Lesson 7: Understanding Wide Area Networks

Packet switching is the technology that takes data and breaks them into packets and sends them over a network, sometimes using different routes for each packet. This method allows for efficient and reliable transmission of data by dividing it into smaller units and sending them independently. Unlike circuit switching, which establishes a dedicated communication path, packet switching enables multiple packets to be transmitted simultaneously, optimizing network resources and improving overall performance. Connection switching and network switching are not valid terms in this context.

In Europe, the circuit that is similar to the T1 circuit found in the United States is the E1 circuit. The E1 circuit is a digital transmission format that carries voice and data signals over a 2.048 Mbps line. It is commonly used in Europe and other parts of the world, just like the T1 circuit is used in the United States.

Frame Relay replaced X.25. X.25 was a packet-switching network protocol that was widely used in the 1970s and 1980s. However, it had limitations in terms of speed and efficiency. Frame Relay was introduced as a more advanced and efficient packet-switching technology in the 1990s. It offered higher bandwidth, faster data transmission, and better network performance compared to X.25. Therefore, Frame Relay became the successor to X.25 and was widely adopted by telecommunications companies and organizations.

FDDI (Fiber Distributed Data Interface) is a standard for transmitting data over optical fiber cables. It operates at a speed of 100 Mbps, which is the correct answer. FDDI was commonly used in local area networks (LANs) to provide high-speed and reliable data transmission.

X.25 and Frame Relay are examples of packet switching WAN technologies. In packet switching, data is divided into small packets and transmitted over the network. These packets can take different routes to reach their destination, allowing for efficient use of network resources. X.25 and Frame Relay both use packet switching to transmit data across wide area networks. Circuit switching, on the other hand, establishes a dedicated communication path between two parties for the duration of a call, while connection switching and network switching are not recognized types of WAN technologies.

A virtual circuit refers to the entire circuit when multiple circuits are connected to a site. It is a logical connection that is established between two network devices, providing a dedicated communication path for data transmission. Unlike a physical circuit, a virtual circuit does not require a dedicated physical connection and can be established and terminated dynamically as needed. It allows for efficient and reliable communication between devices by ensuring that data packets follow a predetermined path through the network.

RIP (Routing Information Protocol) is the most popular distance-vector routing algorithm used to determine the best routes within a network. It is a simple and widely supported protocol that uses hop count as its metric for determining the best route. RIP exchanges routing information with neighboring routers and updates its routing table accordingly. It is suitable for small to medium-sized networks but may not be as efficient in larger networks due to its slow convergence time and limited scalability.

When a packet traverses a network, each router acts as a "hop" point. A hop refers to the movement of a packet from one router to another. As the packet travels through the network, it hops from one router to the next until it reaches its destination. Therefore, the correct answer is "hop".

A T3 line runs at a speed of 44.7 Mbps. T3 is a high-speed digital transmission line that can carry data at a rate of 44.7 million bits per second. It is commonly used for connecting large networks, such as Internet service providers or universities, and can support multiple high-bandwidth applications simultaneously.

OSPF (Open Shortest Path First) is the most popular link-state routing protocol used within a large organization. This protocol is widely used due to its scalability, fast convergence, and support for large networks. OSPF calculates the shortest path between routers based on link-state information, allowing for efficient routing and optimal network performance. It is commonly used in enterprise networks to ensure reliable and efficient communication between different network devices.

A CSU/DSU, which stands for Channel Service Unit/Data Service Unit, acts as a high-speed modem for a LAN. It is a device that connects a digital circuit from a LAN to a digital circuit from a WAN, allowing for the transmission of data at high speeds. The CSU/DSU converts digital signals from the LAN into a format that can be transmitted over the WAN, and vice versa. It is commonly used in T1 and T3 connections to provide a reliable and efficient connection between a LAN and a wide area network.

DSL, or Digital Subscriber Line, is a technology that uses wires from the telephone company to provide a broadband Internet connection. DSL utilizes existing telephone lines to transmit digital data, allowing users to access the internet while making phone calls simultaneously. Unlike cable internet, which uses coaxial cables, DSL uses copper wires, making it a popular choice in areas where cable internet is not available. DSL offers high-speed internet connections and is widely used in residential and small business settings.

The primary disadvantage of X.25 is slow speeds. X.25 is a packet-switching network protocol that was commonly used in the past for transmitting data over long distances. However, it operates at relatively slow speeds compared to modern networking technologies. This limitation can lead to delays and reduced efficiency when transferring large amounts of data.

X.25 uses PAD (Packet Assembler/Disassembler) as its DTE (Data Terminal Equipment) device. PAD is responsible for converting data from the DTE device into packets that can be transmitted over the X.25 network, and vice versa. It acts as an intermediary between the DTE device and the network, handling the encapsulation and decapsulation of data packets. PADs were commonly used in the past for connecting devices such as terminals and computers to X.25 networks.

FDDI (Fiber Distributed Data Interface) uses a ring topology. In this topology, all the devices are connected in a circular manner, forming a closed loop. Each device in the network is connected to its neighboring devices, and data travels in one direction around the ring. This topology provides fault tolerance, as if one device or link fails, the data can still flow in the opposite direction. FDDI is commonly used in high-speed local area networks (LANs) that require high reliability and bandwidth.

An ISDN PRI (Primary Rate Interface) supports 23 B channels. B channels are used for carrying voice or data traffic in ISDN communication. In an ISDN PRI, there are 30 channels in total, out of which 23 are B channels and are used for data or voice transmission, while the remaining 7 channels are used for signaling and control purposes. Therefore, the correct answer is 23.

The demarc, short for demarcation point, is the point in the network where the responsibility of the administrator ends and the telecommunications provider's responsibility begins. It is the physical location where the network service provider's equipment connects to the customer's equipment. At this point, the provider is responsible for the network's maintenance, while the administrator is responsible for managing and maintaining their own equipment and network within their premises.

A static route is a route that must be manually defined on each router. Unlike dynamic routes that are automatically learned and updated by routing protocols, static routes require manual configuration on each individual router. This means that network administrators need to manually specify the destination network and the next hop router for the static route. Static routes are typically used in small networks or for specific network configurations where dynamic routing protocols are not necessary or feasible.

Routing is the process used to send packets from one network to another network. It involves determining the best path for the packets to travel through a network, based on factors such as network congestion, distance, and cost. Routing protocols are used to exchange information between routers and determine the most efficient routes for packet transmission. By analyzing network topologies and making decisions based on routing tables, routers can successfully forward packets to their intended destinations across different networks.

A T1 runs at a speed of 1.544.

A CIR (Committed Information Rate) is the guaranteed certain amount of information provided by a circuit or line. It refers to the minimum amount of bandwidth that is allocated to a specific connection or service, ensuring that a certain level of data transmission is always available. This ensures that the connection or service will always have a minimum level of performance, even during periods of high network traffic or congestion.

A static route does not use a clocking circuit to control the timing of communications between two WAN devices such as routers. Static routes are manually configured routes that specify the next hop for network traffic. They do not involve any timing control or clocking circuit. Therefore, the given answer is incorrect and does not provide a valid explanation.

A DS0 circuit is a digital transmission line that operates at a speed of 64 Kbps. This means that it can transmit data at a rate of 64 kilobits per second. This speed is commonly used for voice communications and basic data transfer.