Quality of Service (QoS) refers to the prioritization of traffic throughout a network. In the context of your Intulse services, this term refers to giving priority to voice and video transmissions over other traffic types like general internet browsing or file transfers. Particularly in scenarios where bandwidth is limited, properly configured QoS is crucial if maximum call quality is to be obtained. Properly implemented, QoS can reduce congestion, latency, and packet loss—all of which negatively impact call quality.
There are several different ways to implement QoS, and network admins should use the option that best fits their network environment. The strategies discussed below pertain to traffic inside a Local Area Network (LAN) and between the hand-off from a LAN to a Wide Area Network (WAN). Any QoS set up on a WAN connection itself must be configured by your internet service provider (ISP).
A popular way to ensure network quality is to physically separate voice and data networks. This method involves using a dedicated WAN connection for voice only, and using separate WAN connections for data traffic.
Another method for achieving QoS on a LAN is logical network separation. Networks can be separated into logical divisions or Virtual Area Networks (VLANs) to separate voice from lower priority traffic. This traffic balancing, or policy-based routing, can allocate bandwidth dynamically based on volume, or statically by manual assignment.
If you have multiple WAN connections you can configure your network to route your voice VLAN out one WAN connection and all other VLANs over another. In this scenario, saturation of the "data" WAN connection is irrelevant, as all voice traffic is routed over its own WAN connection.
Routers and gateways can be configured to honor Layer 3 DSCP values. Layer 2 802.1p/CoS values can also be used, though DSCP is preferred.
On higher-end LAN equipment, proper QoS policies can be verified by watching the traffic flows and/or queues. If this is not possible, a handful of empirical tests can also be used:
It is usually recommended, but whether or not it is needed depends on the nature of your network and how likely you are to saturate bandwidth on any one of your links.
The best way to implement QoS is to implement as many of the following as possible:
Port prioritization is not recommended because it will be a random port between 20,000 – 60,000. If this is your only method to implement QoS, it is best to purchase a new router.