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Layer-3 Switching info ????


i want to known about the layer-3 sw and its importnat and Main Feature ...

Cisco Series of Layer-3 Swtiches history ???

And Latest Layer-3 Ios Detail nad its history.

Can you provide me some meterial on layer-3 Switches...... any link or slides

Thanks and Regards


Re: Layer-3 Switching info ????


this might you help you.

Definition of: layer 3 switch

A network device that forwards traffic based on layer 3 information at very high speeds. Traditionally, routers, which inspect layer 3, were considerably slower than layer 2 switches. In order to increase routing speeds, many "cut-through" techniques were used, which perform an "inspect the first packet at layer 3 and send the rest at layer 2" type of processing. Ipsilon's IP Switch and Cabletron's SecureFast switches were pioneers in cut-through switching.

As more routing lookup functions were moved from software into the ASIC chips, layer 3 switches could inspect each packet just like a router at high speed without using proprietary cut-through methods. If a layer 3 switch supports packet-by-packet inspection and supports routing protocols, it is called a "routing switch" or "switch router," which simply means "fast router." For example, Cisco calls its high-end routers Gigabit Switch Routers.

The more deeply a packet is examined, the more forwarding decisions can be made based upon type of traffic, quality of service and so on. To get to this information means digging into the packet's headers to ferret out the data, which takes processing time. To understand how the packets are formed, see TCP/IP abc's. The following shows what is examined at each layer. See layer 3, layer 2 switch, Web switch and virtual LAN.

you can also serch layer3 switch in


Re: Layer-3 Switching info ????

Hi Friend,

Layer 3 switch is a switch which has routing capabilities in it. Traditionaly routing capabilities was built into the routers only and in a LAN environment with lost of Vlans a routers was used to provide the routing among the vlans. As the technology had advanced Layer 3 switches have taken the functionality of both being a layer 2 switch and routing device.

Cisco's first layer 3 switch was Catlyst 3550 which is end of sale now and has been replaced by 3550/3750 which are standalone switch. Cisco's modular layer 3 swicthes are Cat 4500 and 6500.

I am attaching some info on layer 3 switches and configuration guide.

HTH, Please rate if it does.

-amit singh