Switching & Routing

Difference b/w Switching & Routing.
In short, If packet forwarding is dependent on mac then your doing switching and if it IP then your doing routing.

Difference between L3 switch and a Router.
Router does forwarding through S/W algoritms whereas L3 does through inbuilt ASICs.
In latest trend, any forwarding done in h/w is named as a switch :-).

L2 switch is a bridge which forward the packets based on MAC address.

Switch is faster than a router because forwarding is built in h/w.

bridges can’t block a broadcast (where a data packet is sent to all nodes on a network). Broadcasts can consume a great deal of bandwidth. Routers are able to block broadcasts, so they provide security and assist in bandwidth control.

Switching:
Ethernet is fundamentally what we call a shared technology.And that is, all users of a given LAN segment are fighting for the same amount of bandwidth.

A by-product that we have in any Ethernet network is something called collisions. And this is a result of the fundamental characteristic of how any Ethernet network works.Basically, what happens in an Ethernet network is that many stations are sharing the same segment. So what can happen is any one of these stations can transmit at any given time.And if 2 or more stations try to transmit at the same time, it's going to result in what we call a collision.

It's also important to understand fundamentally how transmissions can occur in the network. There's basically three different ways that we can communicate in the network.
1. Unicast
2. Broadcast
3. Multicast

in shared bandwidth, Broadcasts Consume Bandwidth & Processor Performance.







References:
http://www.e-tutes.com/index.html
http://www.e-tutes.com/lesson8/networking_fundamentals_lesson8_1.htm
http://www.tcpipguide.com/