[c-nsp] Campus Network Design advice

[Marc Archer]

Hi Guys,

I'm looking for some advice on redesigning our campus network.

We have around 2500 devices on our site which are spread across multiple
buildings. At present the network runs on a (legacy) single flat VLAN which
has caused us more than our fair share of headaches of late. Basically we
are looking at 2 design options :

The first option we have considered is to have a "router on a stick" at our
core and trunk VLANS out to distribution switches in each building (and on
to workgroup switches etc), leaving all routing to be done at the core. This
would allow us to have all VLANS available in each building but I'm not sure
if this is still going to be a problematic design (with VLANS extended all
over the site).

The other option we have been looking at (see attached) is to have L3
switches as all our distribution switches and contain VLANS to a particular
building. This seems to be a neater solution to me, but I'm not sure of the
best way to connect the distribution switches back to the core. I would also
like to connect adjacent distribution switches together for redundancy, so
I'm wondering if I should be looking at a heap of /30 links between
distribution switches & the core (and run OSPF) - or just use a L2 network
and let STP manage the links.

I havent had much playtime on networks this size so any advice would be
greatly appreciated.

M.