L3 Switching

[Deepak Sukumar]

I was reading on L3 switching . 

If I ping from 10.1.1.1 to 20.1.1.1 what happens if it is an L3 switch .I read it does ASIC switching .what are the advantages of using ASIC switching.

I am of the opinion if I have an L3 switch as per the topology below ,Inter vlan communication can happen using L3 switch ,without an usage of a router .

What is the difference that an L3 switch provide from an router. Please explain the traffic flow in a L3 Switch

Clipping from Book

The L3 switch possesses specialized hardware chips called application-specific integrated circuits (ASICs) that are preprogrammed and designed to route between Ethernet ports at high speed.

Traffic between devices within the same VLAN, such as ComputerA and ComputerB, is switched at Layer-2 as normal. The first packet between devices in different VLANs, such as ComputerA and ComputerD, is routed. The switch will then cache that IP traffic flow, and subsequent packets in that flow will be switched in hardware

The topology is as follows

Router

|

|

Host A in VLan 1000-------------------L3 switch----------------------VLan 1000 Host B

10.1.1.1                                                |                             10.1.1.2

|

Vlan 2000--Host D

20.1.1.1

[Joseph W. Doherty]

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Posting

Do you have a question or are you just making a comment?

BTW, the "book" is describing flow based L3 switching or MLS (multi layer switching).  Newer Cisco L3 switches use CEF switching.

[Deepak Sukumar]

I am still unclear on L3 Switching ...How does it work

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Logically it works like a router.  Packets enter the L3 switch and it routes them.

Physically, it depends on the platform.  Usually, as you noted in your OP, ASICs are used. They are "special" hardware placed in a L3 switch.  The application, in "application-specific" in this case being routing.

This is similar in concept to "special" hardware to accelerate some mathematical functions, graphic functions, cryptographic functions, etc.