Network Architectures for the Data Center: SDN and ACI

In Chapter 10, “Network Architectures for the Data Center: Unified Fabric,” you learned about a series of technological innovations that Cisco amalgamated into a highly successful data center network architecture: Cisco Unified Fabric. Although such architecture has become a primary driver for the evolution of numerous data centers worldwide, it is essentially based on concepts and abstractions that were conceived during the 1970s and 1980s, as the Internet was being formed.

During the last half of the 2000s, inspired by the noticeable differences between networking and other computer systems, a group of researchers began to question whether established networking practices were actually appropriate for the future of IT. Through creativity and healthy naïveté, these researchers proposed many breakthrough new approaches to disrupt well-known network designs and best practices. These new approaches have been collectively given the umbrella term Software-Defined Networking (SDN).

As the world-leading networking manufacturer, Cisco has actively participated in developing the large majority of these cutting-edge approaches, while also creating many others. Combining innovation and intimate knowledge about customer demands, Cisco conceived a revolutionary data center network architecture called Cisco Application Centric Infrastructure (ACI). Specially designed for data centers involved in cloud computing and IT automation, ACI addresses many challenges that were overlooked by earlier SDN approaches.

As mentioned in Chapter 10, the CLDFND exam requires knowledge about two other Cisco data center networking architectures besides Cisco Unified Fabric: Software-Defined Networking and Cisco Application Centric Infrastructure. This chapter focuses on both, exploring the dramatic paradigm shifts they have caused in data center infrastructure and cloud computing projects.

“Do I Know This Already?” Quiz

The “Do I Know This Already?” quiz allows you to assess whether you should read this entire chapter thoroughly or jump to the “Exam Preparation Tasks” section. If you are in doubt about your answers to these questions or your own assessment of your knowledge of the topics, read the entire chapter. Table 11-1 lists the major headings in this chapter and their corresponding “Do I Know This Already?” quiz questions. You can find the answers in Appendix A, “Answers to Pre-Assessments and Quizzes.”

Table 11-1 “Do I Know This Already?” Section-to-Question Mapping

1. Which of the following is not a challenge data center networks bring to cloud computing?

   1. Scalability

   2. Provisioning model

   3. Resource decommission

   4. VLAN ID depletion for tenant isolation

   5. I/O consolidation

2. Which of the following options is not directly related to SDN?

   1. “Clean Slate” program

   2. OpenStack

   3. Network programmability

   4. Provisioning agility

3. Which of the following is not a generic network controller objective?

   1. Exclusively deploy the control plane of a network

   2. Network abstraction for simpler provisioning

   3. Aggregation of device information

   4. Single point of access for provisioning

4. Which of the following correctly define the network planes? (Choose all that apply.)

   1. The data plane corresponds to all processes related to the transport of data packets in a network device.

   2. The control plane makes the decisions that the data plane carries out.

   3. The data plane makes the decisions that the control plane carries out.

   4. The control plane takes care of all communications between network devices in traditional networks.

   5. The control plane is represented through software running on general-purpose CPUs, while the data plane is executed on specialized ASICs.

5. Which of the following is not a valid action for an OpenFlow network device?

   1. Send to SDN controller

   2. Send to egress interface

   3. Send to all ports except ingress

   4. Check TCP flags

   5. Send to input port

6. Which of the following is the main function of SAL in OpenDaylight?

   1. Provide abstraction for southbound protocols

   2. Directly configure OpenFlow compatible devices

   3. Handle REST API calls

   4. Clustering

   5. GUI

7. Which of the following is not an ACI component?

   1. Nexus 9000

   2. APIC

   3. AVS

   4. Nexus 1000V

   5. Partner ecosystem

8. Which of the following contains constructs that are not part of the ACI policy model?

   1. Context, tenant, subnet

   2. Broadcast domain, context, connectivity profile

   3. Contract, filter, subject

   4. Service chain, contract, EPG

9. Which of the following is not a function of APIC?

   1. Control plane

   2. Policy

   3. GUI

   4. Fabric management

   5. API

10. 10. Which of the following are benefits from Cisco Application Centric Infrastructure? (Choose all that apply)

    1. Distributed default gateway

    2. VM provisioning

    3. Encapsulation normalization

    4. Multi-hypervisor integration

    5. Separation of control and data planes