3Com takes

3Com Corp. this week at the CeBIT show announced a Gigabit Ethernet switch and Layer 3 switching software that could help IT professionals build – and pay for – a LAN backbone piece by piece instead of using one or two big pieces of iron in the core.

The Switch 4060 and Extendable Resilient Networking (XRN) software could be used to build a Layer 3 network backbone incrementally by linking fixed-configuration boxes together into a single, logical, core routing switch. The company says this “Lego” approach to building a backbone could be a cost-saver for users that may have considered buying a large backbone switch chassis but are concerned that the chassis could become obsolete before the network grows into it.

XRN software can link together two to eight 3Com Layer 3 stackables, which can be managed with a single IP address. The first version of XRN will link two stackables for a total of 48 Gigabit Ethernet ports. Later versions will support four and eight switches in an XRN group, providing up to 96 and 192 Gigabit ports, respectively.

A connector module is required on each switch to stack the boxes together with XRN, but once connected, the link allows the stack to move packets in and out of ports of different switches similar to modules in a chassis-based device. Switches do not necessarily have to be in a “stack” either, as XRN could link boxes as far as 10 kilometres, the longest reach for Gigabit Ethernet over single-mode fibre. Configuration settings – such as network policies – and routing tables are shared among the boxes, and failover of traffic and settings is supported.

Up to eight Gigabit Ethernet ports can be trunked together between switches to provide a multi-gigabit “backplane” between the boxes. 3Com says a 10 Gigabit Ethernet interconnect is being planned for XRN support, but that is about a year away from availability.

Managing multiple fixed-configured switches from as a single device appeals to Jim Maass, director of technology for the Tahoe Unified School District in northern California. Maass plans on using fixed-configured 3Com Gigabit Ethernet switches to link several of the district’s schools over fibre-optic lines donated by the local utility company.

“We’re going to have to make it easy to manage multiple devices across long distances, and were looking at the XRN technology to help do that,” Maass says. “If this were a business, I’d have four or six people working for me, but being in education, I don’t. If I have spend a little more up front to help us be more efficient, that’s OK.”

The ability to stack fixed-configured boxes into a single logical device is nothing new, but this technique has been limited to the Layer 2 area mostly for wiring closet deployments. Competitors to 3Com, such as Cisco Systems Inc. and Allied Telesyn International Corp., offer stacking products and software for linking Layer 2 switches together as one device, but 3Com’s venture into Layer 3 stacking is a first, observers say.

Stacking Layer 3 “pizza-box” switches to build a backbone could have several advantages, says Martha Young, research director at Enterprise Management Associates Inc.

“The build-as-you-grow philosophy [keeps users from] buying more than they need in any point in time,” Young says. Another benefit to building a piecemeal backbone with XRN is the ability to have the backbone switches spread out, but centrally managed.

Price and switching capacity are factors to weigh when considering using fixed-configured switches instead of a chassis in a LAN core. Stackable switches are cheaper per port – fixed Gigabit ports cost less than modular Gigabit ports. But cobbling together fixed-configured boxes can limit the overall capacity of a backbone to a few gigabits, even with trunking, whereas the backplane or switching fabric on some switch chassis can provide 100Gbps to 400Gbps of bandwidth between ports on different modules.

The Switch 4060 is a stackable, Layer 3 switch with 24 Gigabit Ethernet ports that could be used by small businesses as a backbone switch. The box allows users to choose their Gigabit medium, with a mix of copper, fibre and gigabit interface converter (GBIC) ports that all support up to 1000Mbps Ethernet.

XRN software will work with the new Switch 4060 and with 3Com’s SuperStack 3 Switch 4900 series switches.

3Com also announced Layer 3 software upgrades for its two chassis-based switches, the Switch 4005 and 4007. The upgrades will add hardware-based routing capabilities to the two switches. They will also add Virtual Router Redundancy Protocol (VRRP) to the 4007, which will allow a 4007 to be configured together with a second standby 4007.

The Switch 4060 will be available in June for US$18,000. Users will have to wait until the second half of this year for XRN upgrades for 3Com SuperStack 3 4900s or the 4060. 3Com would not give the pricing for an XRN stacking software upgrade, but intimated that it would be more significant than the cost of stacking Layer 2 switches together, which runs around US$200 per device. The Layer 3 Switch 4005 and 4007 are available now for US$10,000 and US$34,000, respectively.