qsfp+ switch seems too good to be true

[AllenAsm]

Just found this on ebay and was wondering what I'm missing.

Dell S6010-ON 10/40GbE ToR Switch w/ 32-Ports of 40GbE QSFP "Without PSU or FAN" | eBay

Find many great new & used options and get the best deals for Dell S6010-ON 10/40GbE ToR Switch w/ 32-Ports of 40GbE QSFP "Without PSU or FAN" at the best online prices at eBay! Free shipping for many products!

www.ebay.com

So that will give me 32 ports of 40gbe? I still have to buy the modules and cards, but if I'm reading that right, I can get that baseline switch for $750. Are there other better deals like this out there?

also, i have some 10gbe devices (like my qnap), can I put a 10gbe / rj45 module in this and have it work?

 

[NablaSquaredG]

I can't say for this particular switch, but it's not too uncommon that you can get beefy 40G QSFP+ switches for little money (or even 56G QSFP+ when you stick with Mellanox).

Just keep in mind that these types of switches are usually loud and power hungry.

 

[i386]

Are there other better deals like this out there?

There were[1] better deals on 40GBE arista & mellanox switches for less on ebay. Every now and then there are arista 100GBE switches for $1.000 ~ $1.300 and 40GBE for <$500 bo

Quick search on ebay for "arista qsfp switch" shows still some good deals for arista gear, example: Arista DCS-7050QX-32 32-Port 40Gb QSFP+ 4x SFP+ Switch F-R Airflow 2x 460W PSU | eBay


[1]I stopped watching 40GBE stuff almost 2 years ago and started looking for 100GBE gear

Edit: I like the arista switches becaase there are many great deals on rear to front models and they support commands to lower the fan speed out of the box

 

[AllenAsm]

so is the key reason these are cheap because you have to use all mellanox or arista gear? What are my options and whats the downside to this?

 

[i386]

so is the key reason these are cheap because you have to use all mellanox or arista gear?

I'm still trying to find a brand that doesn't work on my mellanox or arista switches
I have tested mellanox, arista, ibm, finisar, cisco, fs.com, broadcom, brocade, netapp, dell, hp(e), intel and some other vendors that I already forgot transceivers/dacs and had no problems.

I ran a command to enable third party transceivers support on the arista though...

 

[Karl Austin]

Just found this on ebay and was wondering what I'm missing.

A power supply, fan tray and network operating system to start with

So that will give me 32 ports of 40gbe? I still have to buy the modules and cards, but if I'm reading that right, I can get that baseline switch for $750. Are there other better deals like this out there?

Much, as this isn't complete.

also, i have some 10gbe devices (like my qnap), can I put a 10gbe / rj45 module in this and have it work?

No. These are QSFP+ ports, you can get a QSFP+ to 4 x SFP+ to connect up your 10GE, but anything copper is out of luck unless you mess around with a QSA adaptor to convert QSFP+ to SFP - and they run about $70 each + SFP cost.

Look for Arista 7050 if you want cheap 40/10GBE.

 

[Mithril]

A power supply, fan tray and network operating system to start with


Much, as this isn't complete.


No. These are QSFP+ ports, you can get a QSFP+ to 4 x SFP+ to connect up your 10GE, but anything copper is out of look unless you mess around with a QSA adaptor to convert QSFP+ to SFP - and they run about $70 each + SFP cost.

Look for Arista 7050 if you want cheap 40/10GBE.

There are cheaper QSFP to SFP+ adaptors on ebay, but they are still a ridiculous price for a fully passive adaptor :-/ And the you get to deal with the hot running 10GE adaptors too, all in all not a great solution IMHO.

 

[AllenAsm]

based on the advice here, this looks like a great switch for what I need. If I buy this, what else do I need?

NEW Arista DCS-7050QX-32s-r 32-Pt QSFP+ 4x SFP+ Switch R-F Airflow Dual AC RAILS | eBay

NEW IN BOX Arista DCS-7050QX-32S-R. REAR TO FRONT AIR FLOW. ARISTA 7050, 32XQSFP+ & 4XSFP+ switch, rear-to-front air, 2xAC, 2xC13-C14 cords. 4x Fans (FAN-7000-r ). INCLUDES slide rails. 2x Power Cords.

www.ebay.com

I assume I also need the QSFP+ modules, whatever cables work with those, NICs for the 5 192g, 64 core, dual xeon servers these will connect together. What else?

Will the arista 7050 need any additional licenses?

 

[i386]

based on the advice here, this looks like a great switch for what I need. If I buy this, what else do I need?

NEW Arista DCS-7050QX-32s-r 32-Pt QSFP+ 4x SFP+ Switch R-F Airflow Dual AC RAILS | eBay

NEW IN BOX Arista DCS-7050QX-32S-R. REAR TO FRONT AIR FLOW. ARISTA 7050, 32XQSFP+ & 4XSFP+ switch, rear-to-front air, 2xAC, 2xC13-C14 cords. 4x Fans (FAN-7000-r ). INCLUDES slide rails. 2x Power Cords.

www.ebay.com

I assume I also need the QSFP+ modules, whatever cables work with those, NICs for the 5 192g, 64 core, dual xeon servers these will connect together. What else?

Will the arista 7050 need any additional licenses?

This is a model with rear to front airflow (blue fans & psus show where the cold air is)
No additional licenses are required.

 

[AllenAsm]

I have a 42u colo cabinet with at least 16u of space available so the rear to front airflow won't really be a problem for me (maybe just longer cables).

I bought that switch and it should be delivered next week.

I found some qsfp+ to 4x rj45 10gbe cables which should solve my need for some 10gbe ports super cheaply. The only downside is I can't individually manage those 4 ports. Should be fine though since I need them to send data to/from an enterprise qnap device.

Now I need to get 5 qsfp+ NICs and some qsfp+ cables to tie this all together. I'm assuming this all works on both linux and windows 2019.

Anything else I'm going to need for this? This will be put into my personal hyper v lab so everything will have to work with that.

 

[NablaSquaredG]

I actually prefer rear to front airflow on switches, because I usually mount the switches on the back of the rack (not the front). Makes cable management much easier imho.

 

[Karl Austin]

I actually prefer rear to front airflow on switches, because I usually mount the switches on the back of the rack (not the front). Makes cable management much easier imho.

Same. Much easier having ports at the back along with the ports for the servers. Makes cable management massively easy compared to running from front to back.

 

[klui]

Switches in the hot aisle is standard operating procedure in the data center. It's just for the home you can't see those blinking lights and for those like me who have wall-mounted shallow racks impractical to mount them that way.

 

[AllenAsm]

Quick question, I have the arista dcs-7050qx-32s-r qsfp+ switch. This is all going into my 42u colo cabinet so I don't need to reach anything else. Do I need an active or passive transceiver? I'm looking at this one on fs.com.

Arista Networks 40G QSFP+ QSFP-40G-SR4 Transceiver - FS.com

Check Arista Networks QSFP-40G-SR4 Compatible 40GBASE-SR4 QSFP+ transceiver module data sheet (MMF, 850nm, 150m, MTP/MPO connector) & price list on FS.COM, buy now!

www.fs.com

It says its rated for 150m which is about 148m more than I need. Are there cheaper ones that would work fine as well? Is this even the right one I need? some say bi-directional but this one doesn't?

 

[NablaSquaredG]

This transceiver has MTP/MPO connectors which means that it needs 12 fibres (8 are actually going to be used). MTP/MPO cables are kinda expensive.

If you only need 2m - Why not use a Direct Attach Cable? That would be much cheaper.

 

[AllenAsm]

Because I'm a noob on sfp in general. heh. What do I need and I'll get it. 2 or 3m should likely be plenty to reach anywhere in the 42u. Can you give me a link to what I might need?

 

[NablaSquaredG]

3m Generic 40G QSFP+ DAC Twinax Cable 28AWG - FS.com

Check Generic Compatible 40G Passive Direct Attach Copper Twinax Cable data sheet (DAC Cable, QSFP+ to QSFP+, 3m, 28AWG) data sheet and price list on FS.COM, buy it now!

www.fs.com

This could be what you're looking for

 

[AllenAsm]

Thats perfect. another stupid question.... do those cables include the transceiver? Do I need to buy separate modules to put in this switch?

 

[NablaSquaredG]

Those cables don't have optical transceivers (which is probably what you were referring to). Fixed-length optical cables are called "AOC" (Active Optical Cable), but this is a DAC (Direct Attach Cable).

An optical transceiver converts from electrical to optical signals, which is generally needed if you want to transmit the data over long distances. The definition of "long" depends on the data rate. The higher your data rate the shorter the distance for which you can use passive Direct Attach Cables.

In Summary:
There are three ways to transport (QSFP) data

• Passive Direct Attach Cables -> Only work for short distance, inexpensive
• Active Optical Cables -> Can work over long distances, but are naturally fixed length. Much more expensive
• Optical Transceiver + fibre -> Up to 20km depending on your fiber and transceiver type. More expensive, but often the only possibility

Regarding this:

Do I need to buy separate modules to put in this switch?

No. That's why it's called a "Direct Attach Cable". Just plug it in and that's it.

(Q)SFP is a very flexible interface, because it works with both passive (direct attach cables) and active (AOC, Transceiver) devices

 

[i386]

another stupid question.... do those cables include the transceiver?

That's not a stupid question. Transceiver are devices that can transmit and receive signals, be it optical, electrical or other forms and are the electronics in qsfp(+), sfp(+), cxp, xfp modules. So yes, these cables include the transceivers.

• Passive Direct Attach Cables -> Only work for short distance, inexpensive
• Active Optical Cables -> Can work over long distances, but are naturally fixed length. Much more expensive
• Transceiver + fibre -> Up to 20km depending on your fiber and transceiver type. More expensive, but often the only possibility

There is also a fourth category: active dac cables that allow distances up to 20m, rare -> expensive, same problems that other copper cables have