- Understanding the Theory of Voice VLANs
- Configuring Voice VLANs
- Power over Ethernet
- Essential Network Services: DHCP and NTP
- Understanding the Phone Bootup Process
- Installing Cisco IP Phone Firmware and XML Configuration Files
- Exam Prep Questions
- Answers to Exam Prep Questions
- Suggested Reading and Resources
Answers to Exam Prep Questions
A and E. 802.1Q is a standards-based trunking protocol and shares a single physical connection for voice and data traffic. End users typically are not permitted to access the network over multiple VLANs, so answer B is incorrect. Answer C is incorrect; VLANs isolate traffic at Layer 2. Multiple VLANs are not used for load balancing because end stations can only access one VLAN at a time, so answer D is incorrect.
C. Broadcast storm describes the endless flooding of frames in a Layer 2 switched environment. Answers A, B, and D are incorrect. None of those terms have meaning in the Ethernet switch environment.
C. The encapsulation command followed by the encapsulation type and the VLAN number. Answers A and B are incorrect; the answers are in global mode, not interface mode. Answer D has the parameters of the encapsulation command backward.
C. Deploy IP phones using DHCP. Statically applying IP addresses is time consuming and error prone, so answer A is incorrect. Using public IP addresses for phones opens a security threat, so answer B is incorrect. Answer D is incorrect; the goal is to separate voice and data traffic.
A. No direct connection to the DHCP server. The IP phone DHCP request is a broadcast, so answer B is incorrect. The IP phone uses standard DHCP services, so answer C is incorrect. If the DHCP server is directly attached to the same IP subnet or VLAN, there is no reason to use DHCP relay, so answer D is incorrect.
D. TFTP is used to provision Cisco IP phones. HTTP, DHCP, and FTP are not used during the automatic provisioning and registration process, so answers B, C, and D are incorrect.
A, B, and E. NTP is the source for syslog and CDR time stamps, and for Cisco Unified Communications call agent synchronization. NTP is not used during TFTP downloads to minimize errors, so answer C is incorrect. The time displayed on the IP phones comes from the call agent, so answer D is incorrect. There are many free-access NTP servers on the Internet that have atomic clocks and are typically used as NTP sources, so answer F is incorrect.
C and E. SEP<12 hex digit MAC address>.cnf.xml and XMLDefault.cnf.xml (case sensitive) are valid files. Answer A is incorrect; file requests are case sensitive and the d in default is lowercase. Answer B is an invalid filename and is incorrect. Answer D has only 11 hex digits for the MAC address, not the normal 12, and is incorrect.
B. The complete filename using the TFTP protocol. FTP service is not supported for firmware upgrades, so answer A is incorrect. The complete filename including extension must be referenced by the tftp-server command. The full directory and filename must be defined, not default locations.
A and C. Layer 3 devices can provide DHCP services. Answer B is incorrect; IP phones cannot provide DHCP services. Answer D is incorrect; Layer 2 devices cannot provide DHCP services.