QoS Settings for VOIP on NBN Router (2026)

QoS (Quality of Service) tells your router to prioritise voice packets over other traffic, reducing jitter, latency, and packet loss during VOIP calls. This guide explains what QoS does, how it works at the packet level, how to configure it on common Australian routers (Telstra Smart Modem, TP-Link, Ubiquiti), and, critically, when QoS actually helps versus when it makes no difference at all. If your VOIP calls sound choppy, robotic, or drop out during busy network periods, QoS configuration is the first thing to check. But if your connection has plenty of headroom and few users, QoS may do nothing measurable. This guide helps you figure out which situation you are in.

What QoS Actually Does

Your router handles all traffic on your network. Web browsing, file downloads, streaming video, cloud backups, and VOIP calls all flow through the same connection. Without QoS, your router treats all packets equally. It sends them in the order they arrive, first in, first out.This is fine when the connection is not congested. But when someone starts a large file download, streams a 4K video, or uploads a cloud backup, the router's outbound queue fills up. Voice packets from your VOIP call get stuck behind hundreds of data packets. They arrive late (latency), arrive out of order (jitter), or get dropped entirely (packet loss).Human ears are extremely sensitive to these issues. A 150ms delay makes conversation awkward. A 200ms delay creates crosstalk where both parties talk over each other. Jitter above 30ms causes robotic, choppy audio. Even 1-2% packet loss creates gaps in the conversation where words disappear.QoS solves this by giving voice packets priority. When the router's queue is congested, voice packets jump to the front. Data packets wait. The file download slows slightly. The video buffers for a moment. But your phone call stays clear. QoS does not create more bandwidth. It manages the bandwidth you have more intelligently by ensuring time-sensitive traffic goes first.

How QoS Works at the Packet Level

Understanding the basics makes configuration much easier. You do not need to be a network engineer, but knowing what DSCP and ToS mean will help you understand what your router's QoS settings are actually doing.

DSCP and ToS Markings

Every IP packet has a header field called the Type of Service (ToS) byte. Within that byte, the Differentiated Services Code Point (DSCP) is a 6-bit value that tells network equipment how to handle the packet. Think of it as a priority label stamped on each packet.For VOIP, two DSCP values matter:EF (Expedited Forwarding) - DSCP 46: This is the standard marking for voice media (the actual audio stream, also called RTP traffic). Packets marked EF get the highest priority in any QoS-aware queue. Every major VOIP phone and softphone marks its audio packets with DSCP 46 by default.CS3 (Class Selector 3) - DSCP 24: This is typically used for SIP signalling traffic (the packets that set up, maintain, and tear down calls, not the audio itself). Signalling needs to be reliable but is not as latency-sensitive as audio. Some devices use AF31 (DSCP 26) instead. The exact value matters less than ensuring signalling gets higher priority than best-effort traffic.

Queuing Mechanisms

When your router receives packets with different DSCP markings, it places them into different queues. The most common mechanism is Strict Priority Queuing, where the highest-priority queue (voice) is always served first. Only when the voice queue is empty does the router process the next queue down.Some routers use Weighted Fair Queuing (WFQ), which allocates a percentage of bandwidth to each queue rather than absolute priority. WFQ is gentler on lower-priority traffic but slightly less protective of voice during heavy congestion. For most small business scenarios, either mechanism works. The important thing is that voice traffic is in a higher-priority queue than general data.

When QoS Helps and When It Does Not

This is the most important section in this guide. QoS is not a magic fix for all VOIP call quality problems. It solves one specific problem: local network congestion at your router. If that is not your problem, QoS will make zero difference.

QoS Helps When

Your connection is shared and regularly congested. A small office with 5 to 10 people on the same internet connection, some streaming, some downloading, some on VOIP calls. The upload link gets saturated during business hours. QoS ensures voice packets get through first. This is the classic QoS use case and it works very well.Your upload bandwidth is limited. This is common on NBN FTTN and HFC connections where upload speeds are 5 to 20 Mbps. A single large upload (cloud backup, sending a video file, uploading to a CRM) can consume most of your upload bandwidth. Without QoS, voice packets compete with the upload. With QoS, voice packets go first.You have a specific, repeatable quality issue. Calls sound fine first thing in the morning but degrade after 10am when everyone is working. Calls drop when someone starts a Teams meeting. Audio goes choppy when the cloud backup runs. These patterns point to congestion, and QoS is the right fix.

QoS Does Not Help When

Your connection has plenty of headroom. If you have a 100/40 Mbps NBN connection and three people in the office, your connection is never congested. QoS has nothing to manage. Voice packets are already getting through fine because there is no queue to jump.The problem is upstream from your router. If the quality issue is in the NBN network itself (congestion at the POI, a degraded FTTN copper line, or an HFC node serving too many premises), QoS on your router cannot fix it. Your router only controls traffic within your local network and on the outbound path to your ISP. Once packets leave your router, they are subject to whatever happens on the ISP and NBN network.Your ISP modem strips DSCP markings. Some ISP-supplied modems reset the DSCP field to 0 (best effort) on all outbound packets, regardless of what your internal devices set. If this happens, your carefully configured QoS is being erased at the point where it matters most. This is common on Telstra Smart Modems in default configuration. The fix is to put the ISP modem in bridge mode and use your own router for QoS.Your phones are on WiFi. VOIP phones should always be on wired Ethernet. WiFi introduces its own latency and jitter that QoS cannot control. If your phones are on WiFi and call quality is poor, switch to wired before touching QoS settings.

How to Configure QoS: General Steps

The specific steps vary by router brand and model, but the general process is the same. Complete these steps in order.Step 1: Identify your VOIP traffic. You need to tell your router which traffic is voice. There are three common methods: by DSCP marking (the router reads the DSCP value already on the packets from your VOIP phones), by port number (SIP uses UDP port 5060 for signalling and UDP ports 10000-20000 for audio, though ranges vary by provider), or by device IP address (you assign static IPs to your VOIP phones and tell the router to prioritise traffic from those IPs).Step 2: Create a high-priority queue for voice. In your router's QoS settings, create a traffic class or rule that matches your VOIP traffic and assigns it to the highest priority queue. The exact terminology varies: some routers call it "High Priority" or "Voice" or "Expedited Forwarding."Step 3: Set bandwidth limits. Many QoS implementations work best when you tell the router your actual upload and download speeds. Set these to about 85-90% of your measured speeds (not the plan speed, but what you actually get). This gives the QoS engine room to manage the queue before the connection is fully saturated.Step 4: Test. Make a call while simultaneously running a speed test or large download. If QoS is working, the call stays clear while the download speed drops slightly. If the call still degrades, check that your rules are matching the correct traffic.

Router-Specific Configuration Guides

Telstra Smart Modem (Gen 2 and Gen 3)

The Telstra Smart Modem has limited QoS capability in its default configuration. It does support basic traffic prioritisation, but the controls are simplified compared to a dedicated router.Access the admin interface: Open a browser and go to http://192.168.0.1 (or http://mymodem.modem). Default username is admin, password is on the sticker on the bottom of the modem.Navigate to QoS: Go to Advanced > QoS (the exact path may vary by firmware version). Enable QoS if it is not already on.Set WAN speeds: Enter your actual measured upload and download speeds. Use a speed test (fast.com or speedtest.net) during off-peak hours to get accurate numbers. Set QoS limits to 85-90% of these measured values.Add voice priority rule: Create a new rule matching UDP ports 5060 (SIP signalling) and 10000-20000 (RTP audio). Set priority to "High" or "Highest." Alternatively, create a rule matching DSCP value 46 (EF) and set it to highest priority.Important limitation: The Telstra Smart Modem is known to strip DSCP markings on outbound traffic in some firmware versions. If you configure DSCP-based QoS and it does not work, switch to port-based rules instead. For businesses with more than 3-4 VOIP handsets, consider putting the Telstra modem in bridge mode and using a dedicated router (see Ubiquiti section below).

TP-Link Routers (Archer series, Omada series)

TP-Link routers have good QoS support, especially the Omada business range. The consumer Archer series has a simpler QoS interface but it works.Archer series (consumer): Access the admin at http://192.168.0.1 or http://tplinkwifi.net. Go to Advanced > QoS. Enable QoS and set your upload/download bandwidth to 85-90% of measured speeds. TP-Link Archer QoS uses device-based priority. Add your VOIP phones by IP or MAC address and set them to "High Priority." This is simpler than DSCP-based rules but effective.Omada series (business): If using an Omada controller (OC200 or software controller), go to Settings > Wired Networks > Internet > WAN > Rate Limit and configure bandwidth limits. Then go to Settings > Network Security > ACL > Switch ACL and create rules matching DSCP 46 to a high-priority queue. The Omada platform supports proper DSCP-based QoS and is a solid choice for small business VOIP.For the Omada gateway (ER605 or ER7206), configure QoS under Transmission > Bandwidth Control. Create a rule for VOIP traffic by port range (UDP 5060, UDP 10000-20000) or by DSCP value. Set the guaranteed bandwidth to at least 1 Mbps for voice (enough for approximately 10 concurrent calls) and the priority to "High."

Ubiquiti (UniFi Dream Machine, USG, UDM Pro)

Ubiquiti's UniFi platform is popular with AU businesses and IT consultants. It has strong QoS capability through its "Smart Queues" feature and custom traffic rules.Smart Queues (the easy way): In the UniFi Controller, go to Settings > Internet > WAN. Enable Smart Queues and set your download and upload speeds to 85-90% of measured values. Smart Queues uses a form of FQ-CoDel (Fair Queue Controlled Delay), which automatically manages bufferbloat and gives interactive traffic like VOIP a fair share. For many small offices, this single setting is enough without any further configuration.Custom traffic rules (for more control): Go to Settings > Traffic Management > Traffic Rules. Create a new rule: match protocol UDP, destination port range 5060 and 10000-20000, action "Set DSCP" to EF (46), queue to "Voice." This ensures voice traffic is explicitly classified and handled with the highest priority.DSCP trust on switch ports: If you are using UniFi switches, make sure the switch ports connected to your VOIP phones are configured to trust DSCP markings. Go to Devices > [Switch] > Ports > [Port] > Profile and select the "VoIP" profile or create a custom profile that trusts incoming DSCP markings. This ensures the DSCP 46 marking from your phone is preserved as the packet traverses the switch to the router.Tip: If you are using Power over Ethernet (PoE) switches to power your VOIP phones, Ubiquiti's UniFi switches handle this natively. VOIP phones draw 5-15W each via PoE, eliminating the need for separate power adapters on every desk. A US-8-60W can power up to 4 phones, or a US-16-150W for larger deployments.

Other Common Routers

DrayTek Vigor (2862, 2927, 3910 series): Popular in AU SMB environments. QoS is under Bandwidth Management > Quality of Service. Create a class for VOIP (match by DSCP or port), assign to Class 1 (highest priority). DrayTek has excellent QoS granularity and is one of the better choices for business VOIP.MikroTik: Powerful but complex. QoS is configured via queue trees and mangle rules in RouterOS. Unless you or your IT consultant is comfortable with MikroTik, choose a router with a GUI-based QoS interface for VOIP. Misconfigured MikroTik QoS can make things worse.ISP-supplied modems (Netcomm, Sagemcom, Arris): Most ISP-supplied modems have minimal or no QoS capability. If you are running VOIP on an ISP modem, the recommended approach is to put the modem in bridge mode and use a dedicated router behind it for QoS.

NBN Connection Types and QoS Effectiveness

Your NBN connection type affects how much benefit QoS provides. This is because different connection types have different buffering characteristics and congestion profiles. If you are on FTTN or HFC and running VOIP, QoS should be considered mandatory rather than optional. These connection types have the tightest upload bandwidth and the most variable performance, which is exactly where QoS makes the biggest difference.

Bridge Mode: Why Business VOIP Often Needs a Separate Router

If you are running your VOIP phones directly behind an ISP-supplied modem, you may be limited by the modem's QoS capabilities (or lack thereof). The solution is bridge mode.In bridge mode, the ISP modem acts only as a media converter. It handles the physical connection to the NBN network but passes all routing decisions to your own router behind it. Your router then handles NAT, firewall, DHCP, and QoS.This gives you full control over QoS configuration and eliminates the double-NAT issues that can cause SIP registration problems (where calls connect but audio is one-way or drops after 30 seconds). Most NBN ISP modems support bridge mode, though the process varies. Check your ISP's support documentation or call their technical support line.Important: Before switching to bridge mode, confirm that your ISP modem is not providing other services you rely on. The Telstra Smart Modem, for example, includes 4G backup and a built-in home phone ATA port. Bridge mode disables these features. Make sure you have alternatives in place before switching.

VLAN Separation: The Professional Approach

For businesses with more than a handful of VOIP phones, the professional approach is to put voice traffic on a separate VLAN (Virtual LAN). This keeps voice packets physically separated from data traffic at the switch level, before they even reach the router.With a voice VLAN, your VOIP phones connect to switch ports assigned to VLAN 100 (for example), and your computers connect to ports on VLAN 1 (default). The two networks are isolated. Voice traffic never competes with data traffic at the switch level. QoS on the router then handles the final prioritisation at the WAN link.VLAN setup requires a managed switch (not the unmanaged 8-port switch from Officeworks). A Ubiquiti US-8-60W (~$200 AUD), TP-Link TL-SG2008P (~$120 AUD), or Netgear GS308EPP (~$130 AUD) will handle this. If your VOIP provider or an IT consultant is setting up your system, ask them to configure voice VLANs. It takes 15 minutes during initial setup and eliminates an entire category of quality issues.

Troubleshooting: QoS Is Configured but Calls Still Sound Bad

If you have configured QoS and call quality has not improved, work through this checklist.Check that QoS rules are matching traffic. Most routers have a QoS statistics or monitoring page that shows how much traffic is being classified into each queue. If the voice queue shows zero bytes, your rules are not matching. Verify port numbers, DSCP values, or device IPs in your rules.Check for DSCP stripping. Some ISP modems and even some routers reset DSCP markings to 0 on outbound traffic. Use a packet capture tool (Wireshark on a mirrored switch port) to verify that DSCP 46 is present on packets leaving your router's WAN interface. If it is being stripped, switch to port-based QoS rules instead of DSCP-based.Check your bandwidth limits. If you set your QoS upload speed to 50 Mbps but your actual upload is 18 Mbps, the QoS engine does not know the real limit and cannot manage the queue effectively. Always use measured speeds, not plan speeds. Run a speed test during business hours for the most realistic number.Check for WiFi phones. If any VOIP devices are on WiFi rather than wired Ethernet, QoS on the router cannot help with the WiFi hop. WiFi introduces variable latency that is outside the router's QoS control. Move VOIP phones to wired connections.Check for upstream issues. Run a continuous ping to your VOIP provider's SIP server (your provider can give you the address) for 10 minutes. If you see packet loss or latency spikes in the ping results, the problem is between your router and the provider, not within your local network. QoS cannot fix this. Contact your ISP or consider a secondary WAN link as failover.Check SIP ALG. Many routers have a feature called SIP ALG (Application Layer Gateway) that is supposed to help VOIP traffic traverse NAT. In practice, SIP ALG causes more problems than it solves, including one-way audio, dropped calls, and registration failures. Disable SIP ALG on your router. This is found under advanced settings or firewall settings on most routers.

What Most Businesses Get Wrong

Mistake 1: Configuring QoS When the Problem Is Elsewhere

QoS is the go-to recommendation in every VOIP troubleshooting forum. But it only solves local congestion. If your calls are bad because your FTTN copper line is degraded, because your ISP is oversubscribed at the POI, or because your VOIP phones are on WiFi, QoS will not help. Diagnose first, configure second. Run a bandwidth check, test ping latency to your provider, and confirm phones are on wired Ethernet before touching QoS.

Mistake 2: Leaving SIP ALG Enabled

SIP ALG is enabled by default on most consumer and many business routers. It rewrites SIP packet headers as they pass through NAT, and it frequently gets it wrong. The result: one-way audio (you can hear them but they cannot hear you), calls dropping after exactly 30 seconds, or registration failures where phones intermittently go offline. Disabling SIP ALG fixes more VOIP problems than QoS does. It should be the first setting you change on any router used for VOIP.

Mistake 3: Setting QoS Bandwidth to Plan Speed Instead of Measured Speed

Your NBN plan says 50/20 Mbps. Your actual measured speed is 42/17 Mbps. If you configure QoS with 50/20, the QoS engine thinks it has 3 Mbps of upload headroom that does not exist. The queue overflows before QoS kicks in, and voice packets get dropped. Always set QoS bandwidth limits to 85-90% of your actual measured speed, tested during business hours when the connection is under real load.

Your Next Steps

Here is the practical checklist for configuring QoS for VOIP on your network.1. Test your baseline. Before changing anything, run a speed test during business hours and note your actual upload and download speeds. Make a VOIP call while someone runs a large download. Note whether call quality degrades. If it does not, you may not need QoS at all.2. Disable SIP ALG. Log into your router, find SIP ALG (usually under firewall, NAT, or advanced settings), and turn it off. Restart the router. This alone fixes a significant percentage of VOIP issues.3. Move VOIP phones to wired Ethernet. If any phones are on WiFi, switch them to wired connections. No amount of QoS configuration can compensate for WiFi variability.4. Configure QoS on your router. Follow the steps for your specific router above. Set bandwidth limits to 85-90% of measured speeds. Create a high-priority rule for VOIP traffic (DSCP 46 or UDP ports 5060 and 10000-20000).5. Test again. Repeat the stress test. Make a call while running a large download. If call quality stays clear, QoS is working. If it still degrades, check for DSCP stripping, verify your rules are matching traffic, and consider bridge mode if you are behind an ISP modem.6. Consider a dedicated router if on ISP modem. If your ISP modem does not support QoS properly, put it in bridge mode and add a business-grade router. A Ubiquiti ER-X (~$90 AUD), TP-Link ER605 (~$100 AUD), or DrayTek Vigor 2927 (~$500 AUD) will handle QoS properly and give you control over your network.

What is QoS and why does it matter for VOIP?

QoS (Quality of Service) is a router feature that prioritises certain types of network traffic over others. For VOIP, it ensures voice packets are sent before other traffic like file downloads or video streaming. This reduces latency, jitter, and packet loss during calls, keeping audio clear even when the network is busy.

Does every NBN router support QoS?

No. Many ISP-supplied modems have limited or no QoS capability. Consumer routers usually have basic QoS (device priority or port-based rules). Business-grade routers from Ubiquiti, DrayTek, TP-Link Omada, and MikroTik have full QoS with DSCP-based classification. If your router does not support QoS, consider putting your ISP modem in bridge mode and adding a dedicated router.

What DSCP value should I use for VOIP traffic?

DSCP 46 (Expedited Forwarding/EF) is the standard for voice media (RTP audio packets). Most VOIP phones and softphones mark their audio packets with DSCP 46 by default. SIP signalling traffic typically uses DSCP 24 (CS3) or DSCP 26 (AF31). Configure your router to give DSCP 46 packets the highest priority.

Should I put my Telstra Smart Modem in bridge mode for VOIP?

If you have more than 3-4 VOIP phones or are experiencing call quality issues, bridge mode with a dedicated router behind the Telstra modem is recommended. The Telstra Smart Modem has limited QoS capability and some firmware versions strip DSCP markings. Bridge mode gives you full control over QoS and eliminates double-NAT issues. Note that bridge mode disables the modem's 4G backup and built-in phone port.

Will QoS slow down my internet for other users?

Only when the connection is congested and voice traffic is active. When a VOIP call is happening during heavy network usage, QoS will slightly reduce available bandwidth for downloads, streaming, and other traffic to protect call quality. When no calls are active, all bandwidth is available normally. The impact is typically imperceptible because voice traffic uses very little bandwidth (about 100 Kbps per call).

What is SIP ALG and should I disable it?

SIP ALG (Application Layer Gateway) is a router feature that modifies SIP packets as they pass through NAT. It is intended to help VOIP work behind NAT, but in practice it frequently causes one-way audio, dropped calls, and registration failures. Disable SIP ALG on any router used for VOIP. It is enabled by default on most routers and is found under firewall, NAT, or advanced settings.

How do I know if QoS is actually working?

The simplest test: make a VOIP call and simultaneously start a large file upload or download. If the call stays clear while the transfer slows down, QoS is working. Most routers also have a QoS statistics page showing traffic classified into each priority queue. If the voice queue shows traffic during calls, your rules are matching correctly.