As IT departments look to software-defined networking (SDN) to reduce operating costs and increase business agility, the strengths and drawbacks of different SDN architectures stops becoming an academic debate and starts becoming an actual business decision.
Cisco believes the success of an IT or cloud automation solution depends on the business policies that can be carried out by the infrastructure through the SDN architecture. In a recent post, Cisco Senior Solution Marketing Manager Gary Kinghorn talked about how the company’s Application Centric Infrastructure (ACI) supports a business-relevant application policy language that provides greater scalability and network visibility than systems based on typical SDN architectures.
Kinghorn’s blog is the first of a four-part series that will compare the critical architectural components of Cisco ACI and typical SDN. Rather than centralize network control functions on the SDN Controller as most SDN architectures do, ACI is based on a declarative model that uses the OpFlex southbound API to communicate policies between the controller and various network devices.
Cisco’s approach to SDN is so different that some have debated whether it’s actually SDN at all, but Kinghorn says SDN and Cisco ACI share essentially the same IT automation objectives, we well as some fundamental baseline architectural features:
- Centralized policy store and infrastructure controller: For Cisco ACI, this is the Application Policy Infrastructure Controller (APIC).
- Programmable, or automated, network devices: All infrastructure devices such as servers and network nodes must be able to respond to and implement policies according to commands from the controller.
- Controller southbound protocol: The OpenFlow protocol is typically used in SDN architecture, and vendors have released OpenFlow-compliant switches. In Cisco ACI, OpFlex is the primary protocol.
- Northbound controller interfaces: These integrate higher-level automation solutions on top of the policy and controller framework, including workflow automation tools and analytics.
Kinghorn compares the capabilities allowed in the Cisco ACI policy model to those of existing virtual overlay solutions. Future installments in the series will compare critical protocols and components in Cisco ACI with VMware NSX to contrast Cisco ACI against software overlay networks.