Jury is out on early gigabit

As products start to ship, interoperability and management remain unsettled

By Stephen Lawton

Gigabit Ethernet has finally arrived, but it's come with an assortment of migration issues.

During the last three months, culminating with NetWorld+Interop, a slew of vendors have begun shipping or have given near-term ship dates for their gigabit Ethernet products, including Alteon Networks Inc., Extreme Networks Inc., Foundry Networks Inc., and others. But while this is signaling managers that gigabit Ethernet's time has come, buying into this high-speed technology too early may cause more headaches than it's worth.

Proprietary hardware, interoperability questions, and management shortcomings are issues potentially accompanying any purchase of a gigabit Ethernet product today.

Moreover, this scenario isn't likely to change until mid-1998 when the gigabit specification is complete and standards-based hardware becomes available.

Despite the fact that so many products are shipping, the interoperability scenario has not improved since last spring's NetWorld+Interop in Las Vegas when attendees saw a demonstration of several gigabit Ethernet products on a single network. However, those devices were not operating in a fully automatic mode, said Bobby Johnson, president of Foundry Networks Inc. in Sunnyvale, Calif.

In order to interoperate, the devices had to be hand-configured and some even had specific features turned off in order to connect to other vendors' products. For example, the Alteon NIC had its proprietary Jumbo Frames feature turned off when connected to Foundry's FastIron Switch because Foundry does not support that feature, said Johnson.

And because the gigabit Ethernet products that are shipping today are considered prestandard, such will likely be the case again at the NetWorld+Interop demonstration in Atlanta.

Hoping to solve the interoperability issue, the Gigabit Ethernet Alliance, a trade organization comprised of gigabit hardware vendors, is developing a nonpartisan suite of interoperability tests that it plans to conduct this month at the University of New Hampshire.

Jumping the standards gun

At the root of the interoperability problem lies the lack of a final gigabit Ethernet standard and a slew of prestandard products that have been developed in its absence. Although companies such as Alteon, Extreme, and Foundry have shipped products since July--and GigaLabs shipped as early as March--the IEEE standards body is not expected to finalize the standard until March 1998. The IEEE 802.3z Task Force approved some basic components of the proposed specification earlier this month, but the committee is still in the editing and public comment stages.

However, small pockets of vendors are at work sorting out how to make their proprietary hardware work with other vendors' products. For example, Alteon and Extreme recently said that they conducted their own interoperability tests, and they claimed to have successfully executed auto-negotiation of connections and the capability to negotiate and exchange flow control data.

This was accomplished even though Alteon incorporated its Jumbo Frames technology into its offering, a feature not found in the draft specification or supported by other vendors.

Similar tests were conducted recently by XaQti Corp. with GigaLabs, and even as far back as springtime Prominet Corp. with Packet Engines Inc. claimed to have exchanged packets.

Impact on users

One possible consequence of implementing a proprietary technology is becoming locked into a single vendor's hardware, said George Hall, president of SNA Internetworking Technologies, in Sacramento, Calif., an early adopter of gigabit Ethernet hardware. However, Hall said that interoperability was not a consideration when he purchased an Alteon AceSwitch and the Alteon NIC, because being tied to a single vendor was acceptable if the product solved a significant problem. In his case, it meant installing the switch as a preemptive strike against system overloads of his World Wide Web and Network File System (NFS) servers.

Hall claims to have installed the switch into his main production environment and successfully connected to his company's Sun Microsystems Inc. Ultra 1 and Ultra 2 SPARC servers.

"It's not just gross throughput," he said, emphasizing that the addition of gigabit Ethernet has improved server performance. Hall estimates his servers' efficiency increased 20 percent because the switch "just clocks faster."

Another early adopter of gigabit Ethernet is Mitchell International, a San Diego publisher of automotive books and CD-ROMs that bought the XLNT Millennium 4000 because of concerns that its FDDI network might become overloaded. Mitchell International uses a lot of database- and graphics-intensive applications, and according to network systems analyst David Smith, the company anticipated further growth and a saturated network. Smith said he was less concerned with buying a proprietary switch because XLNT was the only model on the market that supported his existing FDDI backbone.

Smith doesn't view gigabit Ethernet as a replacement for his existing network, but rather as an extension to his existing infra-structure.

"Gigabit is the next layer glued on top" of his existing FDDI network, Smith said. Migration must be seamless and he "always [must] be able to get to anything from anything" on his network, he added.

Adding to the interoperability scenario, the onslaught of gigabit Ethernet products will generate a packet flow that exceeds the capabilities of today's monitoring and testing equipment. However, a gigabit RMON (remote monitoring) specification is expected to be completed in the same timeframe as the forthcoming gigabit Ethernet standard.

Also front and center among concerns are management shortcomings depending on which vendors' products are purchased. Managers are left to decide in advance what level of service guarantees they will need to provide for their networks.

For instance, Cupertino, Calif.-based Extreme Networks has loaded its switch with ATM-class, service-level guarantees according to the philosophy that users need server-oriented, policy-based management. To meet these stringent requirements, the servers monitor the network's health, and Quality of Service (QoS) is employed to maintain a specified performance level.

At the other end of the spectrum are those vendors, such as Foundry Networks, that take a minimalist approach by including basic management capabilities and prioritization. "If you throw enough bandwidth at a problem, it will disappear," said Foundry's Johnson.

Buying proprietary software is an established practice, said Mary Petrosky, senior analyst with the Burton Group, a consultancy in Midvale, Utah. She pointed to Cisco Systems Inc. as a major supplier. "Users are still buying IGRP [Interior Gateway Routing Protocol from Cisco], even though OSPF [open shortest path first] is the standard," she said.

But Petrosky cautioned that proprietary hardware is different. "Don't buy [gigabit hardware] today unless you get the vendor to agree to upgrade you to a standards-based [model]," she said, adding that the vendor should "do the upgrade for free."



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