NETW 250 WEEK 1 FINAL EXAM

Overview

The Week 1 Final Exam for NETW 250 assesses foundational knowledge in networking, particularly focusing on ITU standards, VoIP technologies, and the features and functions of PBX systems. This exam is crucial for understanding the basic principles that underlie more advanced topics in networking and telecommunications.

Question 1: ITU Standard for Public Phone Numbers

The ITU standard that regulates international public phone numbers is E.164.

• Explanation: E.164 is an international numbering plan developed by the International Telecommunication Union (ITU) that defines the format for telephone numbers. This standard ensures that phone numbers are globally unique, enabling seamless international communication. E.164 numbers are typically composed of a country code, a national destination code, and a subscriber number.

Question 2: Call-On-Hold Feature in SIP Phones

The call-on-hold feature or button of an SIP phone will trigger a(n) re-INV (i.e., new INVITE request) message to change the state of the existing VoIP media session.

• Explanation: In SIP (Session Initiation Protocol) telephony, placing a call on hold involves sending a re-INVITE message to the other party. This message changes the session’s state, allowing the media stream to be paused while keeping the signaling connection open. This feature is essential for managing calls in a business environment, where users frequently need to place calls on hold while they consult with colleagues or retrieve information.

Question 3: Unified Communications (UC) Conferencing Systems

Typical UC conferencing systems perform functions such as switching or combining images during a conference or broadcast, authenticating and authorizing a conference party for privacy, and distributing documents via on-demand download or pushed by the host.

• Explanation: Unified Communications (UC) systems integrate various communication tools, including voice, video, messaging, and conferencing. These systems enhance collaboration by providing a single platform for managing different types of communication. The ability to switch between different media, ensure security, and manage document sharing is critical in professional settings where efficiency and data integrity are paramount.

Question 4: Direct Inward Dialing (DID) Features

Which of the following is correct about Direct Inward Dialing (DID)? All of the above.

• Explanation: DID is a telephony feature offered by service providers that allows external callers to directly reach a specific extension within a PBX system without going through an operator or attendant. This feature is beneficial in large organizations where it is impractical for all calls to be manually routed. DID numbers are often unrelated to the local extension numbers, providing flexibility in call management.

Question 5: Early Calling Line Identification (CLID) for 911 Services

For traditional 911 emergency service, the early CLID indicates a physical address without ambiguity when a single-family home is the destination.

• Explanation: CLID is a critical component in emergency services, providing the location of the caller to the Public Safety Answering Point (PSAP). This information is especially crucial in situations where the caller cannot verbally provide their location. In a single-family home, the address associated with the phone line is clear and unambiguous, ensuring that emergency responders can be quickly dispatched to the correct location.

Question 6: Highlights of Next-Generation E911 Service

Next-generation E911 service enables a PSAP to accept text and SMS messages, GPS location information from a caller’s mobile phone, and VoIP calls with the location information in a newly defined field of the SIP INVITE message.

• Explanation: Next-generation E911 services improve the accuracy and efficiency of emergency responses by incorporating modern communication methods and technologies. These enhancements allow emergency services to receive and process various forms of communication beyond traditional voice calls, ensuring that help can be provided even when voice communication is not possible.

Question 7: Location Determination for IP Phones

The information typically used by the 911 management server to resolve the location of an IP phone on an enterprise network is the physical switch port of the phone.

• Explanation: In an enterprise VoIP environment, the location of an IP phone can be determined based on the switch port to which it is connected. This information is critical for emergency services, as it allows them to pinpoint the caller’s exact location within a building, ensuring a swift and accurate response in case of emergencies.

Question 8: Emergency Location Identification Number (ELIN) in 911 Calls

The call server on an enterprise network handles 911 calls by associating the calling phone with its Emergency Location Identification Number (ELIN).

• Explanation: The ELIN is a number assigned to a specific location within an enterprise’s network that corresponds to a particular phone or group of phones. When a 911 call is made, the ELIN is sent to the PSAP, providing precise location information that is crucial for emergency response teams.

Question 9: Faxing Over a Packet Network

Which of the following is a scenario of faxing over a packet network (via VoIP)? All of the above.

• Explanation: Faxing over IP networks can be accomplished through various methods, including real-time faxing with T.38, store-and-forward faxing with T.37, and reverting to traditional T.30 for certain connections. Each method has its own advantages and is chosen based on the specific requirements of the network and the level of integration with existing fax systems.

Question 10: Newer Telephony Features of VoIP

Which of the following is not a newer telephony feature of VoIP? Using a DID number to directly reach a local extension without an attendant.

• Explanation: Newer telephony features made possible by VoIP include advanced functionalities like receiving faxes directly into an email inbox using a public telephone number (E.164). Traditional features like direct inward dialing (DID) are not unique to VoIP and have been available in circuit-switched telephony for many years.