IBM SG24-4817-00 manual Stand-Alone Token-Ring Migration

This soft copy for use by IBM employees only.

Note

If the module is configured for source route switching, all token-ring LAN ports and emulated token-ring LAN ports share the same ring number.

4.9.2 Sample Scenarios

The 8285 LAN switching modules complement the IBM 8285 Base Unit′ s cost-effective ATM25 capabilities and can serve as the basis for a smooth migration from traditional shared-media LANs to the high-performance ATM networks of the future. Here are some scenarios that could be implemented.

4.9.2.1 Stand-Alone Token-Ring Migration

In this scenario, a workgroup of 80 users and 4 servers has run out of bandwidth on its local token-ring network. A very simple way to alleviate this constraint is to implement an 8285 switch with a 3-slot 8272 ATM/LAN Switch Module right in the same wiring closet, as illustrated in Figure 30.

Figure 30. Relieving Token-Ring Congestion with LAN Switching Module

The first change to make is to move all four servers off of the common ring and give them dedicated bandwidth. If we use full-duplex token-ring adapters, such as the IBM Auto LANStreamer MC32 Adapter or the IBM Auto LANStreamer PCI Adapter, we can enable the servers for full-duplex operation, connect them to a LAN switch port, and let the LAN switch module automatically provide each server with 32 Mbps of dedicated bandwidth.

In addition, if we choose we can take advantage of the 8285 switch′s 155 Mbps ATM port by installing a high-performance ATM adapter, such as the IBM Turboways 155 Mbps adapter, in our most heavily used server.

Chapter 4. IBM 8285 ATM Modules 77