Migrating Token Ring to Ethernet

Many Token Ring users contemplate a migration from Token Ring to Ethernet. In some cases, the motivation is the available bandwidth of Fast Ethernet. Sometimes the motivation is to simplify cabling. But moving an infrastructure from Token Ring to Ethernet involves several considerations. For example, the media cabling type might differ. Many Token Ring systems utilize Category 3 cable (shielded twisted-pair), whereas Ethernet typically uses Category 5 cable (unshielded twisted-pair). Other elements to consider include changing workstations' adapters along with their drivers, performance requirements for existing protocols, and application demands.

A migration plan usually involves phases rather than a comprehensive one-time changeover. Cost, labor availability, and risk drive a migration plan to spread over time. But what should change first? Clients? Servers? Departments? If the cabling infrastructure needs to be upgraded to support the new Ethernet system, the migration may possibly involve geographical issues. This means that the network will change one room or one floor at a time.

If the primary concern is to minimize risk, the migration plan might be a hierarchical approach. Start by moving the backbone to a Fast Ethernet, and bridge or route between the backbone and the distribution segments. Then as the technology proves itself for the applications, move selected devices, such as servers, to the Ethernet system.

Whatever approach you take, be sure to plan it. Migrate don't mutate the network.