Best-fit Topology for a Wide Area Network
Determine best-fit Topology for a Wide Area Network
- List typical network components for each of the following
- Small LAN
- End hosts (clients and servers)
- Large LAN
- End hosts
- Access points
- Peripheral devices
- Medium (Cables or Wireless)
- Layer 2 Switches
- Multilayer switches
- End hosts
- Access point
- TCP/IP protocol suite
- VPN server
- VPN client
- VPN tunneling protocols
- Authentication protocols
- Multilayer Switches
- End hosts
- Access points
- Peripheral devices
- Medium (Cables or Wireless)
- End hosts
- Wireless Access points
- Peripheral devices
- Explain the difference between a router and a modem. Explain the function of a modem in a WAN
A router is an internetworking device used to connect different networks to form a WAN. It mainly operates in layer 3 (Network Layer) of the OSI reference model when routing network traffic. It also operates in the Layer 2 protocol through its ports during internal communication between devices such as ARP communication. When a router receives a packet, it routes it to the destination using the source and destination information in the packet header and its routing table. A router usually has fewer ports.
On the other hand, a modem is a networking device that provides Internet access via your internet service provider (ISP) to the network devices in a LAN or WAN. As the name suggests, it performs modulation and demodulation of signals in between the networking devices such as PCs or routers and the ISP network. It operates on the data-link layer of the ISO reference model. Unlike routers, a modem does not have inbuilt intelligence. When a modem is connected to a WAN through a router or directly to the end device, it demodulates analog signals from the telephone line or fiber connection so that they can be understood by the network devices in the LAN. On the other hand, a modem modulates data received from the devices in form of digital signals to analog signals in the telephone line so it can easily be understood.
- Describe three types of modems
There are three main types of modems. They include cable and Integrated Services Digital Network (ISDN), digital subscriber line (DSL), and dial-up. A cable modem uses coaxial cables. This type of modem provides higher bandwidth for internet connection with the local network. DSL and dial-up modems use telephone lines. The adoption of fiber optic technology by ISPs and organizations has eliminated the need of using a modem.
- Explain the purpose of IP addresses as part of a WAN
IP addresses are logical identifiers of devices connected to the network to allow communication. They are used to identify hosts and/or network interfaces as well as the logical location (network) to which the device belongs to. IPv4 is a 32-bit address that is divided into 4 octets written in decimal. The growth of the internet has led to the rise of IPv6, a 128-bit address written in hexadecimal. Some portions of the address are used to identify the network while the remaining portions identify hosts. A packet sent over a WAN is encapsulated with a packet header containing source and destination to help route the traffic to its destination using the best route.
- Explain how a packet switching works within a WAN
In packet switching, data is encapsulated into chunks called packets containing the IP header. Before adding the layer 3 header, an ethernet header is first added to the data forming a segment. The IP header contains the source and destination addresses among other header information such as time to live (TTL) and version. The packets are required to have this information since they do not always use the same route to get to their intended destination. Packets may take a different route if a particular route is not accessible due to various reasons. The IP header also contains the sequence of the packets to help in rearranging the packet once they reach the destination.
- Explain how routers work
When a router receives a packet, it checks whether a valid route exists in its routing table by comparing it with the destination IP address contained in the header. If a path does not exist, the packet is dropped. If a path exists, it decapsulates the PDU, adds its layer 2 MAC address and the destination MAC address of the next-hop, and then forwards the packet to the next router. If the destination MAC address of the next router does not exist, the router will send ARP messages to get the MAC address of the next router. Once it gets the MAC address, it encapsulates the data and forwards the packet. This process repeats itself until the packet reaches its destination. The source and destination IP address information in the layer 3 header does not change when the packet passes through the routers. When receiver then decapsulates the packet by removing the headers to understand the message.
- Explain routed protocols and give three examples
A routed protocol is forwarded by a router to another or other hosts. Assist in the delivery of host-based data traffic. Internet Protocol (IP), Hypertext Transfer Protocol (HTTP), and Secure Shell protocol (SSH) are examples of routed protocols.
- Explain routing protocols and give three examples
Routing protocols specifies how routers communicate. They enable users to forward information that helps them to select routes between any two hosts in a network. Routing protocols help routers send and receive packets containing routing information to and from other routers and devices. Examples of routing protocols include Routing Information Protocol (RIP), Open Shortest Path First (OSPF), and Enhanced Interior Gateway Routing Protocol (EIGRP).
- Explain the function of a TCP
TCP is a connection-oriented protocol used for establishing, managing, and terminating connections to ensures the secure and reliable transmission of data traffic in a network. It guarantees the integrity of data sent over the network, regardless of the amount. It provides flow and congestion control mechanisms.
- Explain the concept of double data rate (DDR)
This technology allows the transfer of data on both the rising edge and falling edge of a single clock cycle. This increases the memory bandwidth by transferring data twice per clock cycle. The registration of addresses and control signals happens at every positive edge of the cycle.
- Explain how microwave and satellite communication can be used in networking
Microwaves can be used for networking purposes through sending of microwave wireless signals using antennas. It can be used to transfer large blocks of data. Satellite communication relays and amplifies transmission through satellite dishes, without using cables and telephone lines.
- Explain the advantages and disadvantages of WAN to assist a company in making that decision about constraints and costs associated with each
It covers a wide geographical area thus suitable for business with branch offices or operations in different regions. WAN also ensures centralization of data which allows sharing the network resources without additional facility needed. Wide Area Networks also ensures collaboration and cohesiveness in operation. WAN also has a higher bandwidth due to its large coverage.
The setup cost for WAN is high. This is because it covers a wider geographical region and requires purchasing more network devices. WAN networks are more vulnerable to cyberattacks due to their exposure to the internet. Therefore, the organization must deploy firewalls, antimalware, and security teams to mitigate the threat. This is increasing the expenses for the company to maintain the network. Due to the large geographical area covered by WAN, troubleshooting and maintenance are also expensive.
- Explain the difference between Synchronous Transmission and Asynchronous Transmission. Give examples of each
In asynchronous transmission, the sender and the receiver use a common clock. This mode is preferred for communication involving large chunks of data at higher bandwidth. For example, when streaming a video from a website. On the other hand, asynchronous transmission involves communication where the transmitter and the receiver have two independent clocks that are used on either side. Asynchronous mode is applied only when the character generation rate is unknown or the bandwidth is too low. For example, when typing using a keyboard, the intervals between successive keystrokes are random and unpredictable.
- Describe two constraints associated with establishing a WAN, including an explanation of how the constraints affect network design
The first constraint is the budget constraint. Resources required to create a WAN require the company a lot of finances due to the many and expensive components required for the network. This affects the design by limiting the hardware and software to be deployed. The second constraint its complexity, thus, taking too long to design and implement.
- Explain the key features of digital and analog networks and give the key differences between each.
Digital network system uses discrete binary signals to transmit data. It uses the “On/Off” signals, where “On” represents 1 and “Off” represents 0. On the other hand, analog network systems use continuous electronic pulses with fluctuating magnitude to send data.
Uses discrete signals
Uses continuous varying wave
The signals from a square-shaped wave
Uses sine wave
Digital network communication is easy and can be made noise-proof with no loss at all
Analog communications are easily affected by noise.
Require more bandwidth
Require less bandwidth
Require more energy
Consumes less energy
- Explain the process a network manager must follow to ensure growth projections are accurately forecasted and capacity is effectively planned.
The first step is the documentation of the current network infrastructure including the equipment and technology used, performance metric, and then assessing the potential need for growth. The planning is dependent on the current capacity, utilization, and demand for upgrading the network. After identification of the potential and demand, the network manager can proceed to capacity refinement.
- Explain at least two considerations for a business when deciding on whether to opt for low or high-speed links
A business should consider the cost and purpose of the network when deciding on low and high bandwidth for the network. If the data shared does not require high bandwidth (such as web services), then the business should opt for low-speed links if getting high-speed is expensive. However, for services that require high bandwidth such as video and VoIP, the business should consider opting for high-speed lings
- Explain the difference between LAN and WAN protocols.
LAN protocols are differentiated by their capability to effectively enhance communication over shorter distances through mediums, such as copper cabling or wireless. Examples of some common LAN protocols include ethernet and token ring.
WAN protocols are capable to effectively allow network communication over longer distances, such as hundreds of miles. They ensure the transfer of network traffic between LANs. Example of WAN protocols include Point-to-Point (P2P) protocol and Frame-Relay
- Explain two considerations for a business when determining redundancy paths for a WAN
There are two main factors to consider when determining redundancy paths for a WAN. They include availability and cost of resources and the cost of network failure. If the business has enough resources to deploy the devices, it should ensure more redundant paths to reduce chances of network failure. Additionally, if the potential loses of the networking services threatens the business continuity or exceeds implementation and maintenance costs, the business must, therefore, must have redundant links to prevent downtimes.
- Explain the importance of response time and reliability for a WAN
Reliability ensures that critical network resources are always available to the user. This ensures business continuity. Response time allows users to regain network access, thus, increasing productivity.
- Explain two methods that can be used to ensure the security of a WAN
A firewall can be used to elevate the security of a WAN. A firewall filters traffic and blocks certain traffic based on a defined set of security rules. The second method is encryption. Encrypting data will ensure that a third party (middleman) can not listen or eavesdrop on the communication between two nodes in the network. This safeguards the integrity of data.
- Explain why it is important to assess traffic load and flow patterns when establishing a WAN
Assessing traffic load and flow patterns will assist in network segmentation. The networking practitioner will be able to divide the network into multiple segments to have better control of network traffic flow. Allowing certain traffic and blocking others will help improve performance, isolate networking problems, and also increase security.
- Explain why it is important to assess users and expected applications when establishing a WAN
The determined traffic characteristics should match the users’ needs and the requirements of the expected applications. Designing a WAN based on this factor will ensure an optimized network and proper allocation of network resources such as bandwidth and preferred topology. For example, a hospital will require a different WAN set-up as compared to a music band business since users’ needs, type of network traffic, and applications used are different.