Using the Cisco SG300-20 Layer 3 switch in a home lab

One of the goals when building up my home lab a few years ago was to emulate a simple production environment that would give me a good platform to learn and experiment with. I’m a big fan of nested labs, and use one on my laptop often. But there are times when you need real hardware to interact with. This has come up even more than I expected, as recent trends with leveraging flash on the host have resulted in me stuffing more equipment back in the hosts for testing and product evaluations.

Networking is the other area that can be helpful to have equipment that at least tries to mimic what you’d see in a production environment. Yet the options for networking in a home lab have typically been limited for a variety of reasons.

• The real equipment is far too expensive, or too loud for most home lab needs.
• Searching on eBay or Craigslist for a retired production unit can be risky. Some might opt for this strategy, but this can result in a power sucking, 1U noise maker that may have some dead ports on it, or worse, bricked upon arrival.
• Consumer switches can be disappointing. Rig up a consumer switch that is lacking in features, and port count, and be left wishing you hadn’t gone this route.

I wanted a fanless, full Layer 3 managed switch with a feature set similar to what you might find on an enterprise grade switch, but not at an enterprise grade price. I chose to go with a Cisco SG300-20. This is a 20 port, 1GbE, Layer 3 switch. With no fans, the unit draws as little as 10 watts.

Features
There is no need to rattle off the complete set of features of the SG300-20, but there are a few that have proven to be especially nice for use in a home lab.

• Full Layer 3 functionality. It is not uncommon to find some lower end switch and read that it is "Layer 3" only to find out it doesn’t support Inter VLAN routing (are you listening DLink?). This switch offers all of the routing scenarios that you probably desire in a home lab. Their 300 series switch is Layer 3, while their 200 series is Layer 2.
• LACP LAGs. Pretty handy to be able to bond links to experiment with in vSphere or hooking up an endpoint like a NAS unit. Maybe you’ve wanted to experiment with switch to switch LAGs. If so, this is a must have.
• Spanning Tree. Why terrify yourself playing around with Spanning Tree in a production environment when you can wreak havoc on your entire network in the comfort of your own home lab?
• ACLs. This sort of falls in the category of Spanning Tree. The only thing more embarrassing than locking yourself out of your home lab switchgear is to lock yourself out of your production switchgear. (not recommended)
• CDP and LLDP.  Have you ever wanted to know what the functional differences were between CDP and LLDP with regards to a vSphere host? This switch can listen for both!
• CLI and SSH access. Nice for change control and documentation.

While it carries the Cisco brand, it does not use their operating system; IOS. But it does offer a CLI that feels similar to other units out there.

Wiring diagram
This is how the unit is currently arranged in my home lab. The second host is not shown for clarity, nor are the dozen or so VLANs used for segmenting traffic.

What it looks like
Courtesy of my $20 rack at Lowe’s and some bracket fabrication, I was able to mount up the unit on the underbelly of the top shelf. This keeps the airflow around the unit good (a requirement), and overall a pretty tidy look in a 2 host environment. Although, I may have to figure out something slightly different if I add another host.

The photo might make the entire setup look big, but in reality, it stands only 30" high.

Room for improvement
Taking an honest look at the unit, there are a few annoyances that bother me.

• Goofy port numbering. On ports 1 through 16, they are numbers left to right, top to bottom. On ports 18 through 20, they go top to bottom, left to right. This is partially due to the mini-GBIC ports on the right hand side. But how about we just stick to one way of ordering them.
• Port count. This isn’t the unit’s fault. It’s just that Ethernet ports get used up pretty fast especially when each vSphere host uses 6 ports (not including IPMI).  20 ports sounds like plenty, but free ports can vanish quickly when counting uplinks, IPMI, storage, and other devices.
• Still a bit pricey.

The SG300-20 will not be the most affordable option for a home lab, but its feature-set pays off, and has been rock solid in my lab environment. In fact, you can find this family of switches in small businesses everywhere. I have no regrets investing a few extra bucks in a decent switch, and will probably be adding another one when the time comes to add a third host or more toys.

– Pete