What is VOIP?

What is VOIP?

• A method of delivering voice and multimedia communications over the internet
• A method of segregating multiple networks over the same physical infrastructure
• A platform that allows you to manage virtual machine on a host
• A telephone answering machine and call returning service offered by telecoms providers

EXPLANATION

Voice over Internet Protocol (also voice over IP, VoIP or IP telephony) is a methodology and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet.
The terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the provisioning of communications services (voice, fax, SMS, voice-messaging) over the public Internet, rather than via the public switched telephone network (PSTN).

SOURCE

https://en.wikipedia.org/wiki/Voice_over_IP

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Which one of the following is a common problem that plagues VoIP?

Which one of the following is a common problem that plagues VoIP?

• Buffers
• Critters
• Bitters
• Jitters

EXPLANATION

Jitters, they're not just for coffee addicts anymore. Because the information is divided into packets, each packet can travel by a different path from the sender to the receiver.
When packets arrive at their intended destination in a different order then they were originally sent, the result is a jitter, a call with poor or scrambled audio.

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Which of the following are Fax over IP Protocol(s)?

Which of the following are Fax over IP Protocol(s)?

• t.38
• H.323 and H.404
• M.16 and M.204
• k.30 and k.38 

 

EXPLANATION

The T.38 fax relay standard was devised in 1998 as a way to permit faxes to be transported across IP networks between existing Group 3 (G3) fax terminals. T.4 and related fax standards were published by the ITU in 1980, before the rise of the Internet. In the late 1990s, VoIP, or Voice over IP, began to gain ground as an alternative to the conventional Public Switched Telephone Network. However, because most VoIP systems are optimized
(through their use of aggressive lossy bandwidth-saving compression) for voice rather than data calls, conventional fax machines worked poorly or not at all on them due to the network impairments such as delay, jitter, packet loss, and so on. Thus, some way of transmitting fax over IP was needed.

SOURCE

https://www.3cx.com/pbx/foip/

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What are the tones called when you press a key on your telephone?

What are the tones called when you press a key on your telephone?

• Multiple Frequency Tone Signal
• Dual Signal Tone Frequency
• Dual Tone Multiple Frequency (MF4)
• Single Tone Frequency 

EXPLANATION

DTMF (dual tone multi-frequency) is the beeping signal to the phone company that you generate when you press an ordinary telephone's touch keys.

https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling

SOURCE

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Which one of these is NOT a VoIP protocol?

Which one of these is NOT a VoIP protocol?

• H.248
• MXLP
• SRTP
• SIP 

 

EXPLANATION

SIP, SRTP, and H.248 are all valid VoIP proptocols. MXLP, however, just sounds cool.
https://www.packetizer.com/ipmc/papers/understanding_voip/voip_protocols.html

SOURCE

https://www.packetizer.com/ipmc/papers/understanding_voip/voip_protocols.html

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Which are Fax over IP Protocols?

Which are Fax over IP Protocols?

• k.30 and k.38
• M.16 and M.204
• H.323 and H.404
• t.30 and t.38 

 

EXPLANATION

t.30 and t.38 are fax over ip protocols

SOURCE

https://www.3cx.com/pbx/foip/ 

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Which of the following protocols is not directly related to VOIP?

Which of the following protocols is not directly related to VOIP?

• Real-time Transport Protocol (RTP)
• Session Initiation Protocol (SIP)
• File Transfer Protocol (FTP)
• Inter-Asterisk eXchange (IAX) 

 

EXPLANATION

Voice over Internet Protocol (also voice over IP, VoIP or IP telephony) is a methodology and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet.
Voice over IP has been implemented in various ways using both proprietary protocols and protocols based on open standards. VoIP protocols include:

Session Initiation Protocol (SIP) H.323Media Gateway Control Protocol (MGCP) Gateway Control Protocol (Megaco, H.248) Real-time Transport Protocol (RTP) Real-time Transport Control Protocol (RTCP) Secure Real-time Transport Protocol (SRTP) Session Description Protocol (SDP) Inter-Asterisk eXchange (IAX) Jingle XMPP VoIP extensions Skype protocol

SOURCE

https://en.wikipedia.org/wiki/Voice_over_IP

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Which codec requires a license to use?

Which codec requires a license to use?

• H.323
• G.722
• G.711
• G.729 

 

EXPLANATION

G.729 is a paid and licensed codec

SOURCE

https://nexbridge.co.uk/what-is-the-difference-between-g711-g729-and-gsm-and-why-does-the-codec-matter/

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In a Cisco Unified Communications environment, which of the following CLI commands would you use to restart a cluster?

In a Cisco Unified Communications environment, which of the following CLI commands would you use to restart a cluster?

• utils cluster restart
• utils system restart
• utils system showdown
• system utils restart 

 EXPLANATION

Run the CLI command utils system shutdown or the command utils system restart.
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/10x/os_administration/guide/10xcucosag...

SOURCE

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/10x/os_administration/guide/10xcucosagx/10xcucosag050.html

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Which of the following is NOT involved in recording the audio or video streams in a VoIP call

Which of the following is NOT involved in recording the audio or video streams in a VoIP call

• SPAN
• SNMP
• SIP
• SMDR 

 EXPLANATION

SNMP (Simple Network Management Protocol) is a standard Internet protocol used for collecting and analysing information about devices on a network and configuring network devices.
For more information, see: https://technet.microsoft.com/en-gb/library/cc776379(v=ws.10).aspx
SMDR (Station Message Detail Recording) allows detailed information regarding VoIP phone calls to be sent to a recording device.
See: https://downloads.avaya.com/elmodocs2/merlin/r1_5/html/features/smdr/1.htm
SIP (Session Initiation Protocol) is a communications protocol for signalling and controlling multimedia comms sessions, and is a commonly used VoIP protocol,
SPAN (Switched Port ANalyser), is sometimes called Port Mirroring, and is a mechanism used within Ethernet switches to select specific network traffic and send a copy for analyse to a device on a specific port. For call recording this would be used to capture the actual voice content component of the call.
See: https://www.miarec.com/faq/what-is-port-mirroring

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