VoIP Performance Optimization

Traditional data networks cannot support real-time voice quality and network performance requirements technically. However, the current network technology advances, such as the new traffic priority division and bandwidth management tools, can completely establish an efficient speech data convergence network.

The biggest challenge to implementing VoIP is the design and construction of an IP network that meets the strictest QoS requirements and the performance comparability with commonly used circuit switched telephone networks. To ensure continuous and reliable VoIP traffic, the network must support four capabilities: high performance, low latency jitter, line protection, and QoS, these four aspects ensure real-time transmission of VoIP packets over the network.

The layer-3 Switching Device of Extreme has policy-based QoS capabilities, which can precisely guarantee the two-way minimum or maximum bandwidth for different types of data streams, and provide ideal support for VoIP by minimizing latency and jitter. Policies are a series of advanced rules that determine how to allocate network resources to applications. The process of establishing a QoS policy first identifies the data stream and defines the corresponding QoS service levels for different data streams and prepares them as files. In this way, even when the network is congested, you can also ensure complete and real-time delivery of VoIP streams for key tasks. Bidirectional rate shaping and DiffServ are unique traffic management and bandwidth priority management tools provided by Extreme "I" Exchange chips. They also support VoIP traffic. Bandwidth management is implemented based on DiffServ encoding points. Each port has eight hardware queues. The minimum and maximum bandwidth parameters of each queue can be mapped to the DiffServ encoding point, to provide speed assurance and speed shaping.

VoIP performance optimization requires several capabilities, such as the ability to flexibly classify conversation audio services to ensure minimum bandwidth settings, it provides excellent QoS Assurance capabilities for other service categories on the network and real multi-service support capabilities. IP technology-based telephone technology should be used in enterprise networks. VoIP VLAN is an ideal method. The IP Phone VLAN should be a tagged VLAN with a specific 802.1Q vlan id for VoIP. If the VoIP and desktop PC share the switch port, the specific port must also be a VLAN member compatible with the PC.

Minimum bandwidth settings-a Summit 48 switch that supports 48 IP phones requires a minimum value of 4 Mbps on the downlink to support 48 concurrent calls; when 200 IP phones are connected to an Alpine switch, a minimum downlink bandwidth parameter of 16 Mbps is required. This calculation of potential peak bandwidth needs should be done at least at the network edge and core layer.

Read/write capability for 802.1p and DiffServ encoding point-by configuring, you can add the ideal 802.1p or encoding point value to a data packet or when the data packet leaves the switch, thus, the downstream switches that cannot distinguish voice business flows maintain the "End-to-End" QoS connection required by the business.