4G/5G Internet Failover for Melbourne Businesses

The Sophos XGS monitors the primary WAN connection using continuous health checks — small probe packets sent to reliable external hosts every few seconds. When the primary connection fails, the firewall detects the failure within 10-30 seconds and switches traffic to the 4G/5G connection. The total time from primary connection failure to cellular traffic flowing is typically under 60 seconds for active-passive failover. For most Melbourne offices, this means the disruption from an internet outage is a brief pause in activity rather than an extended outage — staff may notice a brief interruption to video calls or browser activity before everything resumes automatically.

Yes — the failover connection appears as a normal internet connection to all your devices and applications. Microsoft 365, Teams, SharePoint, cloud backups, VoIP telephony, web browsing, and any other internet-dependent service continues functioning on the 4G/5G connection. The cellular connection will typically have somewhat lower bandwidth and slightly higher latency compared to your primary NBN service, which means very high-bandwidth activities (downloading large files, running cloud backups) will be slower — but standard business activities including VoIP calls, Teams meetings, web browsing, and accessing cloud applications remain fully functional for most Melbourne offices.

Cellular data plans have data caps — unlike most business NBN plans which are unmetered. We select a data plan appropriate for your typical failover usage: for most Melbourne offices, a 50-100GB monthly data allowance is more than sufficient for occasional failover use, since the failover is intended to cover outage periods measured in hours rather than days. We monitor data consumption on the failover connection through Sophos Central and alert you if usage patterns suggest the plan may be at risk of exceeding its cap. If your business experiences frequent primary outages, we review and upgrade the data plan accordingly.

The 4G/5G modem is connected to the Sophos XGS firewall as a secondary WAN interface — either via ethernet from a USB or ethernet-capable cellular modem, or via a cellular router that presents an ethernet connection to the firewall. We configure the XGS with a dual-WAN policy defining the primary and secondary connections, the health check parameters, and the failback behaviour (when to return to the primary connection after it is restored). The cellular modem is placed at your site in a location with good signal — typically near a window — and we verify cellular signal strength and data throughput before considering the installation complete.

A 4G/5G failover solution for a typical Melbourne office involves a one-off hardware cost of $300–$800 for the enterprise-grade cellular modem, plus a monthly data plan of $40–$120/month for 50–200GB (more than sufficient for most failover scenarios). CX IT Services' managed configuration and monitoring of the failover is included in the broader managed service engagement at no separate line-item charge. Data plan contracts are typically month-to-month or 12-month — we do not lock clients into multi-year cellular plans given how quickly carrier pricing and 5G coverage improves. If you are not yet on a CX IT Services managed service, failover setup is available as a standalone project with an ongoing monitoring arrangement.

Yes, in the vast majority of cases. VoIP telephony (including 3CX) operates over the internet and is agnostic to whether the internet connection is NBN or 4G/5G — calls continue to route correctly as long as the cellular connection has sufficient bandwidth (each active VoIP call requires approximately 100Kbps symmetrically, which is well within 4G/5G capability). Cloud-connected EFTPOS terminals that communicate over the internet similarly continue functioning on cellular. The main limitation during failover is reduced total bandwidth — if your office normally has 250Mbps NBN and fails over to 50Mbps 4G, large file downloads and simultaneous video conferencing sessions may be slower, but standard business operations including calls, email, cloud apps, and payments remain fully functional.

No — and this is a critical design requirement. The failover is fully automatic and transparent to end users. When the primary NBN connection fails, the Sophos XGS detects the failure and switches routing to the 4G/5G interface within seconds, without any staff action required. Existing TCP sessions (browser sessions, Teams calls, active downloads) are preserved through the transition. Staff may notice a brief interruption of a few seconds during the switchover, but no reconfiguration, no Wi-Fi network change, and no application restart is needed. CX IT Services receives an automated alert when failover activates and contacts you to investigate the primary connection fault.

Certain Melbourne business types have formal business continuity obligations where internet redundancy is directly relevant. Financial services businesses with ASIC-regulated operations should document their business continuity arrangements, which increasingly include internet redundancy as a reviewer expectation. Medical practices subject to accreditation standards under the RACGP or similar bodies should document how they maintain access to clinical software and records during infrastructure failures. Professional services firms holding cyber insurance policies are increasingly asked whether internet redundancy is in place. CX IT Services provides a business continuity documentation package covering your failover configuration, tested failover procedures, and recovery time objective (RTO) evidence for use in insurance applications, regulatory submissions, and board risk reporting.

Simultaneous failure of both NBN and cellular connectivity is extremely unlikely — the two systems use entirely separate infrastructure and have essentially no common failure modes. NBN failures are typically caused by physical cable damage, carrier equipment faults, or exchange issues; 4G/5G failures would require a tower outage or widespread network event affecting the cellular carrier. In the very unlikely scenario where both connections are simultaneously unavailable, your staff continue working on any locally-hosted systems. For cloud-dependent businesses, this scenario is where a documented manual workaround process is valuable — for example, staff using mobile hotspots from personal devices as a tertiary option. CX IT Services documents the failure scenario and recommended workarounds as part of your business continuity planning for internet infrastructure.

When the 4G/5G failover activates, CX IT Services receives an automated alert from Sophos Central and proactively contacts you — in most cases you will hear from us before you have raised a support request. We simultaneously lodge a priority fault with your primary internet carrier and track the resolution. During the failover period, we monitor the cellular connection performance and alert you if data consumption is approaching the plan cap. Once the primary connection is restored, we supervise the failback to confirm the Sophos XGS transitions correctly back to the primary interface and that all traffic is routing as expected. A summary of the outage event — duration, cause (if determined by the carrier), and any data consumed on failover — is provided after each incident.