Chapter 15 Network Management

Network management in simple terms is the assessing, monitoring and maintenance of all aspects of the network. A key element in being successfully is clear concise documentation. Some of the ways this is accomplished is through system logs, event logs, and through syslog.

Asset management is another important component in managing networks through identifying and tracking software and hardware. By doing so this simplifies maintaining and upgrading the system because you know what the system includes.

The chapter talks about many different types of upgrades. The following are just a few:

• Adding or Upgrading Equipment
• Cable upgrades
• Backbone upgrades 

All could be very expensive if not designed and implemented properly.

This chapter was an overview of many other concepts presented in the book. It stressed the importance of continual review and adjustment to the network. It explained the best ways to implement those changes.   

Chapter 14 Ensuring Integrity and Availability

This chapter is all about safeguarding your data and protecting your network. It discusses backup and recovery practices and as well as disaster recovery and contingency plans. It begins with two important concepts Integrity and availability. That is to say integrity refers to the soundness of a network’s programs, data, services, devices, and connections. Availability refers to how consistent and reliably a file or system can be accessed by authorized personnel. 

The text goes into discourse about Malware and the various types and characteristics. It follows-up with malware protection, anti-malware software and polices. If malware is unchecked it will wreak havoc on the system.

Safeguarding against malware is important; however another key component in maintaining the availability and integrity of data is fault tolerance. Fault tolerance is the capacity for a system to continue performing despite an unexpected software or hardware failure. Examples of potential areas that need to be monitored are Environment, Power, and Network design. Maintaining these areas is key in keeping fault tolerance to a minimum.

It is also important to have a backup strategy and storage plan. It could entail optical media, tape backups, external disk backup or network backups. This would be a good time to lay out a disaster recovery plan along with any contingencies. 

Chapter 13 Troubleshooting Network Problems

The chapter provides a logical and methodical way for troubleshooting network problems. This serves as a basic road map for identifying and resolving network issues. The process begins with identifying the problem and its symptoms. It is then important to determine the problems scope. Which is to say how many users are affected, a work group, a department, or the entire company? This data helps in determining the magnitude of the issue. The following bullet points provide a means to capture this information.  

•  Gather information
•  Identify symptoms
•  Question users
•  Determine if anything has changed

 After you have identified the scope of the problem it is then time to establish a theory of probable cause. An excellent way to learn more about the problem is to recreate the symptoms. One needs to be very careful in doing this because this could cause havoc for the system.  You must ask the obvious questions at this stage to help determine cause.   

Next you should test the theory to determine cause. It may be something as simple as a plug unplugged or a cable disconnected. The following bullet points provide a path.

•  If theory confirmed, determine next steps
•  If theory not confirmed, establish new theory or escalate

 At this juncture after you have analyzed the network and have identified the problem it’s time to establish action plan. In the action plan it should take into consideration what impact it will have on the users and network. After development you would implement the solution or escalate for further development. As part of the process the next step would be verify full functionality and implement preventative measures if applicable. And finally document findings, actions, outcomes.

The last part of the chapter spends time covering troubleshooting tools. It looks at tone generators and tone locator's, multimeters, cable continuity testers, cable performance testers, voltage event recorders. These are only a few.

The chapter had a lot of pictures, diagrams, and flow charts. It was very helpful in understanding the methodology of troubleshooting. 

Chapter 12 Voice and Video IP

This chapter is all about the variety of methods in which various signals travel for communication purposes. It begins with convergence, the use of multiply terms to refer to the same or similar technologies in common. For instant IP Telephony the use of any network private or public to carry voice signals using TCP/IP protocol. This technology is commonly known as VOIP. (Voice over IP) There are many different clients and network designs with VOIP. One of the benefits of using IP Telephony is it mobility. Analog VOIP needs to connect to an ATA (analog telephone adapter) which digitizes the data in order for transmitting purposes. It is much easier with Digital VOIP it typically connects to a PBX.

Videoconferencing and streaming video opens another avenue of communication. It allows multiply participates to communicate while viewing each other. This type of communicating depends upon the exchange of information between the components of a network system to establish connection.

The text provides some really good insight as to how all this different communication processes work. This synopsis only scratches the surface; the chapter goes into much more detail and covers many more topics.

Chapter 11 - Network Assessment

The threat of an outsider accessing an organization’s network via the internet and then stealing or destroying data is a real possibility today. Before spending any money or time on network security you should examine the network’s security risks. An organization should conduct a posture assessment which is a thorough examination of each aspect of the network to determine how it might be compromised. A security audit asses the security of your network.

Security risks come from all types of vulnerability weaknesses. When these weaknesses are taken advantage of it is known as exploiting. The following areas are of real concern:

• Risks Associated with People
• Risks Associated with Transmission and Hardware
• Risks Associated with Protocols and Software
• Risks Associated with Internet Access

 In an effort to help mitigate these risks an effective security policy goes a long way. It begins with identifying your security goals, risks, levels of authority, designated security coordinator, and team members’ responsibilities for each team member as well as responsibilities for each employee. It encompasses the following areas:

•  Security Policy Goals
• Security Policy Content
• Response Policy

 The chapter goes into myriad of topics discussing the various types of Physical Security, Security in Network Design, Network Operating System Security, Authentication Protocols, and Wireless Network Security. Each one these areas are delved into with much detail.

I found this chapter to be very helpful in reviewing some previous learned topics. It was presented in an organized and informative manner

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.      

Chapter 5 Topologies and Ethernet Standards

The chapter begins with explaining Logical and Simply Physical Topologies. Physical topology refers to the physical layout of the media, nodes, and devices on the network. The following are physical topologies:

• Bus topology – consists of a single cable that connects all the nodes on the network.
• Ring topology – each node is connected to the two nearest nodes so that the entire network forms a circle.
• Star topology – every node is connected through a central device.

Hybrid Topologies consist of more complex combinations of topologies. Two kinds of hybrid topologies are:

• Star-Wired Ring - This uses the physical layout of a star in conjunction with the ring logical topology.
• Star-Wired Bus – This topology combines the star and bus formations.

Logical Topologies – refers to the way in which data are transmitted between nodes, rather than the physical layout of the paths that data take.

Backbone Networks – is the part of the network to which segments and significant shared devices connect.

• Serial Backbone – is the simplest kind of backbone. It consists of two or more devices connected to each other by a single medium in a daisy chain fashion.
• Distributed Backbone – consists of several intermediate connectivity devices connected to one or more central connectivity devices.
• Collapsed Backbone – uses a router or switch as the single central connection point for multiple subnetworks.
• Parallel Backbone – is the most robust type of network backbone. The key point is that a parallel backbone is redundant.

The text goes into great detail about the Ethernet and how it is a flexible technology and that all Ethernet networks have a common thread which is their access method. This is known as CSMA/CD. The following diagram covers the process.

                                                                 CSMA/CD Process

It covers the Ethernet standards for copper cable and fiber optic cable. The following chart is a summary of common Ethernet standards.

I found the visual depictions to be very helpful in understanding the various concepts in this chapter. The chapter was presented in a logical and organized manner which helped in grasping the material.   

Chapter 10 - Virtual Networks and Remote Access

In this chapter we learned about Virtualization. Very simply it is the emulation of a computer on a physical system. It also could be of an operating system or an application. Virtualization offers many advantages such as:

• Efficient use of resources
• Cost and energy savings
• Fault and threat isolation
• Simple backups, recovery, and replication

However some disadvantages are:

• Compromised performance
• Increased complexity
• Increased licensing costs
• Single point of failure

 Virtual networks can consist of virtual machines on a physical server. More common are networks that combine physical and virtual elements. Virtual network components include a virtual adapter or vNIC which is required to connect to a network. Virtual bridges or ports on a switch connect to vNICs with a network, whether virtual or physical. A virtual switch is a logically defined device that operates at the data link level to pass frames between nodes. Network connection types include bridged (physical network using the host machine NIC), NAT (relies on the host machine to act as NAT device), and host-only (exchange data with each other and host only).

The text covers remote access and virtual computing through the following methods:

• Dial-up Networking
• Remote access servers
• Remote access protocols
• Remote virtual computing

 The chapter speaks to Virtual Private Networks (VPNs) which are wide area networks that are logically defined over public transmission systems. It concludes with cloud computing (see below) which refers to the flexible provision of data storage, applications, or services to many clients over a network.

I found the material to be very informative but yet concise. There were a lot of good diagrams and illustrations to help make key points.      

Chapter 4 Introduction to TCP/IP Protocols

This chapter is all about “Protocol”. As we have learned Protocol is the rule that governs computers and the exchange of data on the network. The protocol suite which is virtually on all networks today is Transmission Control Protocol/Internet Protocol. (TCP/IP) It is not just one protocol rather a suite of specialized protocols, including TCP, IP, UDP, ARP, and many others called subprotocols. TCP/IP has become the standard based on the following advantages:

• It is open rather than proprietary – not owned by any company.
• It is flexibly – can run on virtually any platform.
• It is routable – can be interpreted by routers.

The following diagram depicts the TCP/IP model. It is essentially four layers that correspond to seven of the OSI model.

The OSI model is considered more theoretical whereas the TCP/IP is considered more practical. Understanding what functions belong to each layer of the model will be beneficial when analyzing problems.

The following is a list of subprotocols of the TCP/IP suite.  These core TCP/IP protocols operate in the transport or network layers of the OSI model and provide basic services to protocols in other layers.

• TCP - Transmission Control Protocol provides reliable data delivery services.
• UDP – User Datagram Protocol is a connectionless transport service.
• IP – Internet Protocol provides how and where data should be delivered.
• IGMP – Internet Group Management Protocol manages multicasting on networks running IPv4.
• ARP – Address Resolution Protocol creates a database that maps the MAC address to the IP address.
• ICMP – Internet Control Message Protocol reports on success or failure of data delivery.

The following list application layer protocols translate user requests into a format the network can read.

• Telnet- is a terminal emulation protocol used to log on to remote hosts using TCP/IP suite.
• FTP – File transfer Protocol is used to send and receive files via TCP/IP using ports 20 and 21.
• TFTP - Trivial file transfer protocol that enables file transfers between computers but is simpler.
• NTP – Network time protocol is used to synchronize clocks of computers on a network.
• Ping – Packet Internet Groper is a utility that can verify that TCP/IP is installed.

 The most common way to express an IP addresses is the Dotted decimal notation. This refers to the shorthand convention used to represent IP addresses and makes it easy for people to read. An example of a dotted decimal IP address is 121.44.12.18. In addition to an IP address that is running IPv4, a subnet mask is assigned. A subnet mask is a special 32 bit number that when combined with the device’s IP address informs the rest of network about the segment or network to which the device is attached.

The chapter covers the assigning of IP address and DHCP (Dynamic Host Configuration Protocol) which is an automated means of assigning a unique IP address to devices on the network. It explains DHCP leasing and terminating lease process. It also, briefly talks about “private and link-local addresses” which is a means to extend the number of available addresses along with some other features.

The text also talks about Host names and DNS (Domain Name System) and sockets and ports.

There was a great deal of material in this chapter which helped provide a good understanding of Protocols and the OSI model and the TCP/IP model. This will be a good reference chapter for future use.  

Chapter 3 – Transmission Basics and Networking Media

This chapter gets into the nuts and bolts of transmitting analog and digital signals over various medium. It begins by explaining the four fundamental properties of an analog signal. They are amplitude, frequency, wavelength, and phase.

• Amplitude – is a measure of its strength at any given point in time.
• Frequency – is the number of times that wave’s amplitude cycles from its starting point, it’s expressed in cycles per second or hertz (hz).
• Wavelength – is the distance between corresponding points on a wave’s cycle.
• Phase – refers to the progress overtime in relation to a fixed point.

 Digital signals are comprised of pulses which are positive voltages or zero voltages. This equates to a zero for no voltage present or one if voltage is present. These ones and zeroes are characteristics of the binary system. Every pulse in the digital signal is called a bit. Because digital transmission involves sending and receiving only a pattern of 1s and 0s it makes it more reliable then analogy transmission.

The text then goes into the sending of these signals and data modulation and the direction of signals. If the signal is traveling in one direction it is considered simplex. In half duplex transmission, signals may travel in both directions over a medium but in only one direction at time. Full-duplex can travel in both directions at one time. It then leads into throughput which essentially is the measure of how much data is transmitted in a given period of time, whereas bandwidth is the measure of difference between the highest and lowest frequencies.

Some common transmissions flaws are noise and attenuation. Both have negative impact on the signal strength. These flaws can be caused by a number of issues such as type of connectors used, type of wire used, and even installation methods. The chapter talks about the different types of cables in great detail along with splicing techniques.

I found the chapter to have a lot of good information. The material was understandable and presented systematically. It was a good foundation chapter.      

Chapter 2 - Networking Standards and the OSI Model

The text begins with network standards organizations and the necessity of maintaining minimum industry standards. The chapter gives a brief description of each following along with the role they play:

• ANSI – American National Standards Institute
• EIA – Electronic Industries Alliance
• IEEE – Institute of Electrical and Electronics Engineers
• ISO – International Organization for Standardization
• ITU – International Telecommunications Union
• ISOC – Internet Society

The OSI model began in the early 1980’s and set universal specifications that made it possible for computer platforms across the world to communicate. The OSI (Open Systems Interconnection) model represents seven layers in network communications. See chart below.

In this model the layers communicate with the same layer from one computer to another. A way to help remember these different layers is to create a sentence using words that begin with the first letter of each layer. For example “Programmers Dare Not Throw Salty Pretzels Away”.

It is important to understand that data issued from a software application are not in the same form as the data that your NIC (network interface card) sends to the network. At each layer of the OSI model, some information is added to the original data. The data requests that transfer between layers is done in the form of protocol data units (PDU). Finally, your request in the form of many frames hits the NIC at the physical layer. The physical layer does not interpret the frames or information it simply transmits them over the broadband.

I found this chapter to have a wealth of information as well as many diagrams and charts. I thought it had a systematic and logical approach in its presentation. It was good foundation material.      

Chapter 1 – Introduction to Networking

This chapter was a good starting point it discussed and provided suggestions for finding a job in networking field. A few ideas discussed were to search the Web, visit a career center, and network with like-minded professionals. These were only a few of the many suggestions covered. It went on to talk about pursuing a certification and the benefits from doing so, such as better salary, greater opportunities, access to better support, and professional respect. 

The lesson began with covering networks. It touched on how networks are used and the various services i.e. file and print, access, communications, internet, and management. Each one plays a different role in “network services”. The two fundamental network models are client/server and peer to peer. The following are the advantages and disadvantages of a peer to peer network.

•  Simple to configure.
•  Often less expensive to start up and maintain.

Disadvantage:

• Not very flexible.
• Not necessarily secure
• Not particle for connecting more than a handful of computers.

The other type of network is the client/server which has a central computer known as a server, to facilitate communications and resource sharing between other computers on the network. Some of the common elements of a client/server network are:

• Workstation
• Server
• Client
• Nic (network interface card
• Node
• Host
• Nos (network operating system)
• Packet
• Address
• Backbone
• Topology

The book explains these components. It goes to review how networks are classified by size. Very simply they are LAN (local area network), MAN (metropolitan area network), and Wan (wide area network). 

I found this chapter to be a good foundation in understanding network principles. It provided many diagrams with good descriptions.