Buyer's Guide to Enterprise Switches

By Drew Robb | Mar 2, 2011 | Print this Page
http://www.enterprisenetworkingplanet.com/netsysm/article.php/10954_3926806_2/Buyers-Guide-to-Enterprise-Switches.htm

In simple terms, switches are used to interconnect the various parts of a network. As a core component of any Ethernet-based local areas network (LAN), they are available at various bandwidths -- typically 100, 1000 or 10,000 megabits per second (Mbps).

According to analyst firm Dell'Oro Group, 1000 Mbps enterprise switches have been dominant for quite some time, accounting for about two thirds of the market. Their market share, though, has slipped by two percent over the past two years.

More significantly, Dell'Oro numbers show the growth of 10,000 Mbps gear at the expense of 100 Mbps units. While the former has growth from 18 percent in 2009 to almost 27 percent today, the latter has slumped from 16 percent to less than 10 percent. Clearly, 100 Mbps is going away, at least in the enterprise sector. 1000 Mbps continues to take on most of the load, but 10,000 Mbps (also known as 10 Gbps, 10 Gb Ethernet or 10 GbE) is where the field is heading in the long term.

"10 GbE, which is very high speed, has become more prevalent over the last two years as prices have come down," said Sven Rasmussen, networking solution architect at CDW.

He said that data center virtualization has been a leading driver of 10 GbE. When users consolidate and virtualize, they may shrink their infrastructure, but the volume data on the network does not shrink. Thus 10 GbE becomes a necessity in a highly virtualized environment. Bigger pipes are required between servers as all of the information previously spread across a large number of servers is now going through far fewer boxes.

The advent of higher performance switches, of course, bodes well for sales. From $15.2 billion in 2009, Dell'Oro estimates 2011 will end with $19.5 billion in enterprise switch sales. Cisco is the giant in this segment. It has carved itself a massive slice of that pie -- three quarters -- with HP and Juniper taking up second and third place respectively.

Switches in enterprise networks

The average enterprise network generally has a core switch, with additional distribution layer switches that operating below it to bring all the information into the data center and disseminate it out to the access layer where the end users are located and there is less data traffic. This is the most traditional model of core, distribution, and access layers (three layers). Depending upon the size of the organization, though, some can get by using an enterprise switch to serve at multiple layers. For example, if you have a small network and want to have an enterprise switch, you can have a "collapsed core" – which involves having multiple layers within the same switch.

"Another key function to explain is that some devices are layer two -- synonymous with switching -- which allows for extreme high-speed," said Rasmussen. "Sometimes, users prefer these switches to incorporate layer three -- synonymous with routing -- which allows the network to be better organized by segmenting the infrastructure into discrete pieces. With good management tools on top of that, it can be more efficient to manage than just one big, busy network with tons of data flying around."

But while there are many switches around, what enables Cisco and its closest rivals to dominate the market is that they offer sufficient back-end infrastructure and support for enterprise users. Cisco, for example, has SMARTnet.

"It is important when choosing a networking provider that you not only look at the hardware specifications, but also at the kind of organization they have to support their equipment," said Rasmussen.

Important enterprise switch features

The best switches on the market, of course, are 10 GbE. These typically contain the latest and greatest. Most, for example, are fully managed, meaning they have some type of interface that allows you to see the entire network. Most of the big vendors supply one piece of software that lets you see your whole network and all of its information.

Other common features and specifications to consider include:

  • Port Count: It is wise to have an idea of how many ports you might need. Switches can be purchased with a handful of ports up to 50 or more. But as you pay for those extra ports, don't buy what you won't use.
  • Port Type: ports are typically 10 GBE, 1 Gb, and fiber or copper.
  • Management: Some switches are managed while others are unmanaged.
  • Switching Capabilities: Some switches operate at layer 2 -- the data link layer -- working with MAC addresses associated with network interface cards. Others operate at layer 3 -- the network layer -- providing high performance for network routing.
  • Uplink Speed/Media: choices are generally 10/100/1000 copper, 100 MB fiber, 10/100/1000 fiber and 10 Gbe copper.
  • Additional Features: These can include PoE (see below), PoE+, fanless systems and IPv6 host/management, as well as redundancy features for high availability.

Power over Ethernet (PoE) Features

With PoE, you only have to run a single cable to support both IP phones and desktop equipment. If you are rebuilding your network or creating an entirely new network, PoE is a smart idea as you avoid paying double for cables and cable pulling. In a large organization, PoE eliminates the heavy costs associated with the sprawl of cables.

"When you consider how much PoE has come down in cost recently, it is a great feature to consider," said Rasmussen. "Some vendors even include PoE as a standard feature today. In most cases, the charge is negligible when you compare it to the cost of not having it."

With POE, keep in mind that there is a difference in switches that are known as standard PoE vs. PoE Plus. The difference is whether the switch is capable of delivering 15 watts of power, or more. Some phones require only 6 W of power, while others require 12 -- enough for standard PoE. Certain equipment for physical security, however, can require more than 15 W of power -- a case where you have a need to use PoE Plus, which provides up to 25.5 W of power.

"There is no comprehensive approach to the way that PoE works with different equipment," said Rasmussen. "You need to know what your power budget is, and select from there."

Cooling/power cost is another factor to consider in the purchasing decision. Vendors often seek to differentiate their products by highlighting their "green" features. Switches that use far less power than older models and require less cooling are increasingly coming on the market.

"If products and vendors are equal on all other levels, buyers should consider the product that provides the greatest potential for additional savings due to reduced energy use," said Rasmussen.

Over the next few weeks, the remaining articles in our buyer's guide will cover the top three vendors in the enterprise switch marketplace.