Section 1: Introduction:
This section discusses about the use of computer networks, network hardware, reference model and some very good examples of computer networks viz. Novell Netware, ARPANET etc..
The contents and the vocabulary used in this section is kept as simple as possible so as to make the things clear even to a layman. All the introductory concepts have been explained with the help of real life example. Like the concept of the multi layered architecture has been well explained with the help of an interpreter – Pg:19. After making the concept clear, the author then moves on to the explanation of the two important models i.e ISO-OSI-Reference Model and the TCP/IP Model. Although both of these models have been explained in details, but still as mentioned earlier, there is always biasness towards the OSI Model. This kind of attitude is not justified, under any circumstances.
Section 2: The Physical Layer:
This section is devoted for the bottom most layer of the ISO-OSI-Reference Model. The chapter discusses in details the various types of transmission modes and media’s available. The explanation of Manchester encoding is wonderful. Proper attention has been given to explain the prominent features of various media’s.
Breaking up of the transmission media into two categories i.e. Guided Media & Unguided Media is good and makes the things more interesting. The working of the OFC (optical Fiber Cable) has been properly explained, starting from the concepts of total internal reflection, to the techniques used in it for generating and trapping light signals.
In addition to this the chapter also explains the working of wireless communication with help of radio, microwaves, infrared and light wave transmission.
The working of cellular radio and communication satellites have been explain in very simple terms. Overall this section is very useful and informative even for the beginners.
Section 3: The Data Link Layer:
This section deals with the second layer of the OSI Model i.e. the Data Link Layer. It explains the elementary data link protocol. Although the concepts/ protocols explained in this section are very confusing, but still Tanenbaum has taken well care so as to make the things clear.
The negative part of this section is the use of the C code to explain the working of the data link protocols. These codes make the things worse, as they are hard to understand initially.
Along with the explanation of the data link protocols, this chapter also covers the very important topics of Error correction and Error detection. The techniques used for the error correction and detection viz. CRC, bit stuffing, character stuffing and others have been well explained. But still the author in this case is well behind the explanation given by William Stalling in his book on Computer Networks. Definitely Tanenbaum need to pick up a few tips from the book of Stallings so as to make error correction and detection simpler.
Section 4: The Medium Access Sub layer:
Definitely as things move forward, the topics covered also become more complex and difficult. The fourth section in the Computer Networks is devoted for explaining the MAC sub layer, which is in fact a part of the Data Link Layer (Section : 3). This section incorporates very important topics like the channel allocation problems, multiple aloha protocols, bridges, high speed LAN’s, satellite networks and last but not least the IEEE standards for LAN’s & MAN’s.
Things at this stage start becoming more complex and the reader seems to get lost into a number of protocols and techniques explained. But still Tanenbaum has taken care to arrange the topics carefully in a systematic fashion and in a proper order.
The things which are lagging in this section is definitely the explanation of the latest IEEE sections. The book covers only up to IEEE 802.11 standard, whereas as per the date many more standards have been developed. Today we work on new technologies like the Blue tooth, WiFi and many more which has been designed under the IEEE 802.16 standards for wireless communication. This thing has been properly taken note of and Tanenbaum has explained these standards in the new edition of his book.