Cabletron Systems SmartSwitch 9500, Hardware And Installation Manual

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Operation
3-2
ATM Cell Traffic Flow in the 9A600
The 9A600 SmartSwitch utilizes several innovative features that result in a
completely redundant, fault-tolerant design. The most important hardware facets
of the 9A600 features are the Cabletron Systems ASICs, and the i960 HD RISC
Processor.
Cabletron Systems ASICs
The 9A600 SmartSwitch utilizes four separate Cabletron Systems designed ASICs
to perform switching functions. Refer to Figure 3-1 to see how these four ASICs
work together to provide proper trafÞc ßow. The deÞnitions for these ASICs are as
follows:
Queue ASIC
The 9A600 has four Queue ASICs installed on the motherboard. These ASICs
support 16 priority queues each. The Queue ASICs support all classes of ATM
service including Constant Bit Rate (CBR), Variable Bit Rate (VBR), Available Bit
Rate (ABR) and UnspeciÞed Bit Rate (UBR). The Queue ASICs also manage all cell
transfers to the Utopia ASICs, using a weighted round-robin algorithm.
TDM (Time Division Multiplexer) ASIC
The TDM ASIC is the central switching engine of the 9A600. The TDM ASIC
maintains the connection table, gathers statistics, and provides Usage Parameter
Control (UPC) policing. The TDM ASIC supports up to 128k virtual connections.
SARI (Segmentation and Reassembly Interface) ASIC
The SARI ASIC is the interface that controls the data ßow between the TDM Bus
and the i960 Host Processor. The SARI ASIC has a 768-cell queue and provides the
trafÞc management features of the 9A600.
Utopia (Universal Test and Operation Physical Interface) ASICs
The 9A600 has four Utopia ASICs whose role is to process ATM cells from the
ANIMs to the TDM Bus, and vice versa. In addition, the Utopia ASICs are
responsible for performing path lookups and outbound header translation.
i960HD Processor
The i960HD processor, working with the four types of ASICs deÞned earlier, is
responsible for distributed management functions, signalling, SNMP
management and serving as the in-band management LAN Emulation Client
(LEC) for the module. The i960 also supports out-of-band management interfaces.