3-3
Operation
DC/DC Converter
The DC/DC converter converts the 48 VDC on the system power bus to the
necessary operating voltages for its host network services module. The diagnostic
controller monitors and controls the operation of the DC/DC converter.
INB Interface
Each module attaches to both INB A and INB B and has two INB Network
Interface BlockÕs (NIB). The INB NIBs convert canonical frames to Þxed length
data blocks for transmission onto the INBs. For data blocks received from either
INB, the INB NIB reassembles the data blocks received from the INB back into
canonical frames for transmission back through the switching fabric to the front
panel ports.
SecureFast SmartSwitch Architecture
The SecureFast SmartSwitch Architecture of the 9G421-02/9G429-02 module is
conÞgurable for one of two modes of operation: traditional switching (bridging),
or SecureFast switching. The module supports only one of these modes of
operation at any one time.
When operating in traditional switch mode, the 9G421-02/9G429-02 makes
Þltering/forwarding decisions based on Destination Address (DA), with standard
IEEE 802.1D learning. Spanning tree operation for the 9G421-02/9G429-02 is
conÞgurable to adhere to IEEE 802.1D, DEC, or none. The default Spanning Tree
Algorithm is 802.1D.
When operating in SecureFast switching mode, all Þltering/forwarding decisions
are made on a DA-SA pair and its receive port. SecureFast switching mode
provides value-added network services including Topology, Connectivity, IP
Multicast, Control, Security, Application, Address Management, Dynamic
Mapping, and Directory services. For example, Topology Services included
conÞgurable options ranging from simple spanning tree implementations to
fully-meshed active topologies. Other services and features supported in
SecureFast switching mode are described in detail in the Cabletron White Paper,
IP Host Communication in Bridged, Routed and SecureFast Networks.
