At Light Reading's Big Telecom Event (BTE) Tuesday, I heard chatter about two different carrier executives being really ticked off about Cisco acquiring Tail-f Systems, and that's understandable. The $175 million deal, expected to close by July 31, means Tail-f — whose tools manage configuration and provisioning in multivendor networks — would stop being an independent player.

But Cisco insists it's going to play nice. Less than two years ago, the company acquired Cariden and Intucell, both multivendor companies that have been kept that way so far. Tail-f would likewise continue to serve multivendor networks, and Cisco would continue to serve Tail-f's customers, executives say.

In fact, Tail-f would fit into a multivendor framework of Cisco's — the Evolved Services Platform (ESP), a software-defined networking (SDN) framework for service-provider networks, says Sanjeev Meervana, Cisco's senior director of marketing.

The Application-Centric Infrastructure (ACI) gets most of the Cisco press these days, but it represents a dramatic shift from the way networks are run today, and it's initially emphasizing the data center. Cisco has been pitching ESP as an SDN option for older equipment and the WAN.

ESP consists of three layers. Two of them are a service broker that advertises available services to the end user, and the virtual network functions (VNFs) in the network that would make that service happen.

Between them is an orchestration layer that activates VNFs based on the service's needs. It's an integration job — gathering and stitching together those virtual functions — that service providers could do themselves; ESP hands the job to Cisco.

(Relating it to the NFV silos that Axel Clauberg of Deutsche Telekom warned about in his Tuesday keynote, Cisco claims it's provides an end-to-end NFV management that would ensure NFV remains unified.)

Tail-f, even without getting acquired, can be part of that kind of orchestration. So, what does a carrier customer gain by having Tail-f become part of a larger vendor? The way Cisco sees it, the deal would simplify the use of Tail-f, taking care of integrating Tail-f with the rest of ESP. "We're helping them put that puzzle together," Meervana says.

Multivendor integration would remain a part of Tail-f's mission even under Cisco, because Tail-f can help apply ESP to a multivendor environment, Meervana says. (Technically, ESP could be an orchestration platform for a network that doesn't have any Cisco gear at all, he adds.)

For those who don't want any ESP with their Tail-f, Cisco would presumably keep open the option of using Tail-f independently. Likewise, ESP wouldn't be required to include Tail-f; even after the acquisition, ESP would continue to support other options for orchestration including OpenFlow and the Path Computation Element Protocol (PCEP), Meervana says.

So, that's how Tail-f would fit into the Cisco picture. Whether carriers will be happy about it remains to be seen. For example, it didn't go unnoticed at BTE that Tail-f was included in AT&T's search for new suppliers under Domain 2.0, a program meant to get the carrier more involved with small companies and startups. One could interpret Domain 2.0 as AT&T trying to reduce its dependency on big vendors, but if that's true, Cisco just made it a little harder.