One switch, three cable types
A switch has ports for short copper runs, a medium fibre run to another floor, and a long fibre run to the next building. The switch is the same box each time.
The difference is a small plug-in module in each port. Change the module and the same port serves a different cable.
Key words
| Word | What it means |
|---|---|
| Transceiver | a module with a transmitter and a receiver in one |
| SFP | small form-factor pluggable: a small hot-swap module, usually 1 Gbit/s |
| SFP+ | the same size as SFP but for 10 Gbit/s |
| GBIC | gigabit interface converter: an older, larger module |
| QSFP | quad small form-factor pluggable: four lanes in one module for 40 Gbit/s and more |
| Simplex | one direction only |
| Duplex | both directions at once, usually on two fibres |
| Bidirectional | both directions on one fibre, using two wavelengths |
| Wavelength | the colour of the light, measured in nanometres |
| Dynamic range | the range of light levels a receiver can read |
| Router | a device that passes data between networks |
| Network | devices joined so they can share data |
| Bandwidth | how much data a link can carry each second |
| Hot-swap | able to be plugged in or out while the device is on |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can name the four transceiver shapes and choose a module using the main criteria.
Starter: fibre and connectors
Have a go
Starter: fibre and connectors
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
The four shapes
| Name | Speed, roughly | Size and notes |
|---|---|---|
| GBIC | 1 Gbit/s | Older and larger. Seldom used in new work |
| SFP | 1 Gbit/s | Small. The most common starting point |
| SFP+ | 10 Gbit/s | The same size as SFP, a faster module |
| QSFP | 40 Gbit/s and more | Wider, four lanes. For top-of-rack and core links |
The cells students fill in are left blank in this preview.
Simplex, duplex and bidirectional
Simplex goes one way only. Duplex goes both ways at once, usually on two fibres: one to send and one to receive. A duplex module has a pair of LC plugs.
Bidirectional (BiDi) modules send both ways on one fibre, using two different wavelengths. They come in matching pairs, one at each end.
Check: direction
Have a go
Check: direction
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.