IBM SG24-4817-00 manual Internal Features, ATM Cell Switching in the IBM 8285 Base Unit

This soft copy for use by IBM employees only.

Note

Although there are two models of the 8285 switch, the 8285-00B and the 8285-00P, they are identical except that the latter includes 12 workstation adapters, providing a total solution at a special bundled price.

2.2 Base Unit

The base unit is comprised of the following:

•Internal Features:

−An ATM cell switching function

−A switch control function, called the 8285 ATM Control Point

•Front Panel Features:

−Ports:

-12 ATM ports that support ATM 25.6 Mbps operation over standard copper wiring

-A slot for an optional high-speed uplink to provide 155 Mbps access to either a server or to an ATM backbone

−LEDs:

-System Status

-Port Status

−Connectors:

-A connector to connect the optional expansion unit

-A connector to connect a standard ASCII console

2.2.1Internal Features

The IBM 8285 Base Unit contains a planar which controls the 8285 switch and its external interfaces.

2.2.1.1 ATM Cell Switching in the IBM 8285 Base Unit

The ATM switching mechanism installed in the base only switches ATM cells between ports in the base unit. This is accomplished by basically taking what would normally be the backplane output and connecting it directly to what would normally be the backplane input.

When an IBM 8285 Expansion Chassis is connected to the IBM 8285 Base Unit, however, this connection is disabled, and the traffic from the IBM 8285 Base Unit uses the switch-on-a-chip that is incorporated in the IBM 8285 Expansion Chassis.

2.2.1.2 8285 ATM Control Point

The 8285 ATM Control Point is integrated in the base unit and provides the following functions:

•Manages the functions of the IBM 8285 Base Unit as well as the optional 8285 Expansion Chassis and its inserted modules.

10ATM Workgroup Solutions: Implementing the 8285 ATM Switch