Future I/O Spec Merges WANs, SANs
From the May 31 issue of Internet Week:
techweb.com
May 31, 1999
Future I/O Spec Merges WANs, SANs by Mitch Wagner
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Want to put your server in Milwaukee and your storage in Seattle? Major
vendors including Compaq, Hewlett-Packard and IBM last week unveiled a
plan to help that happen.
The Future I/O Alliance wants to incorporate IP into the switched-fabric
technology it first proposed last year as a successor to the PCI bus. IP
integration with Future I/O would be a step toward letting enterprises merge
LANs, WANs and storage area networks (SANs) into single,
continent-spanning networks.
Future I/O promises to increase throughput between processors, memory and
I/O. Moreover, the switched-fabric technology gives each device on the fabric
a dedicated 2.5-gigabyte-per-second link to every other device, unlike the
PCI bus, which shares a single 132-megabyte-per-second path among all
devices.
Future I/O's increased throughput will be quite powerful, said Brock Freeman,
information technology director at MILA Inc., a mortgage company.
"I know right now that the CPU is really no longer the bottleneck-I/O is,"
Freeman said. "This type of switched fabric will allow the rest of the computer
to catch up to what the CPU's done over the past couple of years. I think this
will definitely become very attractive to us."
The Future I/O technology is backed by about 70 companies. Last week,
Cisco joined the alliance.
Future I/O sponsors last week said they plan to broaden the specification to
let Future I/O packets encapsulate IP Version 6 packets so that data can
move between server and storage over any IPv6 network. IPv6 is being
incorporated into networking hardware, which would let Future I/O be
deployed on WANs. But IPv4 is the most common version of IP used on the
public Internet, so Future I/O traffic wouldn't be able to ride the Internet at
large. Version 6 enhances security and improves throughput.
The sponsors posted a draft of the Future I/O specification to the Internet last
week. A final spec is due out at year's end, and servers, storage and
networking equipment using Future I/O are expected to ship in mid-2001.
But NGIO, a competing switched-fabric specification with expected shipment
of compliant products next year, could undercut Future I/O.
Intel, Dell Computer and Sun Microsystems are among about 60 vendors
backing NGIO. IP support is not planned, and NGIO connections will be
limited to distances of 17 meters.
While Future I/O and NGIO are both switched-fabric architectures, they
differ in throughput. The raw data speed of NGIO is 2.5 Gbps, compared
with Future I/O's 12.5 Gbps, which translates into usable data bandwidth of
0.475 gigabytes per second for NGIO, compared with Future I/O's 2.5
gigabytes per second, the Future I/O Alliance said.
David Pensak, a senior research fellow at materials and energy giant E.I. du
Pont de Nemours Inc., expects the two standards camps to come to a
compromise.
"I don't think either of them has the muscle to support an incompatible
standard in the face of the opposition," he said. "They'll have to sit down
together."
Future I/O also shares some functionality with Fibre Channel, another
switched-fabric connection for I/O. But Future I/O advocates say that Fibre
Channel will not become obsolete because its larger packet size makes it
better than Future I/O at delivering streaming storage, such as disk-to-tape
backup and for video, audio and other media, said Karl Walker, vice
president of technology development in Compaq's Enterprise Computing
Group. Fibre Channel also has a large installed base that will likely continue to
support the technology.
Joseph Furmanski, manager of systems support for the UPMC Health
System, a network of hospitals and clinics, said connecting storage and
servers to the same network could be problematic. Storage requires
deterministic response times and cannot tolerate dropped packets, two
qualities not supported on many networks.
"One of the strengths of storage area networks is that they are private and
focused on storage, as opposed to sharing bandwidth with PCs and other
networks," Furmanski said.
DuPont's Pensak agreed. He added that merging the storage network, LAN
and WAN also will present security problems. Organizations concerned about
security can now simply shut down their Internet connections, but that won't
be an option if their path to storage is a WAN connection.
"If I'm not running an Internet application now, I know I'm safe, but I won't
know that any longer if my bus backplane is tied directly to the Internet,"
Pensak said.
Although IPv6 adds security at the network level, Pensak said that security
would not extend to the operating system level.
Future I/O advocates acknowledged that the concerns are legitimate. Storage
communication may conflict with other network traffic, but enterprises will
need to decide if the benefits provided by simplified management of a single
network is worth the performance cost. Likewise, applications that require a
great deal of security will not be good candidates for connecting to storage
across a WAN.
Copyright ® 1999 CMP Media Inc.
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