Ccna certification Practice Tests

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 36.  B.  Routing protocols such as OSPF and EIGRP would perform their function on the 

control plane since they are controlling the routing of the data plane. The data plane is 

responsible for switching and routing data. Any data that is destined for endpoints is 

switched or routed on the data plane. For example, when one computer pings another, the 

ping is switched and routed on the data plane. The management plane is any mechanism 

that helps in the management of a router or switch. Routing plane is not a term normally 

used to describe data types; therefore, option D is an invalid answer.

 37.  D.  The Cisco Discovery Protocol (CDP) functions on the management plane of the SDN 

model. It helps with management of the routers and switches and does not directly impact 

the data plane. The data plane is responsible for switching and routing data. Any data that 

is destined for endpoints is switched or routed on the data plane. Network plane is not a 

term normally used to describe data types; therefore, option C is an invalid answer. The 

management plane is any mechanism that helps in the management of a router or switch.

 38.  B.  The southbound interface (SBI) directly communicates with the SDN devices. This 

control is done via several different types of SBI protocols, such as OpenFlow, OpFlex, 

and CLI (Telnet/SSH). The northbound interface (NBI) is responsible for allowing 

communication between applications and the core of the controller. The core of the 

controller is the mechanism that connects the NBI to the SBI. Applications hosted on the 

controller interface with the NBI.

 39.  C.  An application program interface (API) is a method the programmer has created to 

allow other programs to communicate with their program. The interprogrammability 

is required when another program wants to share data with the API. Although an API 

allows data transfer, it is not a program specifically written for the transfer of data. 

An API is used for network programmability, but it is not a language for network 

programmability. An API does not allow for a program to be virtualized.

 40.  C.  The northbound interface (NBI) is responsible for allowing communication between 

applications and the core of the controller. Applications therefore directly communicate 

with the core through the northbound interface. The southbound interface (SBI) directly 

communicates with the SDN devices. The core of the controller is the mechanism that 

connects the NBI to the SBI. The Simple Network Management Protocol (SNMP) is used 

for the monitoring and collection of device metrics.

 41.  B.  The data plane is responsible for the routing of packets to specific destinations. The 

control plane would be responsible for the management of the routes for the functional 

routing of packets. The management plane would be responsible for the management of all 

functions of the router. There is no plane called the routing plane; therefore, option D is 

an invalid answer.

 42.  B.  The maximum hop count on fabric switching is a total of 3 hops. When a host 

transmits, it will enter a Leaf switch; the Leaf switch will then forward traffic to the Spine 

switch. The Spine switch will in turn forward traffic to the corresponding Leaf switch and 

to the destination host. Of course, traffic could be 1 hop away, if both hosts are on the 

same Leaf switch. However, the maximum hop count is 3 hops.

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