Multiservice Networking, IPX Networking, and Security - CCIE Routing and Switching Exam Certification Guide - page 576

Foundation Summary

The Foundation Summary is a condensed collection of material that provides a convenient
review of key concepts in this chapter. If you are already comfortable with the topics in this
chapter, this summary will help you recall a few details. If you just read the Foundation Topics
section, this review should help solidify some key facts. If you are doing your final preparation
before the exam, these materials are a convenient way to review the day before the exam.

Multiservice Technologies Table 12-7

Technology Description

FXS Foreign Exchange Station

FXO Foreign Exchange Office

E&M Ear and Mouth—analog Trunk

Erlang Total voice traffic volume in one hour

VA D Voice activity detection

RTP Real-Time Transport Protocol—carries coded voice; runs over UDP

RTCP RTP Control Protocol

Codec Coder-decoder—transforms analog signals into digital bit streams

H.323 ITU framework for multimedia protocols

SIP Session initiation protocol—IETF framework for multimedia protocols

SS7 Allows voice and network calls to be routed and controlled by central call

controllers; permits modern consumer telephone services

Codec Standards

Table 12-8

Codec Bit Rate Description

G.711u 64 kbps Pulse code modulation (PCM); mu-law version in North America and Japan.

Samples speech 8000 times per second represented in 8 bytes.

G.711a 64 kbps PCM; a-law in Europe and in international routes.

G.723.1 6.3 kbps MPE-MLQ (Multi-Pulse Excitation-Maximum Likelihood Quantization)

G.723.1 5.3 kbps ACELP (algebraic code-excited linear prediction).

G.726 16/24/ 32/

40 kbps

Adaptive differential pulse code modulation (AD-PCM).

G.729 8 kbps CS-ACELP (Conjugate Structure ACELP).