Ch. 1 Computer Network Fundamentals
During a recent network redesign meeting, one team member suggested that you implement a device that operates at both the Data Link layer and the Network layer of the OSI model. Which device operates at both of these layers?
A brouter operates at both the Data Link layer (Layer 2) and the Network layer (Layer 3) of the Open Systems Interconnection (OSI) model. A brouter can act as a bridge or a router. When acting as a bridge, a brouter operates at the Data Link layer of the OSI model. When acting as a router, a brouter operates at the Network layer of the OSI model.
Which of these has helped reduce wiring, weight, and cost in industrial applications?
A controller area network (CAN) is used in industrial applications, originally in automotive systems. It replaces bulky wiring systems, reducing weight and cost. A CAN builds a network between controllers, allowing them to share information. A railway application, for example, might be a sensor that detects whether or not a door is closed, and locks the brakes until the sensor indicates the door is closed.
What device operates at Layer 1 of the OSI model?
A hub operates at Layer 1 and moves bits, ignoring addressing.
What WAN topology enables you to minimize WAN expenses by not directly connecting any two remote locations?
A hub-and-spoke topology enables you to minimize costs by not directly connecting any two spoke locations. A ring topology would connect all remote locations to each other. A full mesh would also connect all remote locations, and a partial mesh topology would connect some.
Which wireless topology only requires one access point to be physically connected to the wired network, while still offering maximum flexibility and redundancy?
A mesh topology in wireless networks only requires one access point to be physically connected to the wired network. In traditional wireless networks, each access point must be physically connected to the wired network. With a mesh topology, the other access points are interconnected wirelessly, allowing for flexibility and redundancy.
Which of these would a hospital group use to connect its various neighborhood offices to the main facility when all are located within the same city or region?
A metropolitan area network (MAN) would be used by the hospital to connect its various neighborhood offices to the main facility when all are located within the same city or region. MANs connect several LANS together in an area roughly the size of a city.
What device operates at Layer 3 of the OSI model?
A router operates at Layer 3 and moves packets between networks based on a Layer 3 address.
What device would forward information using the following address as its primary information: 192.168.1.101?
A router operates at Layer 3 and moves packets between networks based on a Layer 3 address. Most commonly, this is an IP address. 192.168.1.101 is an example of such an IP address.
What device would forward traffic based on a MAC address?
A switch operates at Layer 2 and functions based on Layer 2 MAC addresses.
What type of network has a dedicated file server, which provides shared access to files?
Client-server
What topology is seen in WAN networks and was designed to increase the redundancy of the communications?
Dual ring
What WAN topology is typically the most complex and expensive to implement?
Full mesh
What WAN topology uses the formula n(n – 1)/ 2 to calculate the number of links required?
Full mesh
Which of the following topologies offers the highest level of redundancy?
Full-mesh
Your company's WAN connects networks in New York, Atlanta, Dallas, and Boston. Each city is directly connected to every other city. Which physical topology is used for your WAN?
In a mesh topology, every device has a dedicated connection to every other device using a series of point-to-point connections. In the case of a WAN, a mesh topology connects each individual network to each other network in an intra network. This type of topology is very expensive because of its redundant links, but it provides a high level of fault tolerance. Therefore, it is typically seen in a WAN environment where fault tolerance is a major concern.
What type of network allows interconnected devices to share their resources with one another but would have issues regarding scalability?
Peer-to-peer
How many WAN links are required to create a full mesh of connections between five remote sites?
Remember, the formula for the number of connections required for the full-mesh topology is n(n-1)/2, where n is the number of nodes. So, in this case, 5(5-1)/2 is 10.
What topology could result in a lack of all communication capabilities with a single connection break?
Ring
In the modern LAN, what topology is often used with LAN switches and Ethernet connections?
Star topologies, and specifically extended star topologies, are found in modern LANs today. Rings and dual rings are seen often in WAN topologies. A bus topology was seen in the earliest of Ethernet environments.
In the modern LAN, what type of device is typically used at the center of a star topology?
Switch
Which device makes traffic-forwarding decisions based on MAC addresses?
Switches forward traffic based on the destination MAC (hardware) address contained in the data frame. Contrast this to a router, which makes forwarding decisions based on the destination IP address.
Which of the following is an advantage of a peer-to-peer network, as compared with a client/server network?
The P2P network is often celebrated due to its simplicity and low cost. Unfortunately, it is not scalable and can actually cause administrative nightmares when attempting to scale it.
Identify two advantages of a hub-and-spoke WAN topology as compared to a full-mesh WAN topology.
The hub-and-spoke is actually a form of a partial-mesh topology. This topology has the advantage of being less complex, less costly, and overall more scalable than a full-mesh design.
What topology features a central location that connects to each remote connection but does not feature connections between those remote locations directly?
The hub-and-spoke topology features a central location that connects to each remote location. The ring and dual ring, in addition to the full mesh, do not feature the connectivity described here.
What type of wireless topology features the use of access points to facilitate network communications?
The infrastructure type of topology features specialized nodes (access points) that permit communications between other nodes.
Which of the following provides the media (wired or wireless) to facilitate the transfer of data?
The local area network (LAN) consists of many different components. One critical aspect is the media (wired or wireless) that can transmit the data from node to node.
What topology aims to balance redundancy with easier management and cost-effectiveness?
The partial mesh network seeks to add redundancy where needed, but also is easier to manage and more cost-effective than the full mesh. The ring and dual ring topologies are either nonredundant or redundant, but there are no measurable differences in management ease.
A network formed by interconnecting a PC to a digital camera via a USB cable is considered what type of network?
The personal area network (PAN) features fewer nodes than typically found in a LAN. This design also features a small geographic area, such as a car or a single room office.
What topology was used in an early LAN technology that used the passing of a token to transmit?
The ring topology was featured in Token Ring. Star topologies, and specifically extended star topologies, are found in modern LANs today. A bus topology was seen in the earliest of Ethernet environments.
Which of the following physical LAN topologies requires the most cabling?
The star topology is common today in switched LANs. However, it does feature quite a bit of cabling, as the switches require media to each and every node (wired) that needs to communicate. There are also typically trunk connections between the switches for an extended star topology, which requires even more cabling.
What network type would help facilitate communications when large video or audio files need to be housed and transferred through the network?
The storage area network (SAN) assists when large amounts of data must be stored in the network and transferred efficiently from various nodes to other nodes.
Which technology is widely used in home automation, such as smart lights, locks, and thermostats?
Z-Wave is a wireless technology that is widely used in home automation, such as smart lights, locks, and thermostats. It creates a wireless mesh network with a primary controller. Each device communicates with its nearest neighbor, much like routers communicate with each other.
A company has various locations in a city interconnected using Metro Ethernet connections. This is an example of what type of network?
metropolitan area network (MAN)
