Quick Question on Core Network

Just a quick question on Core Layer of the Network...

I am moving routing away from our heavily used core to the Dist layers, which will keep VLANS confined to their requirements.  However Cisco recommends the Core do only Layer 2 and minimal Layer 3, I really cant see how the core can do only layer 2... how would this work?  Also, with Voice, Mgmt etc, each zone of the network would need a different voice and mgmt subnet as you wouldnt want vlans trunked all over the network, as the Cisco Network Model is meant to stop that.

Any advice would be appreciated.
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bkepfordConnect With a Mentor Commented:
Your Core is the switch between your distribution layer traffic. You don't pass VLAN information because all VLANs terminate at their layer 3 gateway (the distribution layer)
Cisco is just saying it is a bad idea to make your core layer 3 switch be a default gateway for all your other devices and to get all the vlan traffic.No matter how big a switch it is just a silly idea.
bromley_collegeAuthor Commented:
That makes it all clear now, thanks for that, I think the way they write it down is can sometimes leave you wondering a bit more than you should.
Yeah, Cisco is good at that.  Don't get me wrong, they have great products and a wealth of available information; but they've always excelled at taking a somewhat complex topic and making it seem far more complicated.
Maybe this is a contributing factor to the value of Cisco certs.

Did you have any questions regarding my explanation? Let me know.
bromley_collegeAuthor Commented:
Hi bkepford

Your explanation is fine, thanks for that.  Since routing will happen at the DIST layer the core will not need to route traffic as the native vlan will pass down to the remote DIST layer should that be the destination.  Obviously some vlans may be trunked across but for now we are getting to the testing phases only, so time will tell.

Thanks again
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