Francois Labreque wrote:
> Sabrina Kilian a écrit :
>> It is an interesting way to use commodity hardware, instead of custom
>> stuff. Though, the article does make it hard to take them seriously when
>> they use lines like "Modern routers are rarely dumb switches anymore."
> 
> Most comemrcial routers HAVE been switches for the last 20 years.  The
> first packet to come through would be routed by the cpu, but the result
> of that routing table look up would be sent to an interface cache and
> all the packets for the same destination after that would be switched
> directly by the interface hardware, leaving the CPU alone.

Switches have moved up to handling some of the layer 3 protocols and
doing some of the stuff typically thought of as router work. Managing
VLANs and the like, and switching stuff between them. If the router
never had to handle BGP, and the like, then a smart switch could replace
it. Depending on the switch, it might even work where all you need is
QoS and some switching between local disparate IP subnet and VLAN.
However, a smart switch won't replace a router where one is really
needed; handling all the annoying route finding when you have a more
complex topology outside the area of your network. At least, I haven't
seen one that manages BGP. Wiki tells me they may exist.

Still, all of this is smart switches moving up to fill the need of
simpler routers. Any router, barring marketing names, has never just
switched packets on layer 2 like a dumb switch will.

I feel like maybe I am over explaining the joke of "Layer 3 devices are
rarely layer 2 devices anymore."

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