Blogs about: Cisco Voip Implementations
Featured Blog
With QoS feature in place, there can be up to 10 concurrent VoIP calls over a company WAN link. Is there need for CAC? With no CAC, what will happen when there are more than 10 concurrent calls?
Yes, CAC compliments QoS configurations so that WAN bandwidth does not get oversubscribed. With no CAC over 10 concurrent calls, packets will be dropped indiscriminately and experience poor voice qual… more →
Andy's Cisco Exam Notes
With QoS feature in place, there can be up to 10 concurrent VoIP calls over a company WAN link. Is there need for CAC? With no CAC, what will happen when there are more than 10 concurrent calls?
engineeringtop wrote 1 year ago: Yes, CAC compliments QoS configurations so that WAN bandwidth does not get oversubscribed. With no C … more →
What is CAC?
engineeringtop wrote 1 year ago: Call Admission Control is a feature that is configured to limit the number of concurrent calls. CAC … more →
List at least 3 voice gateway functions on a Cisco router
engineeringtop wrote 1 year ago: On a Cisco router, voice gateway functions include the following: Connect traditional telephony devi … more →
List at least three important components of enterprise voice implementations.
engineeringtop wrote 1 year ago: gateway gatekeeper Call Manager Cisco IP Phones … more →
What is VAD?
engineeringtop wrote 1 year ago: VAD stands for Voice Activity Detection and is a feature available in voice-enabled networks. It sup … more →
Briefly list the steps necessary to compute the total bandwidth for a VOIP call.
engineeringtop wrote 1 year ago: Determine the codec and the packetization period Determine link-specific information (cRTP, Layer 2 … more →
Name at least three tunneling and security protocols and their associated overhead?
engineeringtop wrote 1 year ago: IPsec transport mode 30 to 53 bytes IPsec Tunnel mode 50 to 73 bytes L2TP … more →
What are the sizes of Ethernet, 802.1Q, Frame-Relay, and Multilink PPP (MLP) overhead?
engineeringtop wrote 1 year ago: Ethernet 18 bytes 802.1Q 22 bytes Frame Relay 6 bytes Multilink PPP (MLP) 6 bytes … more →
What is the relationship between packet rate and packetization period?
engineeringtop wrote 1 year ago: The Packet rate and Packetization period are reciprocal. For example, if the packetization period is … more →
List at least three factors that influence bandwidth requirements of VOIP?
engineeringtop wrote 1 year ago: packet rate and packetization size IP overhead Data link overhead Tunneling overhead *Packetization … more →
What is cRTP?
engineeringtop wrote 1 year ago: Compressed RTP (cRTP) or RTP Header Compression. cRTP reduces the IP, UDP, and RTP headers from 40 … more →
What feature does RTP provide to complement UDP?
engineeringtop wrote 1 year ago: RTP provides Sequence Numbering (Reordering) and Time Stamping. … more →
Which TCP/IP protocols are responsible for transporting voice? What are the sizes of these protocol headers?
engineeringtop wrote 1 year ago: IP 20 bytes UDP 8 bytes RTP 12 bytes … more →
What is a DSP?
engineeringtop wrote 1 year ago: Digital Signal Processor – processors on voice gateways. They provide voice termination, trans … more →
What is MOS?
engineeringtop wrote 1 year ago: Mean Opinion Score is an ITU Standard technique used for measuring of voice codecs. MOS values whic … more →
Name at least 3 main codec/compression standards and specify their bandwidth requirements
engineeringtop wrote 1 year ago: G.711 (PCM) 64Kbps G.726 (ADPCM) 16, 24, 32 Kbps G.728 (LDCELP) 16Kbps G.729 (CS-ACELP) 8Kbps G.729- … more →
Name and explain the quantization methods used in North America and other countries
engineeringtop wrote 1 year ago: Two variations of logarithmic quantization exist: μ-law and A-Law. Bell developed μ-law and it is … more →
What are the two main quantization techniques?
engineeringtop wrote 1 year ago: Linear quantization and logarithmic quantization … more →
List the steps for converting digital signals to analog signals
engineeringtop wrote 1 year ago: Decompression (optional) Decoding and FILTERING Reconstructing the analog signal … more →
