thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Routing & Switching · Foundational

Voice QoS Requirements

Guidelines for acceptable voice quality: one-way delay under 150 ms, jitter under 30 ms and packet loss under 1 percent.

Definition

These figures come from ITU-T G.114 and Cisco design guidance. Voice bearer traffic is small and constant (for G.711 about 80-90 kbps per call with overhead), so it needs priority treatment rather than large bandwidth. Interactive video tolerates similar delay but needs more bandwidth.

Example

Provision an LLQ class sized for 20 concurrent G.711 calls.

Exam tip

Memorize 150 ms / 30 ms / 1 percent; they appear frequently.

Related terms