Design considerations for small network

[brian03801]

Hello all,

I am currently in the process of refreshing the network infrastructure for the company I work for, and, as part of that process, I am taking this as an opportunity to look at a redesign. We have a very small amount of Cisco hardware at the moment (the bulk of it is from another vendor which shall remain nameless), but being that I have a CCNA I want to go full Cisco this time around. 

Before I get to my questions, I want to explain our current setup:

The company consists of a single 60,000 sq/ft facility with approx. 200 endpoints, of which 70 are IP phones. The network consists of two Layer 3 stacks trunked over 10Gb fiber, with the front-of-house main stack consisting of six switches, and the back-of-house stack consisting of two switches. Voice and data networks are separately wired and logically separated in the stacks using VLAN's. In the Cisco world I guess the main stack would be Core/Dist./Access and the intermediate stack would be Dist/Access. We are a vSphere environment (90% virtual) and our virtual infrastructure is "plugged in" to our main stack (this accounts for approx. 45 endpoints). Over time we have further segmented the network using additional VLAN's (Wifi, various sub-systems, etc.) and the setup has worked quite well for us, though I'm sure by some standards it might not be very pretty. We see at-or-near wire speed (gigabit) for network services and between endpoints. 

So, where I start to get lost is when I start looking at "by-the-book" topologies, specifically the three tier approach and the collapsed core model. For us, it seems wasteful to separate distribution and access layers, as the nature of the business does not lend itself to well defined borders between departments and/or job functions, and we don’t have any geographical considerations to take into account. What makes more sense to me, is to peel out the core and leave my distribution and access layers combined (if we change anything at all). What I’m really wonder at this point is, well, if it ain’t broke do I need to fix it? What are the potential problems with just keeping things as they are? Are there other options I should be considering that I'm not aware of?

I appreciate any insights.

[Leo Laohoo]

Since the introduction of Cisco Instant Access, the three layers have turned to logical design.  With Instant Access, the parent switch can become core/distro and the Instant Access switch becomes the access, however, if the configuration and control of the Instant Access switch is conducted by the parent switch, this means that the Core/Distro/Access becomes one big logical unit.  

[Marvin Rhoads]

if it ain’t broke do I need to fix it?

.. no you don't need to. :)

The classic 3-tier architectures are more and more a relic vs. a best practice. Given the small size of your network, keeping it relatively flat and simple is definitely the way to go.

I'd decide, based in large part on additional consideration of your virtual server environment, whether it makes sense to put a beefier core in with more 10 Gbps ports. If you have only a handful of ESX hosts, it may make sense to think about collapsing them onto 2-3 physical servers with 2 x 10 Gbps uplinks from each.

Your overall port count, speeds and feeds matter more in your environment than leading edge features for the most part. Any good reseller should be happy to send over a presales engineer to work up some alternatives for you so that you can compare price, performance, future needs etc. tailored to your needs.

[brian03801]

I appreciate the feedback. With all of the options out there it's difficult to know which to go sometimes. 

[Leo Laohoo]

With all of the options out there it's difficult to know which to go sometimes. 

This is why we always recommend to organize a systems integrator otherwise it'll cost more if done wrong.

[Marvin Rhoads]

Somebody like me. :D