Review Questions

1.	Traditional voice networks typically include which of the following devices or protocols? (Choose all that apply.) VoATM PBX switches Centrex switches H.323 application support
2.	Subscriber signaling is used between which voice network devices? PBX and trunk line Trunk line and tie-line PBX to PBX PBX and telephone
3.	Centrex lines offer which additional services beyond those of a PBX switch? (Choose all that apply.) Call transfer Three-way calling Closed-user dialing plans Signaling System 7
4.	Which of the following methods best handles delay in VoIP networks? Addressing QoS Routing Hardware
5.	What is the responsibility of the codec in voice networks? (Choose all that apply.) It encrypts the voice traffic. It decrypts the voice traffic. It compresses the voice traffic. It decompresses the voice traffic.
6.	Which of the following best describes variable delay? Delay Jitter QoS Packet loss
7.	Which solution can help smooth voice traffic that has been affected by jitter? Codec IP telephony Dejitter buffer None of the above
8.	Cisco’s SAFE architecture blueprint design model addresses what network requirements? Performance Equipment Security Administration
9.	Which devices would you expect to find in the Corporate Internet module of a SAFE-designed network? (Choose all that apply.) End-user workstations Intranet servers VPN access Internet services
10.	Which devices would you expect to find in the Campus functional area of a SAFE-designed network? (Choose all that apply.) E-Commerce servers Management servers VPN access Intranet servers
11.	Where would you typically find a firewall in a SAFE-designed network? Internet Connectivity module Campus Service Provider Edge None of the above
12.	Which devices of a network are targets for security exploitation? (Choose all that apply.) Hubs Servers Routers and switches Applications
13.	What can be placed on a host or network to act like an alarm system if security issues should arise? TFTP server IDS FTP server Syslog server
14.	When designing security for the E-Commerce module, which of the following are common countermeasures to typical security issues in this module? (Choose all that apply.) IDS Firewalls Host hardening DMZ networks All of the above None of the above
15.	Which type of server can be used to log security-related information from network devices? TFTP Telnet FTP Syslog
16.	When capturing security-related information to a Syslog server, which protocol provides accurate time reporting? NTP FTP IDS HTTP
17.	Which of the following is an outsourced service? PSTN Centrex PBX QoS
18.	Which SAFE technology is most effective at preserving data confidentiality? IDS Encryption Authentication QoS
19.	What is the first step in any secure network security design? Cisco’s SAFE architecture blueprint Security policy Education Manager’s approval
20.	This type of network attack can render a host unreachable by valid requests. IDS DoS SNMP Flood

Answers

1.	B, C Traditional voice networks typically include PBX and Centrex switches. They also include tie-lines and trunks.
2.	D Subscriber signaling is used between the PBX and the telephone.
3.	A, B, C Centrex lines offer additional services such as call transfer, three-way calling, and closed-user plans.
4.	B Delay in VoIP networks is handled by QoS.
5.	C, D The codec is responsible for compressing and decompressing voice traffic. Codec choice determines the transfer rate.
6.	B Jitter is defined as variable delay.
7.	C Dejitter buffers can receive packets at an irregular rate and send them out at a more consistent rate.
8.	C The purpose of Cisco’s SAFE architecture blueprint design model is to address the network’s security requirements.
9.	C, D Cisco’s SAFE architecture design blueprint recommends that VPN access and Internet services be placed in the Corporate Internet module.
10.	B, D Cisco’s SAFE architecture design blueprint recommends that management and intranet servers, along with end-user workstations, be placed in the Campus functional area.
11.	A Cisco’s SAFE architecture design blueprint recommends that firewalls be placed in the Internet Connectivity module.
12.	B, C, D Servers, routers, switches, and applications are all targets for security exploitation. Hubs are not generally a risk because of their lack of management features.
13.	B Although a Syslog server is typically used to log security data, only the IDS actually acts like an alarm system.
14.	E E-Commerce modules are similar to Internet Connectivity modules; both employ IDS, firewalls, host hardening, and DMZ networks.
15.	D A Syslog server is the preferred server to log security-related information from network devices and IDSs.
16.	A The NTP (Network Time Protocol) provides for accurate time reporting when configured on each network device and a central server.
17.	B Centrex is a service purchased, generally on a monthly fee, to provide services commonly provided by a PBX.
18.	B Encryption can help keep data confidential.
19.	B Every secure network security design starts with a security policy relevant to the organization.
20.	B A DoS (denial-of-service) attack can render a host unreachable by valid requests and cause network slowdowns.