Planning for network performance

You can have fast servers and workstations, but if the data traffic between them is slow, the whole enterprise is slow. Therefore, it is important to plan your network bandwidth to match the speed of your business.

You can improve performance by:
Before you begin
__ Highlight areas of your network topology where potential bottlenecks may occur.
__ Identify network traffic that should be given the highest priority.
Network performance planning tasks
__ Plan to remove bottlenecks
You need to identify areas where network traffic is greater than the bandwidth that it is flowing through. Start by examining the topology and identifying potential slow areas, and then monitor those areas. After you identify slow areas, or bottlenecks, plan to upgrade hardware and improve performance. Possible problem areas include:
  • Older Ethernet network cards

    If your Ethernet network interface cards (NICs) are 10BASE-T, they can be easily upgraded to Fast Ethernet. In -critical networks, you can upgrade Ethernet to Fiber Distributed Digital Interface (FDDI).

  • Hubs instead of switches

    Hubs send data to all participants that are connected to them. Switches send data only to its desired destination. If a hub is connected to three hosts, a switch will typically be three times faster than that hub. If tens of hosts are connected to a hub, then the switch speeds performance.

  • Overloaded routers

    Routers can significantly slow traffic if more hosts are connected to them than they can reasonably handle. You can either upgrade upgrading the router or convert to a smart switch.

  • Too many routers

    You may try to fix overloaded routers by adding more subnets and connecting them with more small routers. This can make your situation worse by increasing the number of hops that data must travel through to get to its destination. It is often better to upgrade the router than to add hops to the network.

  • Outdated servers

    Some network administrators put older servers on the front end because the data flow is not as critical as it is in the back end. But, older servers might not be able to keep up with graphics-intensive user applications, such as Flash programs that run over the Web, and users may become frustrated by waiting for applications to load.

To learn more about how to improve network performance, see the chapter on multicasting and quality of service in the IP Network Design Guide.Link to a PDF
__ Plan for multicasting

Multicasting sends data from the server to multiple clients at one time. In one-to-one networking, the total bandwidth that is required equals the bandwidth that is needed by the application times the number of clients. With multicasting, the total bandwidth that is required only equals the amount of bandwidth that is needed by the application. Multicasting only works with "push" applications, such as online newsletters. If you can convert some of your one-to-one applications to multicasting, you can conserve network bandwidth and improve performance. However, setting up the network to handle multicast traffic involves designing the entire network topology with multicasting in mind.

__ Plan for QoS

QoS works like the high-occupancy commuting lanes that are on highways. Special lanes are set up for traffic, vehicles with two or more passengers per car, so they can arrive at their destinations faster by not getting stuck in traffic in the slower lanes. Similarly, with QoS, the network gives priority to certain data packets and ensures that they arrive at their destinations within a certain time frame. Like multicasting, planning for QoS must include the entire network topology. If you plan to implement QoS, review the network software and hardware planning steps and incorporate prioritized traffic protocols throughout your topology.

When you have completed these tasks, you should have a network performance plan that identifies these elements:

After you finish
__ Identify the nodes of your network topology that need performance-related equipment upgrades.
__ If you plan to multicast, record a list of hardware and software that enables multicasting.
__ If you plan to use QoS, record a list of hardware and software that enables QoS.