Connecting Mellanox CX3 to Juniper EX2300C switch?

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zer0sum

zer0sum

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Mar 8, 2013
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Hello,

I have been enjoying a couple of cheap Mellanox ConnectX-3 cards connected directly to each other with a DAC cable, but I'm looking to move to a longer link with Juniper EX2300C switches at each end.

The EX2300C has 2 x 1/10GbE SFP/SFP+ ports that can be used.
I'm going to use one as a long uplink between the 2 switches, and I think I have that figured out with some transceivers and a ~100ft fiber cable.
Datasheet is here - https://www.juniper.net/assets/uk/en/local/pdf/datasheets/1000580-en.pdf

With the other spare SFP+ switch port I want to connect my PC and NAS directly to each switch at either end, and I was wondering if I can still use my Mellanox cards to achieve this?
And, if so, then what sort of transceivers do I need?

Any help greatly appreciated :D
 
Blinky 42

Blinky 42

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Yes you can use SFP+ with your Mellanox cards. You can probably use the existing DAC cable to connect one of the card to the switch, and then get a pair of SFP+ SR optics to connect the other switch to the other NIC.
 
zer0sum

zer0sum

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The DAC cable I have won't work at the switch end because it's a lot thicker than the EX2300C ports :(

EX2300C is small and thin looking.
Mellanox is fat and burly :)
 
Blinky 42

Blinky 42

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What connect-x 3 card do you have? Does it have a QSFP port on it instead for 40Gb? They are roughly 2.5 times as wide as they are thick where as the SFP+ and SFP28 ports are close to square.
Example QSFP DAC cable Mellanox MC2210130-002 40G QSFP+ DAC Cable
Example SFP+ DAC cable Mellanox MC3309130-002 10G SFP+ DAC Twinax Cable

For all optical
Then 4 of these for the switch side Juniper EX-SFP-10GE-SR 10GBASE-SR SFP+ Transceiver Module
And the NIC side Mellanox MFM1T02A-SR 10GBASE-SR SFP+ Transceiver Module + Mellanox MAM1Q00A-QSA-SP (Single Pack MAM1Q00A-QSA) Ethernet Cable Adapter 40Gb/s to 10Gb/s QSFP to SFP+
I would look on ebay for the Mellanox MAM1Q00A-QSA they are ~ $20 there.
 
zer0sum

zer0sum

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Awesome information...thank you :)

I grabbed 2 x MAM1Q00A-QSA for $44 off Ebay and will see if my current SFP+ transceivers work
 
Blinky 42

Blinky 42

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zer0sum said:
Would this OM3 LC to LC cable work?

Customized Length LC UPC to LC UPC Duplex OM3 Multimode LSZH 2.0mm Fiber Optic Patch Cable
Click to expand...
Yes with any SR transceiver with LC connectors the OM3 or OM4 would work. The OM4 is better spec'd fiber with less attenuation so it can support longer runs at higher bandwidth but for distances of 100ft or so it isn't a big deal unless you want to plan ahead for the future.

For "long" runs (over 200ft or so) you will want singlemode fiber and LR transcievers. The OS2 cable in the yellow jacket vs the multimode OM3/OM4 in the Auqa jacket. In data centers you will often see all singlemode for any distance that isn't within a few cabinets, and many places will just standardize on single mode everywhere to avoid having other spares to stock.
 
zer0sum

zer0sum

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Thank you so much for your help Blinky :)

I know networking, but I don't have much, if any experience with all the different fiber standards.

I have some LR transceivers on hand, and I want to run a 30-40m cable along the outside of my house under the eaves.
Can I just use them with OM3/OM4 or would it be worth switching to SR transceivers?
 
Blinky 42

Blinky 42

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the OM* cable won't work well/at all with LR optics. Mixing cable/transceiver on a real short patch cable may bring the link up by brute force but it really isn't something to spend any time or effort on.

SR optics + OM3/OM4 cables are designed to pass multimode light down the fiber at 850nm.
LR optics (in all their formats) are designed for Single-Mode fibers and for your purposes will operate around 1310nm+.

Because the fibers are setup to behave well for the different scenarios, that is why you can't really mix and match and hope that it will work well.

Single Mode also is where all the real carrier circuits with higher powered optics for 10/40/100km long runs, and more creative situations are found. You may have seen people talking about "BiDi" transceivers that use a pair of wavelengths on a single fiber instead of a pair of unidirectional fibers for traffic in each direction.
Stepping up from that you will encounter CWDM/DWDM optics that are set of a specific pair of wavelengths, or tuneable optics where you can control the wavelengths in software.

I would personally get some armored weather resistant single mode cable and run that if you are doing a run inside & outside of the house. If oyu are taking the effort to run cable, you can always get multi strand fiber and run that + use patch panels / break out boxes at each end to plan for future upgrades / allow for more than one pair of fibers between locations.
 
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