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Chapter 22: Evolution of Intelligent Networks
1. B. Dropping packets as they arrive is called tail drop. Selective dropping of packets during the time queues
are filling up is called congestion avoidance (CA). Cisco uses weighted random early detection (WRED) as a
CA scheme to monitor the buffer depth and performs early discards (drops) on random packets when the
minimum defined queue threshold is exceeded.
2. A, C. You unite switches into a single logical unit using special stack interconnect cables that create a
bidirectional closed-loop path. The network topology and routing information are updated continuously
through the stack interconnect.
3. C. A more efficient use of resources has a cost benefit because less physical equipment means less cost.
What minimizes the spending is the fact that the customer pays only for the services or infrastructure that
the customer uses.
4. B, D, E. Voice traffic is real-time traffic and comprises constant and predictable bandwidth and packet
arrival times. One-way requirements incudes latency < 150 ms, jitter <30 ms, and loss < 1%, and
bandwidth needs to be 30 to 128 Kbps.
5. B. The control plane represents the core layer of the SDN architecture and is where the Cisco APIC-EM
resides.
6. A. Infrastructure as a Service (IaaS) provides only the network and delivers the computer infrastructure
(platform virtualization environment).
7. C. A trust boundary is where packets are classified and marked. IP phones and the boundary between the
ISP and enterprise network are common examples of trust boundaries.
8. A. The IWAN provides transport-independent connectivity, intelligent path control, application optimization,
and highly secure connectivity.
9. A. NBAR is a layer 4 to layer 7 deep-packet inspection classifier. NBAR is more CPU intensive than marking
and uses the existing markings, addresses, or ACLs.
10. C. DSCP is a set of 6-bit values that are used to describe the meaning of the layer 3 IPv4 ToS field. While
IP precedence is the old way to mark ToS, DSCP is the new way and is backward compatible with IP
precedence.
11. A, B. Southbound APIs (or device-to-control-plane interfaces) are used for communication between the
controllers and network devices, which puts these interfaces between the control and data planes.
12. D. Class of Service (CoS) is a term to describe designated fields in a frame or packet header. How devices
treat packets in your network depends on the field values. CoS is usually used with Ethernet frames and
contains 3 bits.
13. D. Although option A is the best answer by far, it is unfortunately false. You will save time working on
autonomous devices, which in turn will allow you more time to work on new business requirements.
14. C. When traffic exceeds the allocated rate, the policer can take one of two actions. It can either drop traffic
or re-mark it to another class of service. The new class usually has a higher drop probability.
15. C, D, F. The SDN architecture slightly differs from the architecture of traditional networks. It comprises
three stacked layers: data, control, and application.
16. C. NBAR is a layer 4 to layer 7 deep-packet inspection classifier.
17. B, D. Southbound APIs (or device-to-control-plane interfaces) are used for communication between the
controllers and network devices. Northbound APIs, or northbound interfaces, are responsible for the
communication between the SDN controller and the services running over the network. With onePK, Cisco
attempting to provide a high-level proprietary API that allows you to inspect or modify the network element
configuration without hardware upgrades. The data plane is responsible for the forwarding of frames or
packets.
18. B, D. Each stack of switches has a single IP address and is managed as a single object. This single IP
management applies to activities such as fault detection, VLAN creation and modification, security, and QoS
controls. Each stack has only one configuration file, which is distributed to each member in the stack. When
you add a new switch to the stack, the master switch automatically configures the unit with the currently
running IOS image and the configuration of the stack. You do not have to do anything to bring up the
switch before it is ready to operate.
19. B. Platform as a Service (PaaS) provides the operating system and the network by delivering a computing
platform and solution stack.
20. C. Software as a Service (SaaS) provides the required software, operating system, and network by
providing ready-to-use applications or software.
21. C. All data that the cloud stores will always be available. This availability means that users do not need to
back up their data. Before the cloud, users could lose important documents because of an accidental
deletion, misplacement, or computer breakdown.
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