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How do I set QoS / DiffServ for VoIP?

Mark voice packets DSCP EF (46), switches and router must honour it.

Try this first

  1. 1On SIP phone or softphone set DSCP EF (46) for RTP
  2. 2Switch trust mode on DSCP, do not remark
  3. 3Router QoS policy: voice class priority with low-latency queue
  4. 4WAN: reserve 100 kbit/s per simultaneous call

When to bring us in

No QoS available on WAN? Second line or SD-WAN with guaranteed voice class.

See also

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