Layla UsmanThe move away from copper and toward internet-delivered voice is no longer a future trend, it’s the standard. For Australian businesses that still rely on PSTN lines or complex multi-line PABX estates, SIP trunking (Session Initiation Protocol) is the practical path to lower costs, more capability and better resilience, especially when paired with the right business NBN or fibre plan.
At BroadConnect we design and manage SIP trunk solutions that connect your Cloud PBX, unify voice and data, and enable modern streaming media (video, screen-share and conferencing) without the brittle behaviour of legacy systems. This guide explains what SIP trunking is, why it matters for VoIP and streaming media, how it saves money, and how to choose the right architecture for Australian workplaces.
What is SIP trunking — simply explained
SIP trunking replaces traditional PSTN phone lines with one or more virtual “trunks” delivered over the internet. Instead of the old model of “one phone number per physical line,” SIP trunks carry multiple concurrent calls on-demand and can carry signalling for voice, video and messaging. When coupled with a Cloud PBX or modern IP-PBX, SIP trunking turns your internet connection into a single, flexible communications backbone.
If you run Microsoft Teams, a hosted phone system or a multi-site contact centre, SIP trunks provide the gateway between your telephony platform and the public telephone network while keeping signalling and media flows under your control. Learn more about integration options with our Cloud PBX and Microsoft Teams Calling.
Why SIP trunking is the natural companion to streaming media
SIP isn’t only about voice. It carries session signalling for multimedia — video calls, desktop sharing, and real-time collaboration — making it ideal for modern streaming workflows. When you pair SIP trunks with a properly sized business NBN or fibre connection, you get low-latency streams, reliable video conferencing and high-quality VoIP in one converged pipe.
This convergence matters for hybrid workplaces and contact centres that use conversation intelligence, call recording, and real-time transcription. BroadConnect’s solutions link SIP trunking with compliant AI transcription and call recording so you can stream meetings, capture transcripts on-shore, and keep your data inside Australian borders.
Cost, reliability and capability — what SIP gives you
SIP trunking unlocks four practical benefits for businesses:
- Lower ongoing voice costs. SIP lets you consolidate multiple lines into a single trunk and reduce international/long-distance charges.
- Elastic capacity. Add simultaneous call capacity as you need it without installing new copper lines.
- Unified media support. Voice, video, messaging and conferencing flow over the same architecture.
- Resilience options. Combine SIP with 4G/5G failover or SD-WAN so voice survives internet interruptions.
For many organisations, these advantages translate into a simpler telephony estate and a smaller monthly bill — particularly compared with maintaining aging PSTN infrastructure.
Quick comparison: PSTN vs SIP trunks vs Hosted PBX
| Feature | PSTN (copper) | SIP Trunks + On-prem PBX | Hosted PBX / Cloud phone |
| Upfront hardware | High | Medium | Low |
| Scalability | Low (physical lines) | High (license-based) | Very high |
| Cost predictability | Variable | More predictable | Subscription-based |
| Supports video/streaming | Limited | Yes | Yes |
| Geographic number flexibility | Regional constraints | Easy porting/virtual numbers | Very flexible |
| Disaster recovery | Limited | Can use multi-link failover | Provider-managed redundancy |
BroadConnect can help you evaluate which mix is right — whether full cloud, hybrid PBX with SIP trunks, or a staged migration. See our business phone systems and hardware provisioning services.
Typical migration path and technical checklist
Most businesses follow a staged approach: assess current PSTN usage, size SIP trunk concurrent call volume, provision business-grade internet (NBN/fibre), configure QoS and voice VLANs, and pilot with a small user group. Key technical checks include:
- Confirm upload bandwidth headroom for concurrent RTP streams.
- Configure QoS (diffserv) so voice packets are prioritised over bulk traffic.
- Disable SIP ALG on edge routers or use a managed SBC for NAT traversal.
- Ensure codec alignment (G.711, G.722, Opus) between PBX and provider.
- Prepare number porting/redirect rules and testing windows.
BroadConnect’s managed IT & networking and SIP trunking services handle these steps end-to-end.
ROI example: what savings look like
| Example business | 10-seat office, 6 concurrent calls | Annual PSTN cost (est.) | Annual SIP+connectivity cost (est.) |
| Small professional firm | 6 | $6,000 | $2,400 |
| Difference | — | — | ~60% savings |
Actual numbers vary by call profile and international usage, but many BroadConnect customers report substantial reductions in telephony expenditure after switching to SIP trunks combined with optimized business NBN or failover via business mobile plans.
Our business has been using Broadconnect Telecom services for over 5 years. We have more than 600 devices across 14 large scale healthcare centres. Their VoIP solution is best in its class. The team at Broadconnect are a pleasure to work with – highly competent, very efficient & always responsive.
SIP trunking and compliance: what Australian firms must consider
If you record calls, handle sensitive client data, or work in regulated industries (healthcare, finance, legal), ensure your SIP and streaming architecture meets privacy expectations. Ask your provider about on-shore media handling, encrypted signalling (TLS/SRTP), retained transcript controls and secure storage. BroadConnect supports compliant deployments and can integrate with our cybersecurity and transcription partners to keep your data protected.
Where streaming media fits: use cases
SIP trunks make these use cases practical and affordable:
- High-quality video conferencing and client consultations.
- Screen-share and remote assistance with low latency.
- Contact centre multimedia interactions (voice + chat + co-browsing).
- Live webcasting and internal town-hall streaming.
For contact centres, SIP combined with cloud platforms improves scalability and integrates with conversation intelligence and AI voice agents to surface insights from every interaction. See our contact centre solutions for examples.
Choosing a SIP trunk provider — practical questions to ask
When reviewing providers, check for these capabilities:
- Local Australian presence and on-shore media handling.
- Clear explanations of codec, RTP port ranges and NAT/SBC support.
- Flexible concurrency and easy scaling without long lead times.
- Number porting assistance and geographic DID options.
- SLAs for call success rates and packet-loss thresholds.
BroadConnect partners with reliable carrier backbones and can design a resilient SIP strategy that includes multi-link failover and managed SBCs.
Final thoughts — SIP is a business decision, not a technical fad
SIP trunking is no longer niche. It’s the practical foundation for modern VoIP, unified communications and streaming media. For Australian companies, the transition is about more than cost: it’s about future-proofing communications, enabling hybrid work, and consolidating voice and media on a single resilient platform.
If you’re ready to evaluate SIP trunking for your sites in Sydney, Melbourne or regional Australia, BroadConnect can run a free environment assessment, model expected savings, and pilot a migration with minimal disruption. Start the conversation: Contact BroadConnect.e flows for those tasks and measure completion rates. Any flow with an error or abandonment above 3% should be reworked. Record calls and use transcripts to run two-week A/B tests on voice persona and prompt wording; small wording changes often yield big containment wins.
Ready to Upgrade?
Talk to our Sydney-based team today to find out how BroadConnect can transform your business communications.
📞 Book a Consultation or email us at hello@broadconnect.com.au to get started.
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Visit us: Level 26, 1 Bligh Street, Sydney NSW 2000
Call: 1300 880 330
Email: hello@broadconnect.com.au