Hi, I'm a college student & my final year project is to upgrade & reconfigure my college network... The college has 700 PC's. It's an adhoc network. I have recommended VLANS. In all there will be 7 VLANS. I want to know which model of Layer 3 switches I should recommend to the college. It shouldn't be very costly. Please give me your suggestions/ recommendations.
Purist wording nit-pick follows :)
Packets at layer 3 are not switched. They are routed.
Switching is what is done with packets at layer 2.
Marketroids and salescritters will often tag a device as a "Layer N Switch" because they believe it will sound better - in olden days it was presumed that "switching" was faster than "routing" so even though what happens at layer 3 is routing they call it switching.
Naming can get really "fun" when multiple functions are combined within a single box :)
Now, having been nitpicky, I'll point to
rick jones
i suggest you start with stating the problem you want to solve not how you want to solve it.
once you have that the rest of the limits you have to work to get clearer.
So - QoS needed? Power over Ethernet? a few big switches or lots of small ones?
Or - start with some sort of reference design to show you how it is done, and then try to translate that into something you can build.
Cisco have some good design docs that explain general principles as well as how they suggest you apply their products - have a look at:
The design may get cheaper if you only use layer 3 in some locations - maybe just for 1 or 2 core switches.
The rest of the devices could be layer 2 only, which are often cheaper (or the same device, but without an extra L3 software licence).
Again - look at design and decide which features you need, then go shopping.
>
I am not so sure how the words are supposed to be defined, but I might say that if it was done at the hardware level, including hardware (or FPGA) implementations of state machines, then I wouldn't mind it being called switching.
Software has to update the tables needed by the hardware. Hardware changes the source and destination MAC address, increments the TTL, and modifies the checksum as appropriate.
That is different enough from software routers that it deserves a different name. I have no idea how layer 3 switches are actually implemented.
-- glen
Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.