Mellanox ConnectX-3 on ebay look strange

hmartin

Active Member
Sep 20, 2017
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No, they said for that quantity, if you want the adapter, buy the auction with the Mellanox card and shuck the adapter yourself.

The adapter is passive, so I don't think it would be beyond the realm of someone to design their own. The OCP mezzanine pinout is public, as is the PCIe pinout. I don't do PCB design but someone could probably OSH Park an adapter for less than the $22 this seller is charging for the adapter + Mellanox.

I would definitely be down for 5 adapters, if anyone with PCB experience is looking for a commission ;)
 
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JustinClift

Member
Oct 5, 2014
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Looking at the adapter photo's by @matthew5025:

https://forums.servethehome.com/index.php?attachments/image-sfp-jpg.12177/

https://forums.servethehome.com/index.php?attachments/image-sfp-4-jpg.12180/

...some things stand out about the PCB design:
  • It has places allocated for resisters, but they appear to be unpopulated.
  • Not sure if it's just a two layer pcb (back and front) only. The traces + via's (the small round holes) seem to just be connecting both sides of the PCIe traces through to the OCP connector in fairly simple fashion.
  • If that's really the case, it should be reasonably straight forward to map those out, and make a new pcb.
Not sure if it's useful, but I've been getting an old X-carve (hobby level CNC machine) up and running at a local Maker space. Got it responding to movements ok last week, and AFAIK the only thing it needs next is to be calibrated (not hard).

That's pretty much the exact thing needed for doing initial PCB prototyping, prior to getting a batch made.

Am kind of iffy on whether it's something I want to do though. It'd be my first PCB creating experience, so probably wouldn't be a bad intro... :)

Hmmm, I'll ask the Makerspace people if anyone there has PCB creation experience. If they do, that'd be really useful. :)
 

int0x2e

Member
Dec 9, 2015
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Hi - "head on block time, so swing away" - as I'd only ever heard of Mellanox ConnectX-3, an hour ago, and my money is burning a hole in my pocket :)....

has anyone tested these, are they going to achieve .... "it can run 10 Gigabit Ethernet, 40Gb Ethernet, or InfiniBand at up to 56Gb per second from the same card"?

would it be wise to spend more?

Regards
These are only 10G. There are other ConnectX-3 / CX3Pro based cards that support 40/56Gb. Strongly advise you read a little more before you spend your money (though these aren't too expensive).
 

JustinClift

Member
Oct 5, 2014
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Yeah, it's one of those things that, if you're coming from a 1GbE background and haven't really used 10/40/etc Gb/s network gear before, you're definitely best off starting small and getting the hang of things. Infiniband is a substantially different stack compared to Ethernet / TCP/IP. Not all software even works with Infiniband, though there are workarounds (IPoIB) which can go pretty far on some OS's.

If there's a general scenario you have in mind (eg you're wanting to set up XYZ network structure for project ABC), then maybe share the details of that and we can advise? :)
 
Last edited:

Floggedhorse

New Member
Nov 18, 2019
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Many many thanks.

Will take your advise and start small, especially as I'm peer to peering between windows and Linux

Many thanks .... my money survived the night

Think I'll spend a tad more and purchase something more standard such as this way more availability of drivers and hopefully easier curve

Again thank you
 

JustinClift

Member
Oct 5, 2014
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With those, notice that specific Ebay item comes with the short (half height) bracket. If you're thinking to put it in a standard ATX mini tower case or similar, although the card will fit, the bracket wont. ;)
 

JustinClift

Member
Oct 5, 2014
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As an additional thought, if you're just after a straight connection between two boxes (eg server to a workstation), then something like this would be fairly simple:

Mellanox MCX311A-XCAT CX311A ConnectX-3 EN 10G Ethernet 10GbE SFP+ PCI-E NIC | eBay

Note, I don't know that seller at all, etc. It's just the first example on Ebay showing a preselected bundle of two cards + matching cable.

That's only a 10GbE setup, but depending on what your needs are, it could be fine. Going for something higher speed, like the cards you pointed to, would work too but be a bit more expensive again. Still not that expensive though. :)
 

Mcdull

New Member
Nov 20, 2019
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As an additional thought, if you're just after a straight connection between two boxes (eg server to a workstation), then something like this would be fairly simple:

Mellanox MCX311A-XCAT CX311A ConnectX-3 EN 10G Ethernet 10GbE SFP+ PCI-E NIC | eBay

Note, I don't know that seller at all, etc. It's just the first example on Ebay showing a preselected bundle of two cards + matching cable.
I've been watching this for a while, as I'm not sure $30 for a card is good price?
It's not bundle of two cards, the picture is just to show low and high profile bracket.
It said specifically purchase is for one card only in the description
 

JustinClift

Member
Oct 5, 2014
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It's not bundle of two cards
Sorry, my bad. Sometimes people have bundles available of 2 x [some card] + 1 x [correct cable to join them]. Makes it easy for new people who just want a solution that works easily. Thought it was one of those.
 

JanCerny

Member
Nov 25, 2017
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Czech Republic
Card details:
Mellanox ConnectX-3 MCX341 SFP+10Gigabit Ethernet RMDA/RoCE | eBay
LAN1-sth.jpg LAN2-sth.jpg

Code:
PS C:\WINDOWS\system32> Get-NetAdapter | sort Name | ft Name, InterfaceDescription, LinkSpeed -AutoSize             
Name                          InterfaceDescription                        LinkSpeed
----                          --------------------                        ---------
Ethernet                      Intel(R) I350 Gigabit Network Connection    0 bps
Ethernet 2                    Intel(R) I350 Gigabit Network Connection #2 1 Gbps
Ethernet 3                    Mellanox ConnectX-3 Ethernet Adapter        0 bps
VMware Network Adapter VMnet1 VMware Virtual Ethernet Adapter for VMnet1  100 Mbps
VMware Network Adapter VMnet8 VMware Virtual Ethernet Adapter for VMnet8  100 Mbps


PS C:\WINDOWS\system32> Get-NetAdapterSriov | sort name | ft Name, InterfaceDescription, SriovSupport, NumVFs -AutoSize
Name       InterfaceDescription                   SriovSupport NumVFs
----       --------------------                   ------------ ------
Ethernet 3 Mellanox ConnectX-3 Ethernet Adapter NoIoMmuSupport    128


PS C:\WINDOWS\system32> Get-MlnxPCIDeviceSriovSetting                                                               

Caption          : MLNX_PCIDeviceSriovSettingData 'Mellanox ConnectX-3 VPI (MT04099) Network Adapter'
Description      : Mellanox ConnectX-3 VPI (MT04099) Network Adapter
ElementName      : HCA 0
InstanceID       : PCI\VEN_15B3&DEV_1003&SUBSYS_007515B3&REV_00\F452140300D3A0F400
Name             : HCA 0
Source           : 3
SystemName       : WORKSTATION
SriovPort1NumVFs : 0
SriovPort2NumVFs : 0
SriovPortMode    : 2
PSComputerName   :



PS C:\WINDOWS\system32> mlxfwmanager.exe --query                                                                        Querying Mellanox devices firmware ...

Device #1:
----------

  Device Type:      ConnectX3
  Part Number:      MCX341A-XCC_Ax
  Description:      ConnectX-3 EN NIC for OCP;10GbE;single-port SFP+;PCIe3.0 x8;IPMI disabled;R6
  PSID:             MT_1270110023
  PCI Device Name:  mt4099_pci_cr0
  Port1 MAC:        f45214XXXXXX
  Port2 MAC:        f45214XXXXXX
  Versions:         Current        Available
     FW             2.42.5000      N/A
     PXE            3.4.0752       N/A
     UEFI           14.11.0045     N/A

  Status:           No matching image found
 

lowfat

Active Member
Nov 25, 2016
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Anyone using one of these? Buying one is significantly cheaper than buying a QSFP to SFP+ adapter for my current CX-3s.

Kind of worried about heat tho as the heatsink is sandwiched between the PCB and the PCIe adapter.

 

BeTeP

Well-Known Member
Mar 23, 2019
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lowfat

Active Member
Nov 25, 2016
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MAM1Q00A-QSA sells under $20 shipped
Shipping to Canada ends up being the same price as the ConnectX-3 above. I was searching for MAM1Q00A-QSA and it would be $75CAD+ shipped. But this is definitely good enough.
 

kagurazakakotori

New Member
Mar 5, 2017
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These are MCX341A-XCAN network adapter from Quanta 2-node servers plus an OCP connector to PCIe adapter. The design of the OCP to PCIe adapter is available on GitHub:


And these single-port CX341A can be easily modified to a dual-port CX342A by soldering the second SFP cage, some electronic component, and crossflashing the firmware. Tutorials can be found at the second link above (in Chinese). Most of these dual-port adapters on sale, which the seller might call it CX342 or CX312, are the modified version of CX341.

The card and the adapter are very cheap in China, CX341 prices about 25 RMB, the modified dual-port version is about 60 RMB, the adapter is about 40 RMB.

These cards are really cheap, but these cards are hot, some of these assembled ones, especially these with metal case, are thicker than a PCIe slot, and these dual-port ones are probably not reliable as they are handmade.