Chapter 12: Voice and Video Over IP

____ is a measure of how well a network service matches its expected performance.

QoS

Attempts to reserve a specific amount of network resources for a transmission before the transmission occurs.

RSVP

Helps voice and video networks overcome UDP's shortcomings.

RTP

____ signaling functions are more limited than those performed by the protocols in the H.323 group.

SIP

When using an analog telephone, a VoIP adapter that performs analog-to-digital conversion is known as a(n) ____.

ATA (analog telephone adapter)

____ is the use of one network to simultaneously carry voice, video, and data communications.

Convergence

All VoIP calls are carried over the Internet.

False

IP telephones are directly connected to the local loop.

False

SIP and H.323 account for communication between media gateways.

False

When VoIP relies on the Internet, it is often called ____.

Internet Telephony

IPTV, videoconferencing, streaming video, and IP multicasting belong to the range of services known as ____.

video over IP

The H.323 protocol that handles call or videoconference signaling.

H.225

Ensures that the type of information issued to an H.323 terminal is formatted in a way that the H.323 terminal can interpret.

H.245

The nerve center for networks that adhere to H.323.

H.323 gatekeeper

A device providing translation between network devices running H.323 signaling protocols and devices running other types of signaling protocols.

H.323 gateway

Any node that provides audio, visual, or data information to another node.

H.323 terminal

A collection of H.323 terminals, gateways, and MCUs that are managed by a single H.323 gatekeeper.

H.323 zone

____ describes the use of any network to carry voice signals using the TCP/IP protocol.

IP telephony

In general, a(n) ____ is a private switch that accepts and interprets both analog and digital voice signals.

IP-PBX

A computer that provides support for multiple H.323 terminals and manages communication between them.

MCU (multipoint control unit)

Many network engineers consider ____ to be superior to MGCP.

MEGACO

A(n) ____ is a computer that manages multiple media gateways.

MGC

____ messaging is a service that makes several forms of communication available from a single user interface.

Unified

An off-the-shelf workstation can be programmed to act like an IP telephone.

True

It is more difficult to transmit VoIP and video over IP signals over a packet-switched network than it is to transmit data signals.

True

____ is preferred over TCP for real-time applications such as telephone conversations and videoconferencing.

UDP

When more than two people participate in a videoconference, for example, in a point-to-multipoint or multipoint-to-multipoint scenario, a video ____ is required.

bridge

SIP and H.323 regulate ____ for VoIP or video-over-IP clients and servers.

call signaling and control

One drawback to ____ video is that content may not be edited before it's distributed.

live streaming

When a caller uses an IP telephone, his or her voice is immediately digitized and issued from the telephone to the network in ____ form.

packet

A computer programmed to act like an IP telephone is known as a(n) ____.

softphone

The popular Internet telephony software, Skype, is a type of ____.

softphone

Among all video-over-IP applications, ____is perhaps the simplest.

streaming video

Using VoIP over a WAN allows an organization to avoid paying long-distance telephone charges, a benefit known as ____.

toll bypass

Many streaming video services - and nearly all of those issued over a public network, such as the Internet - are examples of ____ transmissions.

unicast