Router Support

If you are a Router Support person looking for your next job, then checkout these frequently asked questions in Router Support to prepare for the next job.

Q.1 What do you understand about Virtual LAN?
A VLAN refers to a switched network that is logically divided by functions, project teams, or applications without regard to the physical location of users. For example, several end stations might be classed as a department like engineering or accounting. When the end stations are physically located close to one another, you can class them into a LAN segment. However, if any of the end stations are in different buildings, you can then classify them into a VLAN. Further, you can also allocate every switch port to a VLAN.
Q.2 Define Attenuation.
This refers to the progressive weakening of a signal as it moves over a cable or other medium. The longer the distance a signal travels, the weaker the signal gets, until it becomes unreadable by the receiving system
Q.3 Describe some of the advantages of the OSI Model.
  • Firstly, it specifies the process for connecting two layers, promoting compatibility between vendors.
  • Secondly, it divides complex functions into simpler components.
  • Thirdly, it provides access to vendors for classifying their design efforts to fit a modular design, which eases implementations and simplifies troubleshooting.
Q.4 Define Hub and Switch.
A Hub refers to a networking device that allows you to connect multiple PCs to a single network. Whereas a Switch connects various devices together on a single computer network. A Hub works on the physical layer, and a switch works on the data link layer.
Q.5 What do you understand about UDP?
UDP stands for User Datagram Protocol that is a communications protocol used for establishing low-latency and loss-tolerating connections between applications on the internet. This speeds up transmissions by allowing the transfer of data before an agreement is provided by the receiving party.
Q.6 Define subnet mask.
A subnetwork or subnet refers to a logical subdivision of an IP network. The practice of separating a network into two or more networks is called subnetting. Computers that belong to the same subnet are addressed with an identical most significant bit-group in their IP addresses. Further, the calculation of a subnet mask can be beneficial while designing a network.
Q.7 What do you understand about IDS?
An IDS is an Intrusion Detection System containing two basic variations: Host Intrusion Detection Systems and Network Intrusion Detection Systems. In which, a HIDS runs as a background utility in the same way as an antivirus program for instance. And, a Network Intrusion Detection System sniffs packets as they go over the network looking for things that aren't quite ordinary. Further, both systems have two basic variants- signature-based and anomaly-based.
Q.8 Define Telnet.
Telnet refers to a small and versatile utility that allows for connections on nearly any port. This gives the admin access to connect to remote devices and administer them via a command prompt. In many cases, this has been swapped by SSH, as telnet transmits its data in cleartext (like FTP).
Q.9 Explain the term shadow copies.
Shadow copies refer to the versioning system in place on Windows operating systems. This provides users access to go back to a previously available version of a file without the requirement for restoring the file from a standard backup. However, the defined features of shadow copies differ from version to version of the OS. While it is not necessary for using a backup function in conjunction with Shadow Copies, it is recommended because of the additional stability and reliability it provides. They’re not delta files.
Q.10 What do you understand about /etc/passwd?
/etc/passwd can be considered as the primary file in Unix/Linux operating system that is used for storing information about user accounts and can be read by all users. /etc/shadow is mostly used by the operating system instead due to security concerns and increased hashing capabilities.
Q.11 Define VoIP.
Voice over Internet Protocol (VoIP) refers to the technology used for sending your voice (analog data) across the internet (digital data) to an end-user. Further, it allows users for using the Internet as the transmission medium for voice calls at a very low cost.
Q.12 Explain Interior and Exterior Routing Protocols.
Interior routing protocol was designed and intended for use inside a single autonomous system. And, the exterior routing protocol was designed and intended for use between different autonomous systems.
Q.13 What do you understand about OSPF Neighbors?

OSPF neighbour can be stated as from one router’s viewpoint, another router that connects to the same data link with which the first router can and should exchange routing information using OSPF.

  • Firstly, neighbours examine and verify basic OSPF settings before exchanging routing information settings that must match for OSPF to work correctly.
  • Secondly, the ongoing process of one router knowing when the neighbour is healthy, and when the connection to a neighbour has been lost, tells the router when it must recalculate the entries in the routing table for reconverging to a new set of routes.
  • Additionally, the OSPF Hello process specifies how neighbours can be dynamically located. That is to say, new routers can be added to a network without needing every router to be reconfigured.
Q.14 Define VLAN Trunking Protocol.
VTP (VLAN Trunking Protocol) is used for maintaining VLAN configuration consistency over the entire network. This uses Layer 2 trunk frames for managing the addition, deletion, and renaming of VLANs on a network-wide basis from a centralized switch in the VTP server mode. Further, it is responsible for synchronizing VLAN information inside a VTP domain and lowers the requirements for configuring the same VLAN information on each switch. Further, it provides benefits like: VLAN configuration consistency over the network The mapping scheme for enabling VLAN to be trunked over mixed media Appropriate tracking and monitoring of VLANs Dynamic reporting of added VLANs over the network Plug-and-play configuration while adding new VLANs
Q.15 Define frame relay.
Frame Relay refers to a data link layer digital packet-switched network protocol technology designed for connecting local area networks (LANs) and transferring data over wide area networks (WANs). Frame Relay shares some of the same underlying technology as X.25.
Q.16 Explain the working of Frame Relay.

Frame Relay supports the multiplexing of traffic from multiple connections across a shared physical link. This uses hardware components that include router frames, bridges, and switches for packing data into individual frame relay messages. However, every connection uses a 10-bit Data Link Connection Identifier (DLCI) for unique channel addressing. Further, there are two types of connections:

  • Firstly, Permanent Virtual Circuits (PVCs) for persistent connections that are planned to be maintained for long periods even if data is not actively transferred.
  • Secondly, Switched Virtual Circuits (SVCs) for temporary connections that last only one session.
Q.17 Define routers.
Routers can be used for connecting two or more network segments. These can be considered as intelligent network devices that store information in their routing tables like paths, hops, and bottlenecks. Moreover, using this information, they can direct for the best path for data transfer. However, the routers operate at the OSI Network Layer.
Q.18 Define HTTP. What port does it use?
HTTP stands for HyperText Transfer Protocol which is responsible for web content. However, many web pages are using HTTP that helps in transmitting the web content and allowing the display and navigation of HyperText. It is the primary protocol and the port used here is TCP port 80.
Q.19 What do you understand about Ipx?
IPX or Internetwork Packet Exchange refers to a set of packet-switching and packet-sequencing protocols designed for functioning in small and large networks. In the OSI model, IPX is the network layer protocol in the Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX) protocol stack, which is primarily used on Novell Netware operating systems. This also provides peer-to-peer support connectivity.
Q.20 What do you understand about tracert?
Tracert refers to a Windows utility program that can be used for tracing the route taken by data from the router to the destination network. This displays the number of hops taken during the entire transmission route.
Q.21 Explain the term router on a stick.
Router-on-a-stick is used for describing a setup up that contains a router and switch connected using one Ethernet link configured as an 802.1q trunk link. In this setup, the switch is configured with multiple VLANs and the router executes all routing between the different networks/VLAN.
Q.22 Name the layers of the OSI reference model.

The OSI layers are:

  • Physical Layer
  • Data Link Layer
  • Network Layer
  • Transport Layer
  • Session Layer
  • Presentation Layer
  • Application Layer.
Q.23 Define switch.
The switch is used for receiving the signal to create a frame. This forwards the packets between various LAN segments. Moreover, it supports packet control when the data is sent to the Data Link layer or Network layer of the OSI model. However, while sending packets, the signal gets allowed and can be accessed by reading the destination address and so in order for forwarding the frame to the appropriate frame we use switches.
Q.24 Differentiate between Switch, Routers, and Hub.
The switch is used for receiving the signal to create a frame. This forwards the packets between various LAN segments. Moreover, it supports packet control when the data is sent to the Data Link layer or Network layer of the OSI model. However, while sending packets, the signal gets allowed and can be accessed by reading the destination address and so in order for forwarding the frame to the appropriate frame we use switches. Routers can be used for connecting two or more network segments. These can be considered as intelligent network devices that store information in their routing tables like paths, hops, and bottlenecks. Moreover, using this information, they can direct for the best path for data transfer. However, the routers operate at the OSI Network Layer. A Hub refers to a networking device that allows you to connect multiple PCs to a single network. However, if anything comes in its port then it sends it out to the others. And, it is less expensive and the least complicated.
Q.25 What do you understand about Network Congestion?
This refers to the process in which a network node is carrying more data that can’t be managed on the network, and due to which loss of packets or information takes place on the network node and the receiver can’t receive appropriate information.
Q.26 Explain the various types of networks?

The network can be classified as:

1. PAN (Personal Area Network) This consists of devices used by a single person with having a range of a few meters.

2. WPAN (Wireless Personal Area Network) This uses wireless technologies as a medium.

3. LAN (Local Area Network) This network has a range limited to a relatively small area like a room, building, airplane, etc.

4. WLAN (Wireless Local Area Network) This refers to a LAN network that uses wireless means of communication. This is the most used network because of its scalability and no requirement for the installation of cables.

5. CAN (Campus Area Network) This refers to a network of high-speed devices that connects LANs in a limited geographical area like a university campus.

6. MAN (Metropolitan Area Network) This is a high-speed (broadband) network providing coverage in a larger geographic area.

7. WAN (Wide Area Network) This expands across a large geographical area using unusual means of communication like satellites or fiber optics. 8. VLAN This is a type of logical or virtual LAN, mounted on a physical network that is used for increasing security and performance.

Q.27 What is an IP Address?

IP address can be considered as an identifier used for allowing the information to be sent between devices available on a network. Secondly, they consist of location information and make devices accessible for communication. Further, it has two principal functions which include host and location address. And, there are two versions of IP which are

  • IPv4 (32-bits)
  • IPv6 (128-bits).
Q.28 Define Unicast, Multicast, Broadcast, and Anycast.
  • Unicast refers to the exchange of messages between a single source and a single destination. In this, packets are sent from the sender containing the data address of the receiver so that it can go to the receiver directly.
  • The broadcast can be considered as the exchange of messages between one sender to all possible multiple receivers. However, this operates only on a local network. The Broadcasting of data cannot be executed on the public internet due to a massive amount of unrelated and unnecessary data.
  • Multicast refers to the exchange of messages between one sender and multiple receivers. In this, the network settings discover your receiving clients and sort of broadcasting.
  • Anycast can be considered as the exchange of messages between one host to another host. It uses TCP and UDP protocols. Further, the copy of each data packet goes to every host that requests it.
Q.29 Define Topology and is type.

Topology refers to an arrangement of elements in a specific order. The types include:

1. Bus - In the bus network topology, every workstation is connected to a main cable called a bus.

2. Star - In the star network topology, there is a central computer or server to which all workstations are directly connected. Each workstation is indirectly connected to the other via the central computer.

3. Ring - In the ring network topology, the workstations are connected in a closed-loop configuration. However, adjacent workstation pairs are directly connected and other pairs of workstations are indirectly connected, passing data via one or more intermediate nodes.

4. Mesh - Mesh network topology has two forms: Firstly, full mesh topology, in which every workstation is directly connected to each other. Secondly, partial mesh topology, in which some workstations are connected to all the others, and some are connected only to the other nodes with which they exchange more data.

5. Tree - The tree network topology uses two or more star networks connected to each other. The central computers in star networks are connected to the main bus.

6. Signal - Signal or Logical topology refers to the nature of the paths that signals follow from node to node. In many cases, the logical topology is the same as the physical topology.

Q.30 What do you understand about ARP and RARP.
ARP stands for Address Resolution Protocol which is used for mapping an IP address to a physical machine. And, RARP stands for Reverse Address Resolution Protocol which is used for mapping MAC address to the IP address.
Q.31 Differentiate between static and dynamic IP addresses.
The static IP address will not change over time and is reserved statically whereas the dynamic IP address changes each time when you connect to the Internet.
Q.32 What do you understand about peer to peer?
Peer-to-peer (P2P) are networks that do not depend on a server. In other words, all PCs on the network act as individual workstations. Further, this contains he distributed and decentralized network where individual nodes in the networks act as both suppliers and consumers of the resources.
Q.33 Define Inter-VLAN Routing.
Virtual LAN (VLANs) separates one physical network into multiple broadcast domains. But, VLAN-enabled switches cannot, by themselves, forward traffic over VLANs boundaries. So it is required to have routing between these VLANs which is known as inter-VLAN routing.
Q.34 Define print server and a network-attached printer.
A print server can be considered as: Firstly, an actual server sharing out many different printers from a central administration point Secondly, a small dedicated box that allows a legacy printer for connecting to a network jack. On the other hand, a network-attached printer contains a network card built into it. Moreover, it can provide benefit from the former, as network-attached printers are extremely useful in a corporate environment since they do not need the printer to be connected directly to a single user's system.
Q.35 Differentiate between a packet switch and circuit switch network.
For making a baseband network practical for many computers to share, the data transmitted by every system is divided into separate units called packets. When a computer transmits data it might be divided into many packets, and the computer transmits every packet separately. When all of the packets constituting a particular transmission reach their destination, the receiving computer reassembles them back into original data. On the other hand, circuit-switching can be defined as when the two systems wanting to communicate for establishing a circuit before they transmit any information. That circuit remains open throughout the life of the exchange and is only broken when the two systems are done communicating. This is more common in environments like the public switched telephone network (PSTN).
Q.36 Define FTP.
FTP stands for File Transfer Protocol which is primarily designed for large file transfers, with the capability of resuming downloads if they are interrupted. However, access to an FTP server can be achieved using two different techniques: Anonymous access and Standard Login. Further, the two competing implementations of FTP that take care of the issue are SFTP (FTP over SSH) and FTPS (FTP with SSL). FTP uses TCP ports 20 and 21.
Q.37 Can I use external media like tapes or harddisks for backups?
Hard disk is the best option here. As external Media has been used for backups for a very long time but has started to fall out of favor in the past few years due to its speed limitations. However, tapes have been particularly slow even before the jump to the terabyte era. On the other hand, removable hard disks have been able to pick up on this trend, however, as capacity and price have given them a solid lead in front of other options. Moreover, removable hard disks now have the capability of connecting very rapidly, even without the use of a dedicated hot-swap drive bay.
Q.38 Describe the types of UTP Cables.

UTP (Unshielded Twisted Pair) cable comes in a variety of different grades, called "categories" by the Electronics Industry Association (EIA) and the Telecommunications Industry Association (TIA), the combination being referred to as EIA/TIA. This include Firstly, Cat

1. Used for voice-grade telephone networks only. Secondly, Cat

2. Used for voice-grade telephone networks. Then, Cat

3. Used for voice-grade telephone networks, 10 Mbps Ethernet, 4 Mbps Token Ring, Cat

4. Used for 16 Mbps Token Ring networks Cat

5. Used for 100BaseTX Fast Ethernet, SONET, and OC-3 ATM Lastly, Cat 5e. Used for Gigabit (1000 Mbps) Ethernet protocols

Q.39 Define DHCP.
DHCP stands for Dynamic Host Configuration Protocol. This is used for allocating an IP address to devices over the network automatically. This examines for the next available address not yet taken by any device, then allocated this to a network device.
Q.40 What do you understand about DNS?
The Domain Name System (DNS) is a core part of the internet, providing a way to match names to numbers. Anything connected to the internet laptops, tablets, mobile phones, and websites contains an Internet Protocol (IP) address made up of numbers.
Q.41 Differentiate between ifconfig and ipconfig.
ipconfig can be considered as the primary network connection troubleshooting and information tools available for Windows Operating Systems. This provides user access for seeing what the current information is, forcing a release of those settings if set by DHCP and clearing out the local DNS cache among other functions it is able to handle. Whereas ifconfig is a similar utility for Unix/Linux systems which is identical at first but it actually isn't. This provides quick access to network connection information. And, it does not allow for the DHCP functions that ipconfig does. However, these functions in fact are controlled by a separate service/daemon called DHCPD.
Q.42 Define port forwarding.
While trying to communicate with systems within a secured network can be very difficult to do so from the outside. For this, using a port forwarding table inside the router itself or other connection management device can allow for defined traffic to be automatically forwarded on to a particular destination. For example, if you had a web server running on your network and you wanted access to be provided to it from the outside, you would set up port forwarding to port 80 on the server in question. This means that anyone placing at your IP address in a web browser would be connected up to the server's website immediately.
Q.43 Explain the use of a cross and straight cable.
A straight-through cable is used for DTE-to-DCE connections. For example, Firstly, a hub to a router, PC, or file server. Secondly, a switch to a router, PC, or file server. And, a crossover cable should be used when you connect a DTE to another DTE or a DCE to another DCE. For example, Firstly, a hub to another hub. Secondly, a switch to another switch. Then, a hub to a switch. Lastly, a PC, router, or file server to another PC, router, or file server.
Q.44 Define port number/socket number and connection multiplexing?
The transport layer allocated a unique set of numbers for each connection. These numbers are called port or socket numbers. And, TCP, and UDP, provide a multiplexing function for a device that allows multiple applications to simultaneously send and receive data.
Q.45 What do you understand about Bandwidth.?
Bandwidth is defined as the amount of data that can be transmitted or carried in a fixed interval of time.
Q.46 Explain the use of the data link layer.
The datalink layer is used for checking whether messages are sent to the right devices. Another function of the data link layer is framing.
Q.47 Define the term RAS.
RAS stands for Remote Access Services that refers to any combination of hardware and software for enabling remote access to tools or information that typically occupies a network of IT devices.
Q.48 What do you understand about half-duplex and full-duplex?
Half-duplex refers to the mode of communication between two devices. In this, the data flow is bi-directionally but simultaneously. An example of a half-duplex is a walkie-talkie. And, full-duplex refers to a mode of communication between two devices and the data flow is bi-directional too, but the flow is simultaneous. For example, telephone.
Q.49 Define Netstat.
Netstat is basically a command-line utility program used for providing information about the current Transmission Control Protocol /Internet Protocol (TCP/IP) settings of a connection.
Q.50 Explain the term NAT.
NAT stands for Network Address Translation. This is basically a protocol that enables a network device, usually a firewall, for allocating a public address to a computer/s inside a private network.
Q.51 Which IOS command is used to monitor ipx traffic on an network?
show ipx traffic
Q.52 Which command will allow for both sap and Novell-ether encapsulations on one Ethernet interface of the Cisco router?
interface ethernet 0.1ipx encapsulation Novell-ether ipx network 9e interface ethernet 0.2 ipx encapsulation sap ipx network 6c
Q.53 What is the duration in seconds for update of routing tables under Novell’s implementation of RIP?
Q.54 Which metric is used to make routing decisions for Novell’s use of RIP?
Q.55 Link-state routing is provided by which NetWare protocol?
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