Flatten your network to consolidate data centers

Will the flattening of data center networks help government agencies in their consolidation and cloud computing efforts?

Network consolidation — or flattening — is not the only component, but it is a key element of simplifying data center operations and improving performance, some industry experts say.

Data center networks are driven by innovations in automation, virtualization and fabric technologies aimed at improving operations and cutting capital expenditures, they say. Furthermore, the push for improvements in information technology operations and cost savings are driving the federal government’s cloud computing and data center consolidation initiatives.

When organizations consolidate data centers and virtualize servers, they are going to have more traffic in the consolidated area, said Jon Oltsik, a senior principal analyst at the Enterprise Strategy Group.

“So it is beneficial at that point to consolidate the network as well,” he added.

That means reducing the number of tiers, adding multiple devices that can look like one device and aggregating traffic — all of which simplifies operations and ensures that network performance and latency are at acceptable levels, Oltsik said.

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Cisco Systems has been pushing the concept for more than a year, and Juniper Networks recently jumped on the bandwagon.

“Converging data and networking into a fabric allows the use of reusable pools of resources,” which is preferable to fixed resources that cannot be shared, said Chris Hoff, director of cloud and virtualization solutions at Cisco.

For instance, Cisco's Unified Computing System combines computing, storage and network access into a single network, and the Cisco Nexus 7000 series, a modular switching system, provides 10 Gigabit Ethernet and unified fabric for data centers, Hoff said.

Most data centers have architectures in which traffic flows from remote client systems to servers at the data center, said Tim LeMaster, director of systems engineering at Juniper.

However, with the advent of server virtualization — the ability to run multiple instances of operating systems concurrently on a single hardware system — communication patterns have changed so that a lot of traffic travels from server rack to server rack as applications move from one virtualized server to another, LeMaster said.

“The data center hasn’t changed to accommodate this change,” he added. Data center architecture is basically made up of access, aggregation, distribution and core layers, LeMaster said. It is an inefficient layout because it requires a high number of ports to sit idle so the network can accommodate traffic and connectivity between the various layers, he said.

To address that inefficiency, Juniper is offering a 3-2-1 data center network architecture that lets organizations flatten and simplify existing data center networks, LeMaster said. By using Juniper’s Virtual Chassis fabric technology, data center managers can reduce their network from three to two layers now and then collapse to one layer via Juniper's Project Stratus fabric in the future.

With the Virtual Chassis, users can put an Ethernet switch at the top of the server rack and connect all the rack switches together to act as one Ethernet switch. That approach simplifies the network because traffic does not have to traverse the entire hierarchy to move from rack to rack, LeMaster said.

Ultimately, IT managers would need fewer layers of equipment and switches. Additionally, they could better accommodate lower latency and reduce network jitter, he said. The Virtual Chassis supports Juniper’s new 10 Gigabit Ethernet switch.

In the meantime, the Defense Information Systems Agency and the Interior Department’s National Business Center are offering cloud computing services to the Defense Department and civilian agencies, respectively. To do that, they need to connect large numbers of servers and would eventually need a more consolidated, less complex network, Oltsik said.

Flattening network switches is a valid approach, but it only addresses one aspect of the next-generation data center, which must have networks that can scale to accommodate the move from private clouds to more hybrid models, Cisco’s Hoff said.