Wi-Fi mesh networks suitable for VoIP services (1)

With the rapid development of wireless mesh networks, new public or private wireless networks are deployed almost every day.

When multiple hops are used in a Wi-Fi mesh to cover a wide range of areas, a series of problems may occur, such as bandwidth decrease, wireless interference, and network latency. These problems seriously impair the provision of real-time services, such as the VoIP service that Wi-Fi providers most want to provide. The multi-modular design, multi-RF, and multi-channel Wi-Fi-Fimesh network can solve all of the above problems and provide a real high-performance Wi-Fi network to optimize real-time services such as voice.

Although Wi-Fi has already clarified the network topology of its data application, some internal problems need to be solved when deploying wireless VoIP (wVoIP. The Wi-Fimesh network solves the problem of Wi-Fi, which makes the planning, deployment and operation more cost-effective, especially in environments that are hard to achieve by cable (tens of square kilometers require hundreds of cable fiber nodes, which is not economical ).

I. mesh network requirements

StrixSystems believes that the mesh network architecture must be able to deliver high throughput, low latency, and end-to-end QoS. These requirements are not only between the wireless terminal and the access point, but also include the entire mesh link until the wired endpoint. Therefore, the mesh backbone network must meet the following four requirements.

1. multi-hop high throughput

Regardless of the number of hops on the mesh (usually between 3 and 10), the mesh backbone network must still support traffic load. The ability to support high throughput is directly equivalent to the number of speech and data users that the system can provide. Insufficient bandwidth after multiple hops will lead to unsatisfactory user density, and additional devices and more wired endpoints are required in the network.

2. Low latency with multiple hops

To avoid jitters, the packet delay of each hop must be minimized. The group package stays on any node in the mesh network for the shortest time, achieving the same performance as the wired network. Therefore, in an ideal situation, the packet should be forwarded before the previous node receives all the information.

3. End-to-End QoS is the priority of the voice packet grouping.

In order to solve the conflict between load traffic, the speech must be given priority in the mesh backbone and ended on the switch with the traffic priority processing capability. Assigning priority for voice must be automatic and can be handled through VLAN/SSID. In the short term, you cannot count too much on 802.11e. It is far from enough to provide a service level between a wireless terminal and an AP. Mesh imposes QoS requirements on the entire backbone network to avoid conflicts between each hop in the mesh.

4. Layer2 Switching Network

A roaming problem occurs in the Layer3 network, while the Layer2 network minimizes the problem. Layer3 networks also require careful planning of different high-level protocols. These two points will cause performance and installation problems.

Any of the above four factors will directly affect Scalability (based on the number of users and network coverage) and speech quality. If the multi-hop topology cannot meet these requirements, it lacks the speech support capability.