Aruba 40G QSFP+LC BiDi 150mMMF Transceiver (JL308A)

[N3tw0rk3r]

Hi guys,

I have a doubt about transceiver Aruba 40G QSFP+LC BiDi 150mMMF Transceiver(JL308A).

Does it use just only one f.o. wire? or it uses 2 wires (I need a duplex patch cord)?.

Regards

[Willem Bargeman · Accepted solution]

By default a 40Gbps transceiver needs a MPO patch cable. A mpo cable contains 12 fibers. 8 will be used by a 40Gbps connection. So 4 pairs of 10gbps.

This requirers new cable because the existing MMF is a different cable. Because of this we have to BiDi solution.

With 40Gbps bidi you need 2 MMF wires so a duplex cord. Per wire there is 20gbps using multi plexing.

[N3tw0rk3r]

Hi Willem,
So, this transceiver uses 2 strands, right?
You say each strand is 20Gbps using multiplexing (2 strands sum 40 Gbps managed by the transceiver). What does it mean? ... 20 Gbps inbound direction towards the transceiver @freq01 in a strand and 20 Gbps outbound direction of the transceiver @freq02 in the same strand?

[Willem Bargeman]

Yes, with this transceiver two fiber strands will be used. It's two times 20Gbit/sec ful duplex. See also this picture.

Quote from http://www.fiber-optic-solutions.com/know-bidi-transceiver.html

40G QSFP BiDi transceiver has two 20G channels, each transmitted and received simultaneously on two wavelengths over a single MMF strand (OM3 or OM4). It allows the existing 10G cabling system to be repurposed for 40G connectivity. Which means it lets you bring 40G speeds to the access layer using the same 10G cable plant you are using today. In contrast, the general QSFP SR4 transceiver like SR4 requires new patch cables and patch panels since the connector types differ and the size of the fiber trunk needs to be quadrupled."

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[Willem Bargeman]

See also this page

http://www.fiber-optic-solutions.com/know-bidi-transceiver.html

[N3tw0rk3r]

Thanks Willem for your clear explanation, it seems that these Bidi transceivers do not follow any IEEE standard and precaution must be taken among other brands.
Do you know if Aruba has a brochure that explains this working mode with diagrams like you posted? ... any aruba guy can confirm this?
Regards

[Willem Bargeman]

I don't know if there is any IEEE standard for QSFP+ BiDi.

However, MMF and BiDi is not really common except for QSFP+.

Do you know this guide? Contains all the information about the HPE/Aruba transceivers.

https://support.hpe.com/hpsc/doc/public/display?docId=a00028947en_us

[martyvis]

Thanks for this William. I'm doing a detailed design for a fitout that included these JL308A in the BOM and until finding this, I really thought that these would be using a simplex LC connector (as all BiDi transceivers I had seen to date do this). It's handy to know this when allocating cores in risers and ordering patch cables to not make the wrong assumption. At least I know everything on this project will be patched with LC duplex (some MM and some SM)

I'm wondering whether Aruba can update this guide with a simple matrix to show the specifics of connector types to really make it clear. (Also when you go to sites like https://www.hpe.com/au/en/product-catalog/options/pip.aruba-40g-qsfpplus-lc-bidirectional-150m-mmf-2-strand-transceiver.1010137527.html it would be good if right there it would clearly link to the required connector and patch cable type.

[N3tw0rk3r]

Hi Martin,

I think it would be a good idea Aruba could update the transceiver manual here (as you propose):

https://support.hpe.com/hpsc/doc/public/display?docId=a00028947en_us

because it does not mention that the transceiver uses 2 strands, like in your link:

https://www.hpe.com/au/en/product-catalog/options/pip.aruba-40g-qsfpplus-lc-bidirectional-150m-mmf-2-strand-transceiver.1010137527.html

Maybe a simple diagram like this one:

could clarify ideas about the form factor of the transceiver and could give users an idea of the fiber optics that should be used.

The problem here is that some people (I am included) tend to associate the term "BIDI" to 1 strand of fiber optics, as in the case of 1GE BIDI transceivers, but in the case of 40GE, the "BIDI" term is slightly different.

Regards

PS: Sorry for the delay setting the "accepted as solution" status Willem, thanks for the input

[voon]

Did anyone has the RMF (Read Me First) document for this?