Starting from Scratch

Some days, you probably get a bit fed up with your network and just feel like scrapping it and starting over. Well, what if you could? What would your brand-new campus network look like? Some companies actually get that opportunity, be they start-ups building new infrastructures or established companies wiring new buildings. Often these networks follow a distinct pattern. With no legacy equipment to consider, executives opt for both hot technologies such as Layer 3 switching and evergreens such as IP and Ethernet. Today's recipe for a new network installation looks something like this:

1: Preheat the desktops

Companies usually start off with Enhanced Category-5, or Cat-5E, wiring to the desktop. In past years, Category-5 has been the standard, serving well in carrying traffic up to 100M bit/sec. But users are looking to the future.

"We're wiring for growth," says Dave Orifice, supervisor of network operations at Banyan Worldwide Services, a consulting division of Banyan Worldwide in Westborough, Massachusetts.

Although Gigabit Ethernet is supposed to run over ordinary Cat-5, Cat-5E ensures that Gigabit Ethernet over copper will work. Orifice says the company has no definite plans to run Gigabit Ethernet to the desktop, "but if the technology goes that far without getting too expensive, we're ready."

Few would dispute the assertion that any new network interface cards for the desktops should be 10/100M-bit/sec Ethernet NICs. At one extreme, gigabit rates to the desktop would be extravagant. At the other, 10/100M-bit/sec NICs are as inexpensive as 10M-bit/sec-only NICs ever were. As for LAN technologies other than Ethernet, they are rarely even considered for new networks these days.

2: Combine in a large closet

Desktops usually plug in to a 10/100M-bit/sec Ethernet desktop switch in the wiring closet. Here, port density is a big consideration.

This was foremost on John Reppucci's mind when he installed a new network for his company, Arbella Insurance. He used Extreme Networks' Sum-mit48 desktop switches, each of which has 48 ports of 10/100M-bit/sec Ethernet in a fixed configuration.

All the 1,400 desktops are now capable of getting 100M-bit/sec of switched bandwidth, a drastic upgrade from the decade-old 10M-bit/sec shared hubs the company replaced.

But in the wiring closet, it's possible to have too much bandwidth. "We made access for end users so quick, we started overrunning the servers," says Reppucci, Arbella's datacom supervisor. "Now, we're looking at Gigabit Ethernet to the servers."

Many times, companies will choose low-cost stackable switches for the closet, but not always. Suffolk University recently put in a new building for its law school and used 3Com's chassis-based Core-Builder 9000. The switch is a high-end model often used in network backbones.

"It sounds crazy, but with the density requirements of our users, we couldn't do it with stackables," says Fuad Yatim, director of network services at the school. The CoreBuilder 9000 can hold more than 500 Fast Ethernet ports.

2a: Add a little wireless to taste

The bandwidth and stability of wireless LAN technology are getting to the point where many more businesses are considering it, mainly for the freedom it gives employees to move around a building or campus with their laptops.

Start-up is quickly building out its net and evaluating 11M-bit/sec wireless products for its sales force, says Brandon Mikkelsen, a network manager there. "They are a migratory type of employee," he says of salespeople.

If different offices have the same type of access points, salespeople can go to those offices and be automatically connected to the network, Mikkelsen says.

3: Mix with the backbone, and connections to a WANFrom the wiring closet, new networks often run Gigabit Ethernet over fiber-optic lines to connect to a mesh of Layer 3 switches interconnected by even more Gigabit Ethernet. Traditional routers can't handle the speeds or hit the low price points of Layer 3 switches. Further obviating the need for traditional routers is the fact that builders of new networks limit their protocols to IP.

In a small network, Layer 3 may not be necessary. Mikkelsen says he's planning to keep his network of 1,500 nodes flat (that is, free of subnet boundaries) and switched. He adds that he has the option to put Layer 3 capabilities into his Foundry Networks switches at a later time, if the flat network gets unwieldy.

Many users aren't hesitant to put Layer 3 switches from a smaller vendor, such as Extreme or Foundry, into a new network. Although router king Cisco can provide all the elements of a campus network, including Layer 3 switches, a spokesman couldn't name any enterprise customers that had installed new networks with Cisco equipment.

However, Cisco routers would fit into a network for wide-area connections, says Dave Passmore, research director at consulting firm NetReference. Layer 3 switches usually don't have WAN connections, so a traditional router would connect to the campus backbone and be used to transmit data over frame relay or ATM, he says. uses a Cisco router to moderate connections between the WAN and its Cabletron Layer 3 switches in the backbone, says Jim Hutchinson, manager of network operations there. Over the WAN are the company's Web site and back-end fulfillment operations.

3a: Leave the door open for voice

There's a lot of hype about voice-data convergence, and while many users don't run voice on their data networks today, they are leaving room for it in the future. They are making sure their campus switches support the IEEE 802.1p prioritization bits that would be required for it to work.

Companies already used to traditional phone systems aren't rushing to put Ethernet phones on their desks. "Most people are assuming their PBX is going to be around for a few years," Passmore says.

On the other hand, some companies -- including new companies that have never owned traditional PBXs -- are looking to take the plunge into convergence very soon. "Voice over IP is definitely going to be implemented this year," says's Hutchinson. The company is even looking at videoconferencing as a possibility between the headquarters and the fulfillment center, which are 30 miles apart.

4: Garnish with the servers, and serve

The servers can be connected to the network in several different ways.

Hutchinson connects some servers directly to his Layer 3 switches in the backbone, while some connect through an intermediate Fast Ethernet switch that has a gigabit uplink to a Layer 3 switch.

Load-balancing server switches are another option, but they are catching on more in Web server farms. "So far, we've only put the [server] switches on servers facing the Internet," says Marc Felton, a network engineer at NBC Internet, formerly Such switches are used to handle large volumes of traffic and protect against failures. "None of our internal stuff requires we have absolutely zero downtime."

Whatever type of switch is used, network managers say they prefer to connect servers at the next speed up from the desktops.

While all this may not add up to the dream network for all, it's the one people are implementing today to take them through the early 2000s. "We feel it's a good foundation for at least the next five years," Reppucci says.

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