Switch vs. Router

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To all the Cisco Experts.

What is the difference between a router and a layer 3 switch?


Re: Switch vs. Router


Essentially, in a multi-layer switch, the layer 3 functionality (and other
the upper layer capabilities) are deployed in ASICs to attain wire speed at
those layers.  There are some other minor differences in capabilities, but
generally a layer 3 capable switch is configured very similarly to a router
to take advantage of the layer 3 functionality.

FWIW,
Robert


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Re: Switch vs. Router


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Let's try the simple answer and see if you need more:

A (plain) router doesn't have the ability to make the
rapid and temporary physical/electrical connections
that (any of) the switches make.

A layer three switch, commonly called a switch-router,
is a switch which uses routing protocols and methods
to decide which connections to actually make.

(As opposed to a layer-2 or bridge type router which
typically uses MAC addresses to make such decisions.)

A router (switch or not) is always (network) protocol
specific and uses the logical address and the specific
routing protocols of that network protocol to make
decisions.

If someone points at a device and says, "This router
is NOT protocol specific since it routers some/all of
IP, IPX, AppleTalk etc..." then notice that for EACH
of these network protocols the routing is done separately,
using the logical (e.g., IP) address of that protocol and
the routing protocols and methods specific to that network
protocol.




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