"We're a little bit confused on how they got there," says King. "There are some pieces missing in that comparison."
And Cisco's openness claims regarding ACI are not unique either, Hedlund says. "Open interfaces is just table stakes," he says.
Analysts believe Cisco's ACI may be most challenged in those sites where VMware hypervisors have been entrenched for years for server virtualization.
"The big question will be how customers that have virtualized their data centers, typically with VMware's hypervisor, and that are moving relatively quickly to private/hybrid cloud will respond," says IDC's Brad Casemore. "Much will depend on whether those organizations have reorganized their internal IT constituencies to facilitate the journey to cloud. Are the server/virtualization teams now calling the shots on infrastructure for those organizations? If so, then NSX, as a linchpin of VMware's SDDC, is definitely in the picture.
"VMware...is a long-term threat to Cisco's desire to not only protect its core business, but also to get a bigger share of overall data center expenditures" in compute, networking, storage and management, Casemore says.
Arista is a threat in data center and cloud switching, but the company also believes Insieme underscores a mission it's been on for years before the Cisco spin-in's arrival.
"Insieme is a validation of Arista's direction and strategy for the last five years: merchant silicon and an extensible operating system," says Arista CEO Jayshree Ullal. "Customers will need to decide on a closed path and a best-of-breed path (for data center and cloud fabric networking). There's room for both."
Ullal also criticized Cisco's 40G BiDi optics on the Nexus 9000 as proprietary. These optics are intended to allow users with installed multimode fiber for 10G to use that same cabling as they upgrade to 40G.
Though Ullal acknowledged that multimode 10G is the predominant deployment in data centers, she says single mode fiber should be used for 40G and 100G.
"You don't want to compromise the distance" of 40/100G with multimode fiber, she says. "At 40 km to 100 km, single mode is preferred."
HP is not really on Cisco's radar screen in data center networking. But HP is big into SDNs, especially those based on OpenFlow and the decoupled control and data plane architecture.
HP also views Insieme as responding to the SDN wave with proprietary hardware.
"Cisco ignores the SDN movement and instead seems to continue their focus on creating a hardware-defined' alternative that locks customers into a proprietary Cisco network denying customers the economic and game-changing simplification, automation and application development benefits promised by SDN," states HP Networking CTO Dave Larson.
Larson claims the Nexus 9000 and ACI is incompatible with existing Nexus switches, lacks a migration path for those customers and does not protect those investments. He says ACI is a lock-in to a Cisco-only architecture, while HP's OpenFlow-based SDN switches and controller, and 23-partner ecosystem are designed for HP and non-HP infrastructure.
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