Managing With Non-managed Switches

By Ronald Pacchiano | Posted January 13, 2006

I maintain the computer network for a small community center in Florida. The network is composed of three Windows 2000 servers and about 20 Windows XP Professional workstations. Over the next year, we're expecting to add at least another 10 workstations to the network. We also have a couple of access points installed for members with wireless laptops and about a half dozen network printers. As a result, our current switch no longer has the capacity we need to connect all of the devices we're anticipating. So I either need to add an additional switch in order to increase our current port capacity, or I need to replace the current switch with a larger one.

While researching new switches, I noticed that some are called managed switches. I'm not familiar with these and always thought that a switch was for the most part the same as any other switch (expect for maybe brand loyalty). However, these "managed switches" are typically much more expensive then the non-managed ones. They also have a number of features listed in their specifications that I don't understand. Now I'm confused and not sure how to proceed. What is the difference between managed and non-managed switches and would you recommend I get one for our environment? Thanks for your help.

If your background is in small LAN environments (like your community center), I can understand how the discovery of managed switches might be confusing. As you observed, managed switches are usually much more expensive then their non-managed counterparts and, as consumers, the first thing we think of is that if it's more expensive, then it's got to be better. The problem with this logic though is that "better" can sometimes be a subjective term.

Speaking from a strictly technological point of view, managed switches are far superior to non-managed switches, but that superiority comes at a price. More features equal more complexity and often require a skilled network engineer to get the best performance out of them. Due to these factors, you rarely find managed switches outside of medium- to large-sized organizations.

Before we go any further, I can tell you right now that you don't need to invest in a managed switch for your network at the community center. While there are numerous benefits to using them, they are, quite frankly, overkill for the size environment you have. A simple, inexpensive non-managed switch is all you need. Whether to expand your current one or purchase a larger one is a judgment call I'll leave to you. Now with that out of the way, let me see if I can explain the differences between managed and non-managed switches in a bit more detail for you.

A managed switch lets you take control of your network and all the traffic moving through it, while an non-managed switch simply allows Ethernet devices to communicate with one another. For example, when you connect your Ethernet devices (PC, network printer and so on) to an non-managed switch, they usually will communicate with each other automatically. They use a protocol called "auto-negotiation" to agree upon certain communication parameters. One parameter they negotiate is the data rate — generally 10, 100 or 1000MBps. Another is whether to use half-duplex or full-duplex mode.

Full-duplex allows communications to exist in both directions at the same time, while half-duplex allows for only one way communication at any given time. Other parameters include flow-control, for controlling the rate at which data is received so that frames can be processed, and Auto-MDIX, which decides which wire pair to use for transmitting and receiving data. You can monitor this with the simple status LEDs on the switch, which give you feedback regarding link status and activity. Since so much happens behind the scenes, there really isn't much for you to do.

A managed switch, on the other hand, does all of this as well, but also lets you provides you adjust the communication parameters of each port on the switch to any setting you desire. This gives you the option of monitoring and configuring your network in a variety of different ways, as well as giving greater control over how data travels over the network and who has access to it.

Through the use of SNMP (Simple Network Management Protocol), you can view a multitude of network statistics. This includes the number of bytes and/or frames transmitted and received, errors generated and port status. Statistics for each can be viewed for each individual port in the switch. Some managed switches make this data available via a Web server so that you can access this information with a standard Web browser. Others use dedicated or even proprietary software for this. Most managed switches also offer advanced features that help to enhance your control over the network. Here is a chart that showcases some of the more common features available on most managed switches:

Features Benefits
Virtual Local Area Network (VLAN)
  • Isolate traffic between groups of ports
  • Control access to the various VLAN groups
  • Allow devices that need to communicate to each other the maximum bandwidth
  • Bandwidth Rate Limiting
  • Set a maximum bandwidth for each port
  • Prevent unnecessary communication traffic from overwhelming devices
  • Quality of Service (QoS)
  • Allow "high priority" messages quick throughput
  • Define message importance
  • Simple Network Management Protocol (SNMP)
  • Monitor switch port parameters
  • Allows easy access to switch information for HMI, SCADA and other applications
  • Port Mirroring
  • Provides message troubleshooting access
  • Allows messages to be monitored for message content
  • Trunking redundancy
  • Relay contacts, flashing LEDs and SNMP traps help to quickly identify the broken links.
  • Trunking also provides more bandwidth between switches
  • The bottom line is this: If you're connecting a very large network, which is distributed over a large area, then managed switches that provide more diagnostic information about the status of each connection are typically more useful. If, however, you're connecting a network that is limited to a small number of systems on local LAN, a managed switch may add a lot of unnecessary complexity and expense that you don't need.

    I hope this helps clear things up for you, but if you would like to learn more about managed switches and how they work,  visit this site. It has some helpful animated tutorials that might make some of these esoteric concepts a bit easier to understand. Best of luck!

    Adapted from PracticallyNetworked.com, part of the EarthWeb.com Network.

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