Chapter 9 In-Depth TCP/IP Networking

In previous chapters we have learned that TCP/IP is a complex and highly customizable protocol suite. This chapter builds on these basic concepts, examining how TCP/IP based networks are designed and analyzed. It begins by explaining Subnetting. Subnetting separates a network into multiple defined segment or subnets. This might be done to achieve the following.

• Enhance security
• Improve performance
• Simply troubleshooting

 An internet gateway is a combination of software and hardware that enables two different network segments to exchange data. A gateway facilitates communication between two different networks of subnets. A public network is one that any user may access with little or no restrictions, whereas private network is a network whose access is restricted to only authorized clients.

All internet mail services operate on the same principles of mail delivery, storage, and pick-up though they may use different types of software to accomplish these functions. The following protocols achieve these tasks.

• Simple Mail Transfer Protocol (SMTP)
• Multipurpose Internet Mail Extension (MIME)
• Post Office Protocol (POP)
• Internet Message Access Protocol (IMAP)

The chapter covers the following utility programs that help analyze network traffic.

Ipconfig, Ifconfig, Nbtstat, Hostname, Host, Nslookup to name a few.

The text expands it discussion on the various topics mentioned in this Blog. Again the many pictures, diagrams, and charts helped in clarifying the concept.      

Chapter 8 Wireless Networking

The wireless spectrum is a continuum of the electromagnetic waves used for data and voice communication. Some important fundamentals about wireless networking are: antennas are used both for transmission and receiving wireless signals, wireless signals originate from electrical current, and the signal propagates through the air. Each type of wireless service requires a specifically designed antenna for that service. No matter what paths wireless signals take it is inevitable they will run into obstacles. There are many different frequencies which carry these signals. The wireless standards are noted in the chart below.

Some of the wireless pitfalls you want to avoid are:

• SSID mismatch – Wireless client must specify Service set identifier
• Incorrect encryption - Wireless client must be configured to the same type as access point
• Incorrect channel or frequency – Must use correct communication path
• Standard mismatch – Clients must match the correct standard
• Incorrect antenna – Must have correct antenna place in proper location
• Interference – Causes communication errors

With the proliferation of satellite technology and the reduction in cost this has made it possible to transmit consumer voice, video, music and data. Satellites in recent years have become a means of providing data services mobile clients. Most satellites circle the earth 22,300 miles above the equator in a geosynchronous orbit. This technology is well established and is the least expensive.

Once again this chapter provided a lot of good information about wireless networks. It explained the wireless spectrum, characteristics of wireless transmission, wireless LANs, implementing a WLAN, and wireless WANs. There are many diagrams charts and pictures which help in conveying the message of the material.

Chapter 7 – Wide Area Networks

As the title indicates this chapter is all about Wide Area Networks (WAN). In previous chapters we have learned that WAN’s are networks that connect two or more geographically distinct Local Area Networks (LAN). It covers the following WAN topologies:

• Bus- Wan connected to no more than two other sites in a serial fashion.
• Ring – Each site is connected to two other sites so it forms a ring.
• Star – Single site acts as the central connection point for several points.
• Mesh – All sites are connected to each other.
• Tiered – Sites are connected in star or ring formations are interconnected at different levels.

 It explains Public Switched Telephone Networks (PSTN) and how this media connects computers using telephone carrier equipment. The text covers the different types of service used to accomplish this such as ISDN (Integrated Service Digital Network), DSL (Digital Subscriber Line), and T-Carries.

It proceeds to talk about Broadband cable and its use of coaxial cable. It touches on broadband over powerline. It goes into Sonet (Synchronous Optical Network) which was developed by Bell Communications Research in the 80’s. Sonet specifies framing and multiplexing techniques at the physical layer of the OSI model. It follows up with much detail explaining how it works.

The chapter was loaded with diagrams, pictures and charts which helped in understanding the many concepts presented. I found the chapter very informative.

Chapter 6 - Network Hardware, Switching, and Routing

The chapter began with explaining Network Interface Cards (NIC) and the role they plan. In part they enable a workstation, server, printer, connectivity device or other node to receive or transmit data over the network media. The text goes through three types of NIC’s which are:

• Expansion Board NICs – connected internally to the motherboard.
• Peripheral NICs – connected externally to motherboard.
• On-Board NICs – connected directly to motherboard.

The lesson then walks you through installing a NIC and ensuring it’s functionality.

It talks about modular interfaces specifically Gigabit interface converter (GBIC) and Small form-factor pluggable (SFP’s). These types of network interfaces are commonly used in connectivity devices such as switches and routers. Switches are connectivity devices that subdivide a network into smaller logical pieces. Routers are multiport connectivity device that directs data between nodes on a network. Repeaters are the simplest type of connectivity device that regenerates a digital signal. As for a hub it is the most primitive type of repeater. The chapter covers several other topics like VLANS and TRUNKING, Spanning Tree Protocol (STP), and various router protocols.

For me the chapter was very helpful in clarifying NIC’s and their use. The chapter summary at the end was did a great job reviewing the material.