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Magnum 3000 Stackable HubsInstallation and User Guide (07/06)

The IRB ribbon cables supplied with each Magnum 3000 base unit are slightly longer than the base unit height. Thus, an IRB cable segment has a small arc shape when it is properly installed. It is possible to have some long IRB ribbon cable segments, up to a few meters in length, for service loops and such. The operation of the stack will not be impaired by longer IRB ribbon cables. Stacks with total IRB lengths of as much as ten meters can be implemented. However, non-standard IRB cable lengths must be specially made.

The IRB ribbon cables may be installed and/or removed while a Magnum 3000 unit is powered without causing damage to the electronic circuits in that unit or any others in a Magnum 3000 stack. This is convenient for expanding a stack without shutting down the network, and for performing diagnostics and service on potentially faulty units operating in a stack. CAUTION: disconnecting an IRB ribbon cable can cause operational upsets by breaking the interconnection among the stacked units previously operating as a single repeater and/or with one SNMP agent.

2.3.2Segmenting a Magnum 3000 Stack with a Special Segmenting

Cable

Magnum 3000 Stackable Hubs are typically stacked as described in Section

2.3.1.However, it may be desirable to stack the 3000s so that they operate as separate repeater units. This will normally be done to manage several separate hubs (or small stacks) with a single 3000 AGT SNMP Agent box. In this situation, single units or several small stacks of units may be connected using SRC Segmenting Cables (part numbers SRC-2 and SRC-4, available as a spare part from GCI). Hubs connected via an IRB Segmenting Cable do not transmit or receive normal Ethernet traffic through the IRB.

GCI supports this non-standard configuration, making special stacking cable available (see Models SRC-2 and SRC-4 in the Spare Parts Price List) to provide the flexibility to break apart managed stacks into multiple collision domains for higher performance, while still maintaining the advantages of one SNMP agent.

Consider the case where it is desired to divide a managed stack into two segments and insert a local bridge to increase performance (see Figure 2.3.2a).

Normally, it would be necessary to add another SNMP agent to maintain full management. However, using the special Segmenting cable option, it is possible to remove one standard IRB cable and replace it with an SRC cable. This divides the stack

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