QSFP+ breakout cable (40G to 4x10G) on Mellanox MT27520 ConnectX-3 Pro

Hello,

I have a Mellanox MT27520 ConnectX-3 Pro (2x40G ports) with the latest MLNX OFED driver (version 4.6-1.0.1.1 for Debian 9.6) and I wonder if it is possible to attach a QSFP+ breakout cable (40G to 4x10G) on it?

My goal is to connect each of the 10G extremity to different 10Gb/s switches instead of using a regular 40G DAC to a single switch. I already played with multiple VFS on both ports to divide the 40Gb/s bandwidth accordingly but I would really like to use the QSFP+ breakout cable to enjoy physically separated connectivity.

As an example, I have seen that the Intel XL710 can be configured in such a mode (https://forums.intel.com/s/question/0D50P0000490RYESA2/connect-directly-x710-to-xl710-with-qsfp-breakout-cable?language=en_US). Is it possible to achieve the same with Mellanox driver/firmware? I didn’t find any relevant parameters using mlxconfig, here are the configuration options of my card:

Device #1:


Device type: ConnectX3Pro

Device: /dev/mst/mt4103_pci_cr0

Configurations: Next Boot

SRIOV_EN True(1)

NUM_OF_VFS 16

LINK_TYPE_P1 ETH(2)

PHY_TYPE_P1 XFI(2)

XFI_MODE_P1 _10G(0)

FORCE_MODE_P1 False(0)

LINK_TYPE_P2 ETH(2)

PHY_TYPE_P2 XFI(2)

XFI_MODE_P2 _10G(0)

FORCE_MODE_P2 False(0)

LOG_BAR_SIZE 5

BOOT_PKEY_P1 0

BOOT_PKEY_P2 0

BOOT_OPTION_ROM_EN_P1 True(1)

BOOT_VLAN_EN_P1 False(0)

BOOT_RETRY_CNT_P1 0

LEGACY_BOOT_PROTOCOL_P1 PXE(1)

BOOT_VLAN_P1 1

BOOT_OPTION_ROM_EN_P2 True(1)

BOOT_VLAN_EN_P2 False(0)

BOOT_RETRY_CNT_P2 0

LEGACY_BOOT_PROTOCOL_P2 PXE(1)

BOOT_VLAN_P2 1

IP_VER_P1 IPv4(0)

IP_VER_P2 IPv4(0)

CQ_TIMESTAMP True(1)

STEER_FORCE_VLAN False(0)

Thanks.

BR,

Hi Vincent ,

A. Can you please provide the PSID and FW version of the card? You may run the following commands to get this info:

#[mst start]​

#[mst status]​ (To get name of MST device)

#flint -d q

B. P/N of the cable

C. P/N of the switch

Thanks,

Namrata.

Hi Namrata,

Here are the requested informations:

Image type: FS2

FW Version: 2.42.5044

FW Release Date: 21.10.2018

Product Version: 02.42.50.44

Rom Info: version_id=8025 type=CLP

type=UEFI version=14.11.48 cpu=AMD64

type=PXE version=3.4.754

Device ID: 4103

Description: Node Port1 Port2 Sys image

GUIDs: b88303ffff5c0cd0 b88303ffff5c0cd1 b88303ffff5c0cd2 b88303ffff5c0cd3

MACs: b883035c0cd1 b883035c0cd2

VSD:

PSID: HP_1370110017

Thanks,

Vincent.

Hi Vincent,

Unfortunately, our Mellanox adapters do not have the capability to split the port into 2 or 4 new physical ports.

Many thanks,

~Mellanox Technical Support