Has much changed in the book since the 2nd edition?
Yes. Over 75% is different. It is almost a brand new book.
What is the biggest change?
The second edition was based on the seven-layer OSI reference model.
The third edition is based on a five-layer model much closer in spirit to
the TCP/IP reference model.
What model is the book now based on?
The model used is a hybrid, incorporating the best features of other
models. This model is shown below:
The difference between this model and the TCP/IP model is that this model distinguishes the physical layer from the data link layer; the TCP/IP model does not. That difference is important. The physical layer deals with topics like the difference between copper wire, fiber optics, wireless LANs, cellular radio, and satellites, whereas the data link layer deals with the concept of point-to-point protocols. These subjects are quite distinct and should not be lumped together. Thus the model the book uses is the TCP/IP model with the "Host-to-network" layer split into a physical layer and a data link layer to give five layers instead of four.
What is the structure of the Third Edition?
First an introductory chapter, then one chapter per layer (including the
MAC sublayer), like last time. Thus structurally, the book still follows
a layered model, which was very successful. Only the model is now essentially
a refined version of the TCP/IP model, instead of the OSI model.
What material is new to the Third Edition?
The material on wireless transmission, Broadband ISDN, low-orbit satellites,
IEEE 802.6, fast Ethernet, HIPPI, fibre channel, distance vector routing,
link state routing, multicast routing, traffic shaping, network performance,
DNS, SNMP, the World Wide Web, multimedia, video on demand, and the MBone
is all brand new. Also, the new running examples throughout the book are
the Internet and ATM networks, with wireless networks discussed where
relevant.
What material from the Second Edition has been beefed up?
The discussion of network security has been doubled, the coverage of TCP/IP
and associated protocols (ARP, RARP, ICMP, etc.) has been greatly increased,
and there is a much heavier emphasis on some key applications and how they
work (e.g., email, news, WWW).
What material from the Second Edition is unchanged?
The example protocols used for pedagogical purposes, and the material on
802 LANs and bridges is essentially as it was. The author's congenital
sarcasm has remained intact.
What material has been removed?
All the material on the OSI protocols is gone.
In its place is a long (and hopefully instructive)
description of why OSI failed.
The material on MAP, TOP, and SNA is all gone.
The chapters on the session layer and presentation layer have been removed.
Let's get down to nuts and bolts. How has Chapter 1 (Introduction) changed?
The introductory material on what networks are used for has been brought
up to date.
Both the TCP and OSI models are discussed, and both are critiqued.
The example networks discussed now include Novell NetWare, the Internet,
and some experimental gigabit networks.
Also, SMDS, frame relay, B-ISDN, and ATM are introduced here.
How has Chapter 2 (The Physical Layer) changed?
New material on wireless transmission has been added.
The discussion of the telephone system now focuses on the modern digital
telephone system.
N-ISDN and B-ISDN are discussed.
There is a beefed up section on cellular radio, and a new section on
low-orbit satellite projects, such as Iridium.
The material on terminal handling has been removed.
How has Chapter 3 (The Data Link Layer) changed?
The order of chapters 3 and 4 have been reversed.
Experience teaching from the book has shown the new way to be easier for
students.
This chapter is the only one that is relatively unchanged.
The series of simple protocols given as pedagogical examples was very
popular and effective, and has been basically left intact.
The biggest change here is that all the protocols have been rewritten in C.
Other changes include the removal of the long algebraic determination
of the optimum packet size and the addition of material on SLIP, PPP, and
ATM.
How has Chapter 4 (The MAC Sublayer) changed?
The discussion of ALOHA has been shortened and some of the older
channel access protocols have been removed to make space for wavelength division
multiplexing, wireless LAN protocols, and digital cellular radio.
The old ARPANET packet radio section has been removed, and a new section on
high-speed LANs (fast Ethernet, HIPPI, fibre channel) has been added.
How has Chapter 5 (The Network Layer) changed?
Most of the older routing protocols have been replaced by newer ones, such
as distance vector routing and link state routing.
Multicast routing (RSVP) is also included now.
There are also long sections on the network layer in the Internet (IPv4,
IPv6, and related protocols), and in ATM networks.
How has Chapter 6 (The Transport Layer) changed?
The biggest change here is the addition of a large amount of material on
the transport layer in the Internet (TCP and UDP) and material on the AAL
protocols in ATM networks.
A substantial section on network performance and gigabit networks has been
added.
How has Chapter 7 (The Application Layer) changed?
The material on network security has been doubled in size and placed here,
along with new material on DNS and SNMP.
However, the biggest change is the extended treatment of how email
(including PGP and PEM), USENET
news, the World Wide Web (including HTML, HTTP, and Java), and multimedia
(including video on demand and the MBONE) are implemented. Together, these
topics cover over 100 pages.
Has anything else changed?
Most of the exercises have been changed to reflect the new material.
The author must have been a busy beaver last year, no?
He noticed that too.
Are there any new teaching aids?
Yes, there are now three teaching aids.
In summary, what are the strengths of the Third Edition?
What are the weaknesses of the Third Edition?
It weighs over 1 kilogram
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