ETHERNET AND TOKEN RING TOPOLOGY
There is no 'converter' that allows an Ethernet network and Token Ring network to communicate between each other. A conversion process must occur between the two topologies, since they both use different signaling types, frame structures, and frame sizes.
There are two methods to accomplish this 'conversion'; bridging, and routing. Bridging Bridging is a method of communicating between devices at OSI layer 2, the data link layer. A bridge connects two networks together and acts as a traffic director. If traffic is destined to the other network, the bridge allows the traffic to pass.
If the traffic is local to a single network, the bridge does not pass the traffic unnecessarily to the other connected network.
The bridge keeps an updated list of everyone active on the network, and uses this list to direct traffic from one network to another. This method of operation makes the network appear as a single logical network, since the only separation of traffic from one network to another is done at the MAC address level. There are many bridge manufacturers and bridge types on the market.
These switches have a much higher port density than the older two or three port bridges, allowing for much more flexibility and network segmentation. Routing The second method of 'converting' from Ethernet to Token Ring is called routing.
Routing occurs at OSI layer 3, and separates physical networks into separate logical networks. This differentiates routing from bridging, since bridging maintains a single logical network. In a routed network, the sending workstation determines if outgoing traffic is local or remote.
If the traffic belongs to another network, the originating station sends the frame directly to the router for further processing. Upon receiving the frame from the source workstation, the router examines the frame for the destination address.
The router maintains a routing table which is used to determine the final destination of the data packet through the router. Routing is the most common method of connecting Ethernet networks to Token Ring networks in most organizations.
Most network operating systems have routing capabilities built into the servers. By placing a token ring and Ethernet card into a Novell NetWare 3.
One caveat; some protocols are not routeable. Protocols which cannot be routed must be bridged between physical networks. My Books.