Network Connectivity Devices Question And Answer | letsbug

 Network Connectivity Devices

1.  Answer the following questions in short.

1. What are network connectivity devices?

    Answer: 

        Network Connecting devices includes all computers, peripherals, interface cards and other equipments needed to perform data-processing and communications within the network.

        Example: Network Interface Card(NIC), Hub, Switch, Bridge, Router, Gateway.

2. What is active and passive hub?

    Answer: 

        Active hub is a type of hub that takes active participation in data communication within the network/LAN. An active hub is basically a multiport repeater of the class II type, although it is still a physical layer device - it buffers incoming frames and regenerates them, sending the regenerated signal out on all of its ports.

        Passive hubs does not provide any additional features except for working just as an interface between the topology. A passive hub simply receives signals on input port and broadcast it on the output port without even rectifying them.               

3. What are types of bridges in networking?

    Answer: 

        Three types of bridges are used in network:

1. Transparent Bridge
2. Source Route Bridge
3. Spanning Tree Bridge

4. Describe the term transparent bridge.

    Answer: 

• A transparent bridge is a type of Network Bridge. It interconnects several computers in a network by forwarding packets to hosts.
• A transparent bridge is a bridge whose presence and operation in invisible to host on the network.
• A transparent bridge does nothing except block or forward data based on the MAC address. 
• Physically, a transparent bridge looks like a box with two or more holes (ports) where network cables are plugged. The other extreme of each cable is usually connected to the network port of a computer, or to another network device, which is further connected to one or more computers.

5. Which two frame types are used in order to find the route to the destination network segment in Source Route Bridging?

    Answer:

        With source route bridging two frame types are used in order to find the route to the destination network segment:Single-Route(SR) frames and All-Route(AR) frames.

• Single-Route(SR) frames make up most of network traffic and have set destinations, while All-Route(AR) frames are used to find routes.
• Bridge send AR frames by broadcasting on all network branches; each step of the followed route is registered by the bridge performing it.
• Each frame has a maximum hop count, which is determined to be greater than the diameter of the network graph, and is decremented by each bridge. Frames are dropped when this hop count reaches zero, to avoid indefinite looping of AR frames.
• The first AR frame which reaches it destination is considered to have followed the best route, and the route can be used for subsequent SR frames; the other AR frames are discarded. The method of locating a destination network can allow for indirect load balancing among multiple bridges connecting two networks.
• The more a bridge is loaded, the less likely it is to take part in the route finding process for a new destination as it will be slow to forward packets.
• A new AR packet will find a different route over a busy path if one exists. This method is very different from transparent bridge usage, where redundant bridges will be inactivated; however, more overhead is introduced to find routes, and space is wasted to store them in frames.

2.  Define the following terms:

1. Gateways

    Answer: 

        Gateways make communication possible between different architectures and environments. They repackage and convert data going from one environment to another so that each environment can understand the other's environment data.

2. Source routing bridges

    Answer: 

        The source bridge derives its name from the fact that the entire path that the packet is to take through the network is embedded within the packet. Used in Token Ring networks.

3. Router

    Answer: 

        Routers are networking devices which interconnect two different networks. For an example your home router connects your internet connection with a private local network.  

        Router works at the Network Layer of the OSI reference model. This means they can switch and route packets across multiple networks. They do this by exchanging protocol-specific information between separate networks.

4. Hub

    Answer: 

        A hub is a medium used to collect signals from the input line and redistribute them in various available wirings around a topology( Topologies such as: Arcnet, 10base-T, 10base-F, etc. ).

5. Repeater

    Answer: 

        A repeater is primarily a non-intelligent network device that receives a signal on one of its connections and passes that signal on to all of its other connections after regenerating it.

3.  Answer the following questions:

1. What is Router? Explain its components.

    Answer: 

         Routers are networking devices which interconnect two different networks. For an example your home router connects your internet connection with a private local network.  

        Router works at the Network Layer of the OSI reference model. This means they can switch and route packets across multiple networks. They do this by exchanging protocol-specific information between separate networks.

        Router has four components:

1. Input ports: performs the physical and data link layer functions of router. The bits are constructed from the received signal.
2. Output ports: performs the same functions as the input port but in the reverse order. Packet is encapsulated in a frame and physically transmitted on the line in raw bits fashion.
3. Routing processor: performs the function at network layer. The destination address is used to find the address of the next hop and at the same time the output port number from which the packet is sent out.
4. Switching fabric: is used to move the packet from the input queue to output queue. The switching fabric is most difficult process in router. The following switching techniques are used:
1. Crossbar switching:
2. Banyan switching:
3. Batcher-Banyan switching:    

2. Explain the various network connecting devices.

    Answer: 

         Various network connecting devices are:

1. Hub: A hub is a medium used to collect signals from the input line and redistribute them in various available wirings around a topology( Topologies such as: Arcnet, 10base-T, 10base-F, etc. ).
2. Repeaters:  A repeater is primarily a non-intelligent network device that receives a signal on one of its connections and passes that signal on to all of its other connections after regenerating it.
3. Bridges: Like repeater, a bridge can join segments or workgroup LANs. However, a bridge can also divide a network to isolate traffic or problems.
4. Switches: A network switch is a computer networking device that connects network. The term commonly refers to a Network Bridge that processes and routes data at the Data link layer(layer 2) of the OSI model.
5. Routers:  Routers are networking devices which interconnect two different networks. For an example your home router connects your internet connection with a private local network.
6. Gateways: Gateways make communication possible between different architectures and environments. They repackage and convert data going from one environment to another so that each environment can understand the other's environment data.    

3. Describe hub in brief.

    Answer: 

        A hub is a medium used to collect signals from the input line and redistribute them in various available wirings around a topology( Topologies such as: Arcnet, 10base-T, 10base-F, etc. ). 

        Hubs operate at the physical layer of the Open System Interconnection (OSI) model.

Physical Structure:

1.  A hub is a small rectangular box, often constructed mainly of plastic that receives its power from an ordinary wall outlet. A hub joins multiple computers or other network devices together to form a single network segment.
2. On this network segment, all computer can communicate directly with each other. Ethernet hub are by far the most common type, but hubs for other types of network (such as USB) also exits.

Advantages:

• Hubs offer a convenient, affordable way to build a home or small business network.
• It provides a degree of fault tolerance, because each node has its own connection to the hub, and if the connection fails, only that node is affected.

Disadvantages:

• In early computer networks, nodes were connected together in daisy-chain fashion. Once, all the nodes were connected, each end of the cable would be closed with a terminator.
• The  main  problem with this design was that a break anywhere in the cable meant that the network would not function, and one of the major overheads was the time spent in locating the problem.

Types of Hubs:

• Hubs can be either active or passive.
• Small hubs with five or eight connection port are commonly referred to as workgroup hubs. Others can accommodate larger numbers of devices (normally up to 32).
• These are referred to as high-density devices. Because hubs do not perform any processing, they do a little except enable communication between connected devices.