QSFP-DD vs OSFP: choosing the right 400G and 800G form factor
Same headline speeds, very different decisions. QSFP-DD vs OSFP compared on electrical lanes, thermal headroom, backwards compatibility and the roadmap past 800G – plus the five things to check before you order.
Transceiver coding explained: one module, every platform
A switch rejecting a perfectly good optic is not an optical fault – it is an identification check. Here is how transceiver coding works, the inventory cost it creates, and how recoding collapses five lines of stock into one.
Do third-party optical transceivers void your warranty?
A compatible transceiver is a standards-built, hot-pluggable module – it does not modify your switch. Here is what OEM warranty terms actually say, what the law says about tie-in conditions, and the four steps that take the objection off the table.
How to spot a failing fibre link before it drops
Every transceiver in your network is measuring itself right now and reporting the results. Most networks never look until something has already gone down. That is a missed opportunity, because the most common fibre failure — a connection slowly getting worse — shows warning signs weeks in advance. You just have to know which number […]
MPO polarity explained: Type A, B and C in plain English
MPO polarity has one job: make sure the light leaving one switch arrives at the receiver on the other. Get it wrong and the link stays dark. It sounds complicated because of the naming. It is not. Here is the whole thing. The short answer Building a 400G or 800G link with parallel optics? Use […]
DAC vs AOC: which one should you actually buy?
If you need to connect two switches, you have three options: a copper DAC, an optical AOC, or transceivers with fibre between them. All three carry the same traffic. They cost very different amounts. Here is how to choose, without the jargon. The short answer Distance What to use Under 3 metres, same rack Passive […]
Optical transceiver testing: the 22 checks a module passes before it reaches you
Most suppliers will tell you their optics are tested. Very few will tell you what that means. So here is our optical transceiver testing process, in the detail it actually exists in. The modules we supply are built to a documented 22-step quality control process, and this article walks the whole thing — what is […]
JNP-QSFP-100G-LR4: the full specification, and the other part numbers for the same optic
JNP-QSFP-100G-LR4 is a 100GBASE-LR4 QSFP28 transceiver: four wavelengths, one duplex single-mode pair, 10 kilometres. That part is straightforward. What is not straightforward is that Juniper has published four names that resolve to the same physical module, and three more that look almost identical and are genuinely different parts. People order across those boundaries constantly, and […]
Choosing 400G optics: SR, DR, FR and LR, and what each one costs you in fibre
Choosing 400G optics looks like a distance problem. You know how far the link has to go, you pick the part that reaches that far, and you order it. It is not a distance problem. It is a fibre problem wearing a distance problem’s clothes — because the four letters on the end of the […]
BiDi transceivers: one fibre, two wavelengths, and the pairing rule that catches everyone
BiDi transceivers do something that sounds like it should not work: they carry a full-duplex link over a single strand of fibre. One strand, both directions, at the same time. They are also the source of more confused ordering than any other part of the optics catalogue — because the word “BiDi” is used in […]
