Category Archives: Systems

Fibre Optic Network LInk

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Introduction

As mentioned in an earlier post about a Fibre Connection Between the House and the Outbuildings there’s an 85m length of 8-core single-mode fibre running between the two buildings. While it’s possible to buy custom-made pre-terminated fibre, the relatively bulky end connectors make this much more difficult to pull through small ducts than unterminated fibre (which is only about 6mm diameter) – so while the fibre is already installed it’s not usable until it has been terminated. That wasn’t initially a problem since the fibre is really just future-proofing for the time when a network connection faster than 1Gb/s is required (or multiple physically-separate connections are required; the single CAT5E Ethernet cable already carries multiple logically-separate networks using 802.1Q VLAN tagging). Despite being close to the nominal length limit of 100m, this CAT5E cable was happily synched at 1Gb/s.

These days, single-mode (OS2) fibre is recommended over multi-mode (OMn) and rather than attempting to fit a connector to a 9 micron fibre on-site, the preferred approach is to fusion-splice a length of fibre which has already been terminated into a connector at one end, known as a ‘pigtail’. While automated fusion splice machines are expensive, they’re not uncommon and they’re designed to form high-quality splices even when used in challenging conditions (e.g. outside). For example, they’re carried by all the OpenReach technicians who install FTTP Broadband.

The decision to install single-mode fibre (rather than multi-mode) was straightforward, since single-mode is definitely “better” and is no longer significantly more expensive. However, there are several further design decisions required for other aspects of the fibre installation.

Simplex or Duplex?

Each of the 8 fibre cores can either be used as one half of a duplex link, where one core is used for Transmit and another for Receive (at a wavelength of 1310nm for single-mode fibre) or one core can be used for a bi-directional link (typically using 1310nm for one direction and 1550nm for the other). I took the view that 4 separate duplex links over the 8 cores was plenty of capacity – and dedicating a fibre to each direction seems less of a technical challenge than the bi-directional approach (and so less prone to issues, maybe?). Having said that, FTTP Broadband uses one single mode fibre for bi-directional communications and that works fine.1

Since the TX fibre at one end of a duplex link becomes the RX fibre at the other, it’s necessary to arrange for the fibres to be ‘swapped’ at some point along the route. Best practice is to swap them in the fixed section of the link so that it doesn’t matter whether the patch leads are straight-through or also ‘crossed’. (Duplex patch leads are in fact ‘crossed’ too, as standard, but provided there’s an odd number of crosses in an end-to-end link that’s fine.) This convention is part of the TIA 568 fibre cabling standard.

SC or LC Connectors?

There’s a huge range of fibre connector options but in practice the SC and LC types are the most common, with the older, metal bayonet-style ST connectors also fairly widely available . For duplex links two connectors are physically paired together. The smaller LC connectors are universal on duplex SFP transceivers and are increasingly common but the larger SC connectors seem slightly more robust for use in patch panels, so I settled on terminating the ‘fixed’ fibre links with Duplex SC connectors at each end.

Fibre patch leads with SC connectors at one end and LC connectors at the other are widely available – if anything more so than SC-SC patch leads.

DIY or Professional Fusion Splicing?

Automated fusion splice machines are expensive to purchase but can be hired for a few hundred pounds per week – if you know how to use them (and the related ‘cleaver’ tools). Then test equipment is required to ensure the spliced link performs to specification. I elected to commission local fibre optic specialist Fibrecomm Solutions Ltd to fusion-splice the pigtails onto the 8-core fibre (16 splices in total) and then test the links to validate the results.

Media Converters or SFP Modules?

Modern network equipment such as switches or routers is typically made compatible with fibre cabling via the inclusion of SFP or SFP+ sockets. It’s then the SFP(+) adaptor which takes account of whether the fibre is single- or multi-mode, simplex or duplex etc.2

Older equipment tends to only offer RJ45 sockets for Copper cabling – so then a separate Media Converter is required to convert between Copper and Fibre cabling. There’s quite a range of these available from different manufacturers. Some have SFP sockets which take optical modules but others have their own SC or LC sockets and tend to be cheaper. A few Media Converters accept a power feed via PoE.

I opted to use two of the TP-Link Omada MC210CS 1000Base-T to 1000Base-LX/LH Singlemode Fibre Media Converter, SC Connector (15km) units which incorporate pairs of SC sockets for duplex single-mode links. These take a 9V DC feed from a separate power adaptor but can be adapted for supply by PoE with a separate 9V-capable PoE Splitter such as the TP-Link Omada TL-POE10R, enabling them to be powered by a remote UPS.

  1. Out of interest, FTTP Broadband uses single mode fibre in a ‘simplex’ configuration (i.e. different frequencies along a single fibre for Transmit and Receive). The end connectors are coloured Green, indicating they are APC-style (rather than Blue for UPC-style). Another difference is that to avoid the need for active equipment ‘in the field’ there are passive optical splitters / combiners that form a Gigabit Passive Optical Network (GPON). ↩︎
  2. The SFP(+) adaptor receives power from the network equipment, which means that if the network equipment is powered via a UPS then the fibre link will stay up even if the grid power gets interrupted. ↩︎

UniFi Video –> UniFi Protect for CCTV Management

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The UniFi CCTV cameras around the House were originally part of a “UniFi Video” installation, for managing the cameras, storing recordings, easy access from a smartphone app etc. The UniFi Video software was hosted using a Docker Container running on an HP MicroServer with a relatively modest amount of CPU and disk capacity (but also a modest power consumption).

Ubiquiti stopped developing the UniFi Video software years ago (end of 2020?) so it has not been receiving any functionality enhancements or security fixes. Major security vulnerabilities such as Log4J were fixed in the Docker Container image but there are bound to be other vulnerabilities present – although the installation was isolated from the Internet, with remote access only possible via VPN, so it was not particularly at risk of compromise.

The replacement software, “UniFi Protect”, only runs on Ubiquiti hardware, so an in-place upgrade wasn’t possible (if it was I would have done it ages ago). I’m broadly supportive of Ubiquiti’s business model whereby an initial hardware purchase funds the development of their software – that’s much better than them requiring ongoing subscription fees – and it’s beneficial that all the data stays local, so I was happy to continue using the Ubiquiti equipment.

With the expansion of the CCTV installation to the Outbuildings, requiring the purchase of additional cameras (and thus placing additional load on the Network Video Recorder back-end) the time had come to switch to the UniFi Protect back-end. The newer (G5 and later) cameras didn’t want to be ‘adopted’ by UniFi Video anyway; G3s would be compatible but those are a poor-value investment these days.

This required the purchase of one of the UniFi hardware appliances able to run the UniFi Protect software (prices stated are as of mid-2025):

  • The various ‘Dream Machine’ appliances can run UniFi Protect alongside the UniFi Network Controller and can also act as a Network Gateway – but most of them only have space for a single disk drive, which didn’t seem adequate
  • The Dream Machine Pro Max has space for two drives – but it’s expensive; about £550 (inc VAT)
  • Then there are the dedicated Network Video recorder appliances:
    • The 4-bay UNVR; about £290 (inc VAT but excluding any disk drives)
    • The 7-bay UNVR-Pro; about £470 (inc VAT but excluding any disk drives)

I like the idea of having a dedicated NVR appliance (rather than the Dream Machine) – and I don’t want / need to change the network Gateway or Controller hosting at this time – so the 4-bay UNVR looked like the best option.

The approach of not including any disk drives as standard might seem odd but it gives the customer full control over how many drives to install, what drive capacity to choose and what brand/specification of drives to select. The drive bays accept either 2.5″ or 3.5″ SATA drives and there doesn’t seem to be much restriction on which brands and models can be used.

The CCTV cameras are constantly generating data so the drives have to work pretty hard. Specialist surveillance-specification drives are advisable to accommodate this type of workload. I opted for WD Purple Surveillance drives and installed two 4TB models, in a RAID5 configuration, leaving two further drive bays empty for later expansion. With only two drives, RAID5 allocates one of those as the ‘spare’ so the usable capacity is 3.96TB – the same as it would be with a RAID10 configuration – but if further drive(s) are added later, RAID5 makes all the extra drive space available.

Recordings are only purged once the storage gets full, so the volume of storage installed determines the retention period for recordings. After a few months of operation, 4TB of storage is giving about 120 days of retention for 12 cameras, at HD (rather than 4K) resolution and using ‘adaptive’ recording, which stores lower-quality video when no events are detected and higher-quality when there is activity identified. 120 days of retention seems perfectly adequate in a domestic setting.

While none of the new cameras include specific “AI” features such as facial recognition (it would be possible to retrofit “AI” processing to non-AI cameras using the UP-AI-Port device) there is some basic intelligent processing available as standard, detecting Vehicles, People or Animals. Sending me a real-time alert whenever a Vehicle is detected on the Driveway is working well.