aggregation
■ Routing metrics
■ Hop counts
■ MTU, bandwidth
■ Costs
■ Latency
■ Administrative distance
■ SPB
✓ 1.10 Identify the basic elements of unified communication technologies
■ VoIP
■ Video
■ Real time services
■ Presence
■ Multicast vs. unicast
■ QoS
■ DSCP
■ COS
■ Devices
■ UC servers
■ UC devices
■ UC gateways
✓ 1.11 Compare and contrast technologies that support cloud and virtualization
■ Virtualization
■ Virtual switches
■ Virtual routers
■ Virtual firewall
■ Virtual vs. physical NICs
■ Software defined networking
■ Storage area network
■ ISCSI
■ Jumbo frame
■ Fibre channel
■ Network attached storage
■ Cloud concepts
■ Public IaaS, SaaS, PaaS
■ Private IaaS, SaaS, PaaS
■ Hybrid IaaS, SaaS, PaaS
■ Community IaaS, SaaS, PaaS
✓ 1.12 Given a set of requirements, implement a basic network
■ List of requirements
■ Device types/requirements
■ Environment limitations
■ Equipment limitations
■ Compatibility requirements
■ Wired/wireless considerations
■ Security considerations
A few years ago, I wrote, “Computer communication in today’s world is amazing, isn’t it? We seem to be able to connect to each other from wherever we happen to be at that time. Networks seem to ‘stitch’ themselves together almost magically with no effort on anybody’s part! At least, that’s what ‘seems’ to happen.” Well, at that time, I had no idea how much would change about networking in just the next few years!
One of the main aspects of networking that changed is its architecture. The word architecture is defined in Webster’s dictionary as “the style, design, or framework of a structure.” This definition was first applied to buildings, but it most certainly applies today to our networking structure as well. In fact, the style, design, and construction of your network will be determined by your goals and will define what you can accomplish with your network.
In this first chapter, I will discuss the basic building blocks of your network architecture, such as routers, switches, firewalls, and so on. Then I will compare and contrast various networking services from which you have to choose, such as VPNs, web services, unified voice services, and many others. I will also discuss the installation and configuration of essential network services such as DHCP, DNS, and NAT. In addition, I will cover network technologies that are specifically for wide area networks, such as SONET, Satellite, ADSL, and many more. I will also identify the various connectors that you can use to stitch your network together, such as RJ-45s, UTP couplers, F-connectors, and many others. I will then discuss the various network topologies or shapes that you can create using your building blocks and connectors.
Once you understand the building blocks, you will then be able to create a network. However, in order to make that network function, you will also need to understand the addressing protocols that allow computers to communicate with each other through the network. Therefore, I will also cover concepts of common addressing schemas such as IPv4 and IPv6. In addition, I will explain how to use routing protocols so the network components can function together well and deliver network traffic through your network architecture. Of course, we can’t leave out the newest and most sophisticated technologies, so I will also cover unified communications systems, cloud and virtualization concepts, and storage area network concepts.
Finally, based on a defined list of requirements, limitations, and considerations, we will build a network together. Well, at least on paper. Are you ready to get started?
1.1 Explain the Functions and Applications of Various Network Devices
The building blocks of your network architecture consist of various devices that perform a specific function or group of functions for your network. It’s important that you understand the purpose of each device so that you can place it in the right position in your network architecture. In this section, I will cover the function and correct application of each of the most common network devices.
Router
Routers are the devices that connect the Internet and make the World Wide Web possible. They also divide and then rejoin your network. They use a higher level of intelligence than that of switches. Routers use logical addresses and work at Layer 3 (Network) of the OSI model (which I will discuss further in Chapter 5), and they forward traffic from one network (or subnet) to another. Routers first determine whether the traffic belongs on their network; then they deliver it to the appropriate network hosts while forwarding the traffic that does not belong on their network to another router. Routers determine where to forward traffic by consulting a routing table. An administrator can configure the routing table manually, or the router can learn it by using routing protocols. Figure 1.1 shows a common router.
FIGURE 1.1 A router
Switch
A switch is a network device that optimizes traffic flow on your network. A switch works at Layer 2 (Data-Link); it learns the physical address (MAC address) of all the devices that are connected to it and then uses the MAC address to control traffic flow. Some switches, called multilayer switches, also work at Layer 3, but here I am focusing on
