crc** **enable**\|**disable**

  The **crc** command will enable or disable RoCE ICRC calculation.  Valid ICRCs are be required to communicate hardware RoCE NICs, but when a RXE instance is communicating with another RXE instance the performance will be better with the CRC disabled.

  This option is global to all RXE instances.

## FILES

- **\[PREFIX\]/etc/rxe.conf**

  RXE configuration file. Contains the list of persistent RXE instances.  All persistent RXE instances can be removed by deleting this file (note this will take effect on the next "rxe\_cfg start" -- to remove actively configured instances, you must "rxe\_cfg stop").

## SEE ALSO

[**rxe**(7)](/rxe/7.md),

## AUTHORS

Written by John Groves, Frank Zago and Bob Pearson at System Fabric Works.