Australian Lessons for Public Safety Broadband Network Resilience
With this week's massive Telstra mobile network failure [link], a fresh entry has been added to my LTE/5G network failure database. Joining the ranks of Optus (class of '23 and '25), Verizon (class of '26), Telefonica (class of '25), Rogers (class of '22), AT&T (class of '24 and '20), and other leading MNOs, the experience points to a major pitfall of moving mission critical communications from mature, hardened narrowband technologies such as TETRA, P25, and DMR to high-speed LTE/5G architectures.
Narrowband technology, while not immune from failure, has inherent mechanisms that can limit the breadth of failure. TETRA and P25 have failsoft trunking modes that permit local operation even when network elements are not operating, and the transmission site is isolated. And when the network is physically destroyed, the high power of narrowband radio devices -- personal and vehicle -- makes wide-area coverage restoration much easier than the equivalent coverage build required to capture the low-power up-link signals from LTE/5G mobile subscriber equipment.
In contrast to the architectural simplicity of modern digital narrowband systems, LTE and 5G operation can be "all or nothing". There is no isolated LTE/5G cell operation in a normal commercial network. Users can have superior capabilities one minute, and zero data support the next. The issue is architectural. LTE/5G network operation hinges on an intricate web of supporting IP technologies such as BGP, DNS, and NTP (the root source of Telstra's woes). The interconnected complexity can turn a minor software update into a national disaster when one of these elements fails. Even Facebook (class of '21) and Starlink (class of '25) are not immune to the occasional catastrophe from a fat-fingered CLI command, software update, or configuration error.
Public safety agencies must be mindful of the potential for failure in large-scale LTE/5G mobile networks, even those "built for public safety" ... because they all rely upon the same fragile fabric. Robust plans for alternatives when retiring narrowband technology are essential. Fortunately, the expanding canopies of LEO constellations, coupled with capable MCX architectures, can provide alternative pathways.
The need for PACE planning has never been greater. But the options available for alternative and contingent elements of the PACE plan have also never been more varied. But many options may be costly to hold in reserve when an entire fleet of vehicles and personal devices must be sustained. Just stroking my chin here, but existing proven narrowband networks working today may prove to be the most cost-effective alternative or contingent option. And, as unglamorous as it may be, it just works.