Telcos are speeding on two Achilles heels

The world’s telcos are leaving themselves dangerously exposed by their emergency reliance on satellite, according to the CTO of a top telco technology vendor. The war in Ukraine has exposed weakness in Europe’s comms infrastructure and in particular 5G’s reliance on insecure satellite signals such as GPS/GNSS for time synchronisation, warned Per Lindgren, Group CTO and Head of Sync at technology vendor Net Insight. As a result European nations are facing a heightened security threat to their sovereignty. Though Türk Telekom and the Swedish Post and Telecom Authority have shown initiative in combatting this threat, most European telcos need to do more, Lindgren writes.

As 5G rolls out reliance on satellite signals is increasing as it offers fast coverage options. This also presents opportunities for malicious denial of service acts that could go beyond consumer inconvenience into the disabling the emergency and military services that are starting use 5G’s low latency. Telcos face a crisis, they must find a stable, satellite-independent time synchronisation solution for 5G, but today’s alternatives are too small and too expensive. Networks need an alternative that does not rely on satellites or that is expensive to deploy and operate, warned Lindgren. The solution might be a new time synchronise that uses existing networks to provide a more reliable timing precision.

The problem is that 5G’s strength, its timeliness, is also its weakness. Its use of Time Division Duplex (TDD) is looking questionable now, according to Lindgren. Since TDD has to keep accurate time across the network, the scale of that challenge multiplies out of control in the age of the cloud. TDD’s reliance on ‘fleet of foot’ mechanisms for precision timekeeping has twin Achilles Heels.

One weakness is the global time synchronisation provided by satellite constellations like GPS/GNSS, because they’re inherently unstable. Disruption of satellite signals diminishes reliability and service availability and that varies with the weather conditions. It’s bad enough that when it’s cloudy, there’s a chance of scattered timing dysfunction and that rain can stop play but the Ukraine war has showed that rogue nations can jam GPS signals and listen in and disturb radio communication. The intentional signal jamming during the war in Syria spilled over into national network operations in Turkey – even though it was not part of the conflict.

“For now, it is contained in warzones and neighbouring countries, but it is not hard to imagine a malicious actor using a similar kit to disrupt satellite signals and cause severe damage to national networks,” said Lindgren. The second Achilles Heel of Satellite is their use the IEEE standard Precision Time Protocol (PTP) which relies on one master clock sending timing signals over standard IP links. While PTP is usually installed in radio access equipment, it must still be installed on every line card through an operator’s network making it an expensive solution to deploy and operate. While PTP may operate independently of satellite networks and bring sought-after sovereignty, it carries significant cost, implementation and manageability drawbacks that make it fundamentally unviable.

“Operators must find alternatives with equally precise timing precision and satellite independence but less complex and costly,” said Lindgren, “the use of GPS/GNSS in mobile networks highlights the potential risk of communications infrastructure. Policymakers to consider carefully how sovereign their networks really are,” said Lindgren. Some nations have such a heightened awareness of their reliance on satellites in these networks that they have mandated the implementation of solutions that are independent of satellite signals. In Turkey, for example, the proximity to major conflict zones encouraged Türk Telekom to roll out a GPS/GNSS independent solution throughout its network in late 2021 and it is playing a leading role in standardising the solution globally. In Sweden, the regulator has mandated mobile operators to solve synchronisation of their 5G networks independent of GPS/GNSS systems or they will lose their license.

Systems that can be distributed over existing IP links negate the need for PTP timing support in every intermediate node. If paired with a centralised controller and microservice design, operators can get real-time visibility over the network and more flexibility in how they choose to scale. When operators do choose to expand rapidly, the competitive advantage of such a synchronisation is its ability to deploy over existing core and aggregation networks including leased lines which significantly reduces rollout time and cost to rural and regional areas as no forklift upgrades are required.

“There is a rapidly growing need for synchronisation solutions that do not rely on any external source for timing, that are disaggregated and easily distributed and managed across an entire network,” said Lindgren.