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QoS and Voice on Shared Business Broadband
Quality of Service tells your router which packets jump the queue when the link is saturated. On a single FTTP/FTTC handoff shared by staff PCs, guest Wi-Fi and desk phones, sane QoS prevents Dropbox sync from stomping on G.711 RTP — but it cannot conjure bandwidth the ISP never sold you.
Next step: Match circuit headroom to peak concurrent voice. Contact us for router models that honour DSCP end-to-end.
Marking: EF, CS5 and “voice VLAN”
Phones or managed switches can tag RTP with EF; routers then map that to a strict priority queue. If your PBX is cloud-only, marking may happen at the handset or not at all — policy on the LAN edge still helps before NAT.
Upstream is the usual villain
QoS shapes outbound queues you control. Inbound congestion from the internet is harder — reduce parallel downloads or buy more download Mbps. See speed planning.
SIP ALG and “helpful” firewalls
Disable SIP ALG on most routers; it mangles headers. Consistent UDP timeout values beat random “VoIP optimisation” tick boxes — pair with guidance in latency guide.
When to split traffic physically
High-call-volume contact centres sometimes run a second cheap broadband solely for voice or use 4G/5G failover that fails over voice-first.
Related guides
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