Replacing All Token-Ring Equipment | Upgrading and Repairing Networks (5th Edition)

In a small LAN, swapping out all the Token-Ring hardware and replacing it with Ethernet equipment might be feasible . If you carefully plan the implementation around users' work schedules, you can minimize disruptions on the network. Before beginning, you should inventory the existing equipment to see what must be replaced and what, if any of it, can be retained.

For the most part, however, you'll likely find yourself replacing the cabling from the desktop to the wiring closet, older routers, multi-station access units (MAUs and MSAUs), and other connectivity equipment. Some of your infrastructure may be salvageable, however. For example, the backbone wiring of your network may be adaptable to the new topology of your network. Similarly, other parts of your current network may not be sufficient for an Ethernet network. For example, if Token-Ring MAUs are distributed throughout an office instead of being situated in a wiring closet, you may have to run new cables from a wiring closet to each desktop. Recabling a network can be both time-consuming and expensive.

Each situation will require a good inventorying of existing equipment to see how it fits into an overall plan.

Tip

Another possibility to think about is using wireless networking for small islands of users where stringing cables to the desktop may be very expensive. Section V, "Wireless Networking Protocols," is worth reading if you are interested in learning whether wireless networking is appropriate for part or all of your network.

Switches and Routers

Some of the newer routers and switches that have come onto the market in the past few years have the capability to operate with either Ethernet or Token-Ring networks. If you are contemplating a change-over in the near future, this should be a consideration when you're making any current purchases. Buying a more expensive device now, that you can use now and still use when you upgrade the network in the near future, can save you money in the long run.

If you have been using a gradually phased approach for your upgrade (that is, you are upgrading in small chunks ), the router or switch that is currently operating as a translation device might easily be reconfigured to work just fine in an all-Ethernet network. Read the documentation for each device to determine what steps need to be taken. If you cannot find the information readily available in the documentation that came with the equipment, check with the manufacturer. Many times a simple download of a new version of the device's firmware can solve this kind of problem.

Network Cabling and Connectors

Most new installations of network cabling are of the Category 5 (or better) twisted-pair type. This cable can support ordinary Token-Ring 4MB or 16MB networks as well as Ethernet networks running at speeds from 10Mbps to 100Mbps with no problems. You will need to consult your network map to be sure that any existing cabling infrastructure for the LAN does not violate any of the distance or nodes-per-segment rules that apply to Ethernet. If the existing cables have been installed for quite some time and are of a grade not equal to Category 5, you should probably replace them.

The connectors used for Token-Ring and Ethernet may be different on your network. Ethernet networks based on 10BASE-T or 100BASE-T typically use an RJ-45 connector. Although this kind of connector also can be used on a Token-Ring network, the wires used and the pins to which they are attached on each end will be different from the pin-out used on Ethernet networks. Changing these requires time for making the actual physical wire-to-pin changes. Additionally, even more time is needed for testing the cable to be sure that the connectors have been properly installed and will function with a minimum of errors on the new network.

Network Adapter Cards

Token-Ring and Ethernet network adapter cards are different at a very basic level and are not compatible. Token-Ring NICs usually cost much more than Ethernet cards. One of the reasons is that Token-Ring NICs take on more responsibility for managing transmission of data on the local LAN than Ethernet cards do. Remember that Token-Ring cards wait for a token before transmitting data. Ethernet cards can just start talking any time they sense that the network media is free. When making a change-over, it will be necessary to acquire a new card for each end- user workstation, as well as for any servers on the network.