Almost a Flat Network Design

[WiLL-I-Am]

Hi,

We have this recommended way of 3-Tier Switching Network Architecture, so I want to know how can you fit it here, and how 3-tier switching network could be beneficial here.

Imagine there is a University with two campuses, and 500 hosts on each campus, we can easily have one flat network of 2x6509 VSS(together) on each campus(with bunch of VLANs and Private Vlans), and connect the two campuses with a 4 channel 10GB fiber routed link to a router. so this is a 1 Tier Switching Architecture, what is the downside to this.

Thx

[Leo Laohoo]

500 host all terminated to a pair of 6509 VSS?
What downside? Tell us more about this network?

[WiLL-I-Am]

Yes, the whole campus network is terminated to a pair of 6509 who is connected to another pair of 6509 via a router.

the only downside I can think of is when the cat6a has to travel longer than 100, especially in buildings that are so wide horizontally, should we use Ethernet extender for this? how do they usually address cable reachablity in these type of buildings?

or buildings with so many floors, how the cable reach the mdf?

[Leo Laohoo · Accepted solution]

Get fibre to do inter-connect between each building and chassis.
Depending on the size and shape of building, put switches in every floor.

[Giuseppe Larosa · Accepted solution]

Hello Will-I-Am,

do you understand that is better to deploy per floor access switches with fiber based uplinks to the C6500 instead of using many LAN extenders over fiber ?

Because the number of required fibers will be less and an access layer switch cost is not so high.

Also LAN extenders introduce a non managed possible point of failure.

This is even the most important aspect the manageability of the resulting network.

Edit:

historically Flat networks are networks not using Vlans and having a single broadbast domain with all users on it.

The Cisco terms for a design that have devices acting as core/distribution at the same time can be collapsed core.

Hope to help

Giuseppe