Cabletron Systems bridges Manuel D’Utilisation

The Workgroup Approach

3-6

Stackables

HubSTACK Interconnect Cables are connected in a particular sequence, from the 
OUT port of the first device in the stack to the IN port of the next. This 
arrangement is repeated from device to device as more stackable hubs are 
incorporated in the stack, as shown in Figure 3-3. 

Once stackables became accepted in networks, users demanded management for 
them. The response from manufacturers was to make intelligent stackable 
devices. The design of intelligence and management capabilities for the stackable 
devices followed a path similar to the incorporation of management into modular 
chassis. Rather than requiring that all the stackables in a stack be intelligent in 
order for management functions to be performed, stackable intelligence is 
contained in only one device and is extended to the non-intelligent devices in the 
stack. Thus, only one intelligent device is needed to manage a full stack, keeping 
the costs of management down.

The basis of the intelligent stack is that the first device in each stack is the only one 
that requires this management intelligence. This intelligent stackable, or base, 
provides management services for the rest of the devices in its stack over the same 
connection that is used for stackable to stackable communications. The 
management traffic moves across the artificial backplane that is set up through 
the interconnect cables.

As stackable devices and stacks are easy to design and configure, and often have a 
lower cost than modular networking chassis for these small-scale, simplistic 
network implementations, they are often found in large enterprise networks 
acting as fringe devices. These devices operate at the frontier areas of the network, 
where users connect to small shared network segments.

The use of stackable devices in these frontier workgroup environments often 
necessitates the use of a differing network technology, such as Fiber Distributed 
Data Interface (FDDI) or Asynchronous Transfer Mode (ATM) to make 
high-bandwidth connections to the enterprise network backbone or a central 
campus switch. The basic design of stackable hubs does not allow for the 
incorporation of different network technologies as does a modular networking 
chassis such as the Cabletron Systems Multi-Media Access Center, or MMAC.

If it becomes necessary to disconnect a HubSTACK 
Interconnect Cable from a device in the stack, disconnect the 
cable at the OUT port of the previous device in the stack to 
ensure proper termination of the Interconnect Cable chain.