Ccna certification Practice Tests

390

 

Appendix 

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  Answers to Practice Test Questions

 3.  A.  When a firewall matches a Uniform Resource Identifier (URI), such as a URL, it 

is operating at layer 7. This is known as a web application firewall, or WAF. Layer 5 

communications are session based; one such application that is session based is Structured 

Query Language (SQL). Layer 4 communications are port based; many basic firewall rules 

are built to block and allow specific ports. Layer 3 communications are IP address based; 

many basic firewall rules are also built to block and allow specific IP addresses.

 4.  A.  An autonomous WAP acts similarly to an access layer switch. However, WAPs 

normally do not have redundant links back to the distribution switches. So it acts more 

like a star topology, connecting the Ethernet and wireless clients together. A full mesh 

topology is often found between the core and distribution layers of the Cisco three-tier 

design model. A partial mesh topology is often found between the distribution and access 

layers in the Cisco three-tier design model. A hybrid topology is found in many networks 

today because one topology does not fit all needs throughout the network.

 5.  B.  High-Level Data Link Control (HDLC) is the default encapsulation on a serial 

connection for Cisco. Multiprotocol Label Switching (MPLS) is becoming a popular WAN 

connectivity method, but it is not an encapsulation method. Point-to-Point Protocol (PPP) 

is an open standard layer 2 protocol used for point-to-point connections, such as WAN 

serial connections. Point-to-Point Protocol over Ethernet (PPPoE) is the PPP protocol 

encapsulated into an Ethernet frame. Its most notable use is in Digital Subscriber Line 

(DSL) communications, where it is mainly used for its authentication methods.

 6.  B.  The Point-to-Point Protocol (PPP) is an open standard. Cisco routers default to the 

HDLC protocol. However, HDLC is a proprietary standard for Cisco. So PPP should be 

used for compatibility. Point-to-Point Protocol over Ethernet (PPPoE) is the PPP protocol 

encapsulated into an Ethernet frame. The X.25 protocol is one of the first WAN protocols 

for packet switching; it has largely been deprecated for newer protocols, such as PPP, that 

offer more features.

 7.  C.  The central office, sometimes referred to as the CO, is the local switching office. The 

CO is where your data lines meet the public network for data and voice. The demarcation 

point, or demarc as it is also referred to, is the point at which the provider responsibility 

for wiring and maintenance ends. Network edge is not a term typically used for WAN 

networking; therefore, it is an invalid answer. The main data frame (MDF) describes the 

location where network equipment is concentrated and connects to external networks.

 8. B. Point of presence (PoP) is the term that defines the access point of the provider’s 

services. These services might be Internet, private WAN, or cloud resources. The 

demarcation point, or demarc as it is also referred to, is the point at which the provider 

responsibility for wiring and maintenance ends. Customer edge is a term often used with 

Multiprotocol Label Switching (MPLS) WAN terminology to describe the end of the 

customer’s network before a packet enters the MPLS network. Network edge is not a term 

typically used for WAN networking; therefore, it is an invalid answer.

 9.  C.  Lowering bandwidth between the premises and your virtual machines (VMs) on 

the public cloud is a direct benefit of locating a Network Time Protocol (NTP) virtual 

network function (VNF) on the public cloud for VM time synchronization. Using an NTP 

server regardless of where it is located will yield you precision time. Implementing the 

NTP VNF in the cloud will not allow for better response time from VMs. An NTP VNF 

will not overcome different time zones; this is a function of the time offset on the VM.

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Chapter 7: Practice Exam 1