Quality of Service
Quality of Service (QoS) is a concept that proposes that some network services deserve better bandwidth, lower latency, fewer errors, and stability than others. These differences in network services become apparent when you compare data traffic and traffic produced between two recipients using VoIP. When data traffic passes through the network, it either succeeds or fails (and can be re-sent). However, when VoIP traffic passes through the network, it is carrying data that comes from human speech and the integrity of this speech must be preserved.
Users have a very low tolerance for poor quality phone calls and dropped audio. Real-time applications such as voice and video are more susceptible to customer complaints than any other traffic. It is essential that QoS is correctly implemented in conjunction with a VoIP telephony solution.
It is rarely practical to install dedicated network infrastructure for VoIP except perhaps in the smallest of networks – i.e. an 8-port PoE switch. Even so, VoIP must be prioritised if the Internet link is shared.
Basic Recommendations (for SME networks)
- Use good quality, fully-managed PoE switches
- Implement VLANs, e.g. Voice, Data, Video (IP CCTV or IPTV)
- Some switches include pre-configured Voice VLANs with low latency.
- Use Link Layer Discovery Protocol (LLDP) to automatically configure VoIP phones with VLAN and QoS.
- Classify local traffic not already handled by LLDP (i.e traffic from IP-PBX or VoIP Gateway)
- Classify incoming VoIP traffic from any upstream service providers and prioritise it.
- Avoid daisy-chaining PCs into VoIP phones if possible; if you must:
- Use phones with Gigabit network ports.
- Ensure that the phone ‘data’ port has the appropriate QoS setting (phone provisioning)
- Implement traffic shaping (bandwidth management) on the Internet router/firewall.
- Contact us if you have more complex requirements and we will help you.
How can EFL help?
Electronic Frontier Ltd (EFL) is a value-added distributor specialising in converged IP solutions.
We can help you create a complete & fully supported VoIP solution (with QoS!) by recommending products from our interop-tested portfolio.
Benefit from a single point of contact for supply & support.
We represent, amongst others:
3CX | beroNet | Mediatrix | Patton | snom | Yealink | ZyXEL
Did you know we also supply IP CCTV solutions?
