Network Setup for Best VoIP Installations
Best Network Practices for Good VoIP Quality
Tips for when you change to Voice over Internet Protocol.
VoIP quality can easily denigrate if network conditions are not suited for voice
(VoIP). For this reason
it is best to follow some good basic network design when it comes to your LAN
(Local Network Area). The following
suggestions can work well for a stable VoIP deployment, whether at home or
with your small business. Networks may not see any significant issues
with general data flow until VoIP is added to the equation. For this reason
and knowing that more applications are moving to the cloud, a general
assessment of your network would be in order. Start with general conditions and age of
equipment reviewing the need for replacement of older routers, switches and modems. Then continue with each
segment of the LAN so that there are no bottlenecks where voice can become delayed.
More small companies are moving their applications to the cloud. VoIP is one such service. Upgrading your network
will prevent problems.
- Make sure all cabling infrastructure is adequate and in good condition.
- Segregate a switched 100BaseT LAN with a dedicated cable for voice if
- Using Gigabit Ethernet for connections from routers to switches and switches to switches.
- Use good quality late model IP phones with each phone having a switch port integrated switch that can
prioritize voice over data packets, if the users will share one cable with the PC.
- Ensure that adequate bandwidth exists with your Internet service provider for both the upload and
download and that no packet loss exists on the WAN network. Test your Internet connection for packet loss
and latency and make sure that signal levels for cable modem connections and DSL are in spec.
- Upgrade older cable modems and/or DSL modems to later models. Ensure
the latest firmware is installed.
- Choose a router(s) that allows for prioritization of RTP and SIP traffic (QoS) and
firewalls that are SIP/VoIP friendly.
- You may want to set up a virtual LAN (VLAN) for the VoIP devices as a guarantee they get the bandwidth
- As more applications are moved to the cloud, look into a SD-WAN
appliance to better manage services.
How much bandwidth will you need?
When considering VoIP bandwidth requirements you can be easily calculate your needs by using the round number of
100kbps (for a G711 non-compressed codec) for both the inbound and outbound voice. Except for T1s (and possibly
some types of DSL connections) most provider's Internet connections are asynchronous, meaning the download bandwidths
are much greater than the upload.
Good Internet service has both come down in cost and increased in stability. Cable companies are competing
for small business accounts with excellent packages which is one big reason cloud based services are growing so robustly.
Voice connections travel both ways, so pay more attention to uploads
which can be a deciding factor.
- Take the amount of phone connections times 100kpbs for a good approximation of just your voice needs.
The actual usage will be ongoing concurrent calls. So, 5 calls times 100kpbs would require 500kpps for both
the upload and download.
- Compressed codecs like G729 would only require roughly 40kpbs per call for both outbound and inbound.
- When considering bandwidth needs, companies that use applications large bandwidth needs, like CAD,
large file downloads, etc., need to calculate these needs in the overall bandwidth.