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[techbooks] REVIEW: "IP Telephony", Olivier Hersent/David Gurle/Jean-Pierre

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  • Rob Slade, doting grandpa of Ryan and Tr
    BKIPTLPH.RVW 20000216 IP Telephony , Olivier Hersent/David Gurle/Jean-Pierre Petit, 2000, 0-201-61910-5 %A Olivier Hersent book@netcentrex.net %A David
    Message 1 of 1 , Mar 29 8:19 AM
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      BKIPTLPH.RVW 20000216

      "IP Telephony", Olivier Hersent/David Gurle/Jean-Pierre Petit, 2000,
      0-201-61910-5
      %A Olivier Hersent book@...
      %A David Gurle
      %A Jean-Pierre Petit
      %C P.O. Box 520, 26 Prince Andrew Place, Don Mills, Ontario M3C 2T8
      %D 2000
      %G 0-201-61910-5
      %I Addison-Wesley Publishing Co.
      %O 800-822-6339 617-944-3700 Fax: (617) 944-7273 bkexpress@...
      %P 456 p.
      %T "IP Telephony: Packet-Based Multimedia Communications Systems"

      The preface does a rather heavy-handed sell on IP telephony, without
      really backing up any claims. It doesn't really define a specific
      audience, although the set of people who are listed as possibly being
      interested is a fairly limited one.

      The preface also expects a strong familiarity with ISDN (Integrated
      Services Digital Network) and TCP/IP networking. I'm not sure that I
      understand the requirement for ISDN, but a strong technical background
      is a must, if you are going to tackle this book. The authors don't
      appear to have made much attempt to ensure that it is readable, or
      even lucid. The text resembles nothing so much as a mass of technical
      trivia, only nominally organized. Ironically, despite the heavy
      technical content, there does not seem to be enough detail in the work
      to ensure that even dedicated readers will be able to produce some
      kind of implementation.

      Section one supposedly talks about application layer IP telephony
      protocols, although much of the material appears to be more
      appropriate to the session layer. Chapter one is huge, touching on
      the H.323 standard, RTP (Real-time Transfer Protocol), security,
      codecs, and an extensive H.323 session walk-through. The alphabet
      soup is thick, and not always defined. RAS (Registration,
      Application, Status, in this case) is not expanded at any point prior
      to page six, where it is used for the first time and noted as being
      defined "above," although it is based on H.225.0 which gets mentioned
      "above." H.323 is a complex standard which is somewhat non-standard,
      but the lack of any logical progression in the writing is not going to
      help the reader follow the material. The Session Initiation Protocol
      (SIP), in chapter two, appears to be something of an Internet-based
      contender to the ITU's (International Telecommunications Union) H.323.
      The Media Gateway Control Protocol (MGCP) seems to be a broader
      technology in some competition and cooperation with both, in chapter
      three.

      Section two looks at voice technology. Chapter four touches on a
      number of topics related to voice quality, but mostly concentrates on
      delay. Lots of math, tables, and flowcharts fail to explain much
      about voice coding in chapter five, which primarily seems to be a
      historical progression of standards.

      Section three discusses the network. Chapter six talks about quality
      of service (again emphasizing delay). Network dimensioning, in
      chapter seven, provides lots of math for figuring out the minimum
      bandwidth you need. IP multicast routing is the topic of chapter
      eight.

      Ultimately, this book might be most useful as a pointer to other
      sources of information, such as the standards themselves.

      copyright Robert M. Slade, 2000 BKIPTLPH.RVW 20000216

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