Brocade Communications Systems' planned US$3 billion acquisition of Foundry Networks is a major strategic move in a brewing war over the future of data-center connectivity, industry analysts said Tuesday.

The deal, expected to close in the fourth quarter, would combine a maker of Fibre Channel SAN (storage area network) switches for data centers and a specialist in enterprise Ethernet LANs, two technologies that are headed toward a merger themselves.

The future of data centers lies with Ethernet, because it's relatively inexpensive, keeps scaling up to higher speeds and is ubiquitous throughout the rest of enterprise networks, analysts say. Virtualization and data-center consolidation are helping to drive the need for Ethernet's growing speeds. The idea is to create a "unified fabric" that spans both the data center at the enterprise's core and the LAN where client systems are located. But there are two main ways to bring Ethernet to data centers with the features needed there.

Both Brocade and Cisco are pushing FCoE (Fibre Channel over Ethernet), an IEEE standard expected later this year that would combine characteristics of both systems. By mapping Fibre Channel traffic over Ethernet networks, it will let enterprises take advantage of Ethernet speeds of 10G bps (bits per second) and up while keeping the latency, security and traffic management benefits of Fibre Channel. FCoE will also smooth the migration to Ethernet by letting the two technologies coexist in a single switch, so existing SANs (storage area networks) can stay.

The alternative is iSCSI, (Internet Small Computer System Interface) which some smaller enterprises have adopted because it can be used with conventional Ethernet switches and without in-house Fibre Channel expertise, said Bob Laliberte of Enterprise Strategy Group. Its main proponents have been storage vendors, he said.

Although it will take years for current Fibre Channel SANs to be replaced, one of the two is likely to win out, analysts said.

"There's a major religious war between FCoE and iSCSI," said Burton Group analyst Dave Passmore. They represent completely different technical approaches to combining Ethernet and storage transport protocols. "Reasonable people will disagree," he said.

Like Fibre Channel, FCoE does not use TCP/IP (Transmission Control Protocol/Internet Protocol), the basic communication protocol of the Internet and Ethernet networks, instead making up for it with other tools. Of the two approaches, only FCoE requires expensive, specialized switches, Passmore said, but it's more attractive to many organizations because it allows for a smoother transition from existing architectures, he said.

Enterprises could eventually lose out by choosing the technology that loses, but FCoE and iSCSI will probably coexist for years, Passmore said.

A unified fabric could save users money as well as complexity, Passmore said. For example, instead of having one network connection to the LAN and another to the SAN that it taps into for data, a blade server could have just one set of connections.

"That would greatly simplify the user's network infrastructure and require fewer switches," Passmore said.

Security is the main potential concern about having a common type of network across data centers and LANs, he said. Having two completely different networks as is traditionally done has built-in security benefits. But costs and benefits always have to be balanced in adopting new technologies, he said.

Brocade's purchase of Foundry will create a second powerful vendor of FCoE, said Yankee Group analyst Zeus Kerravala. So far, Cisco has been the only company with both the vision and the technology to create a unified fabric, he said. Brocade had the vision and now is gaining the Ethernet goods, Kerravala said.

"If the concept of unified fabric really does come true, there are really only two vendors," Kerravala said.