MultiLayerSwitch-ASIC

Question 1

What does ASIC stand for?

Answer 1

Application Specific Integrated Circuit.

Question 2

What is an ASIC?

Answer 2

An ASIC is a piece of hardware with millions of transistors designed to look up information thousands of times faster than a processor.

Question 3

What is the switch fabric?

Answer 3

A switch fabric is likened to the “ethernet” within a switch. It is basically a bus that leads to a forwarding engine.

Question 4

What is a shared bus?

Answer 4

A shared bus is when all port ASICs share the same line to transfer data to the Forwarding Engine. Each port ASIC must wait till given permission to forward data.

Question 5

What is a shared ring?

Answer 5

A shared ring is when all port ASICs are forwarding engines. They wait their turn while one ASIC is in control of the line, and this control is determined by a pulse that must be “captured” on the ring.

Question 6

What are ASICs responsible for in L3 switching?

Answer 6

The same as in layer two–sending info out the correct port, and rewriting the source/destination MAC address.

Question 7

Where is the ASIC Located?

Answer 7

In The Dataplane. Information like MAC addresses, the routing table or access-lists are stored into these ASICs. The tables are stored in content-addressable memory (CAM) and ternary content addressable memory (TCAM).