Besides the ports, several other components make up the overall architecture of a switch. The switching engine makes decisions, and the switch memory buffers frames from port to port. The switching fabric connects all the components together. For example, devices such as the Catalyst 29hhXL, 35hhXL, and 40h0 deploy a shared memory fabric where all ports share the same memory pool. The Cat5000 and Cat6000 are store-and-forward switches that use a switching bus architecture arbitration method where a central bus arbiter works with an arbiter on each line card to control queuing for each port. The 6500 with a fabric module installed deploys a crossbar fabric whereby hardware-based ASICs provide many switching paths; this is also known as a nonblocking architecture. Nonblocking in a nutshell means that the switch has more bandwidth than all the ports together. The 6500 can also deploy a local switching fabric so local ports do not ha ve to go through the switching fabric. Modular switches dedicate slot 1 for the Supervisor Engine that: monitors system components as well as the switching functions within the switch. This list contains some common terminology and functionality of the 5000:
• Ethernet ports use a custom ASIC called Synergy Advanced Interface and Network Termination (SAINT).
l Other ports u se a cu stom ASIC balled Syngrgy Advanced Gate-Array Engine (SAGE).
• Encoded Address Recognition Logic (EARL) is an ASIC that works with bus arbitration for packet tra nsfers.
• The Network Management Processor/Master Control Processor (NMP/MCP) aggregates data from processes such as SNMP and RMON and includes information from STP, CDP, and VTP.
• Built-in Gate Array (BIGA) connects the NMP to the 1.2-Gbps bus.
• Line-module Communication Processor (LCP)
• A tyibical Catalyst ioowerrup sel°-test includes such things as an LED check, memory test, and address recognition logic such as ROM, RAM, EARL, and BootROM. Figure 6-t gives you a visual of one of the higher-end modular Catalyst 6000 family devices in case you don't have anything like this in your lab.
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