Terms

Question 1

Router

Answer 1

A router is specialized computer connected to more than one network running software that allows the router to move data from one network to another. Routers operate at the network layer (OSI Model’s layer 3). The primary function of a router is to connect networks together and keep certain kinds of broadcast traffic under control.

Question 2

Switch

Answer 2

A network switch is a small hardware device that joins multiple computers together within one local area network (LAN). Technically, network switches operate at layer two (Data Link Layer) of the OSI model.

Question 3

LAN

Answer 3

A local area network (LAN) is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building using network media (wire, fibre, air).
The defining characteristics of LANs, in contrast to wide area networks (WANs), include their usually
a) higher data-transfer rates,
b) smaller geographic area, and
c) lack of a need for leased telecommunication lines.

Question 4

Virtualisation

Answer 4

Virtualization is the process of separating the software layer of a computer or server from the hardware layer of a computer or server. A new layer is placed between the two to act as a go between.

Think of the car pool analogy.

The thing we are really talking about here is Server Virtualization. The hardware or the vehicles are called Hosts. The software or the passengers are called Clients. A single Host can support multiple Clients through the use of Virtualization software like VMWare.

Question 5

Firewall

Answer 5

A firewall can either be software-based or hardware-based and is used to help keep a network secure. Its primary objective is to control the incoming and outgoing network traffic by analyzing the data packets and determining whether it should be allowed through or not, based on a predetermined rule set. A network’s firewall builds a bridge between an internal network that is assumed to be secure and trusted, and another network, usually an external (inter)network, such as the Internet, that is not assumed to be secure and trusted.[1]

Question 6

What is a broadcast domain

Answer 6

A broadcast domain is a logical division of a computer network, in which all nodes can reach each other by broadcast at the data link layer.

A broadcast domain can be within the same LAN segment or it can be bridged to other LAN segments.

Question 7

What is a VLAN

Answer 7

A virtual local area network, virtual LAN or VLAN is a concept of partitioning a physical network, so that distinct broadcast domains are created. This is usually achieved on switch or router devices.
It allows an administrator to group together stations by logical function, or by applications, without regard to physical location of the users.
Each VLAN functions as a separate LAN.

Question 8

What 3 major functions has a VLAN

Answer 8

A VLAN has three major functions:

i. Limits the size of broadcast domains
ii. Improves network performance
iii. Provides a level of security

Question 9

What is the difference between a router and a switch

Answer 9

A network router is a more sophisticated network device compared to either a network switch or a network hub.
Switches connect computers together within the same network, while routers connect entire networks together.

Question 10

What is the MAC address

Answer 10

the Media Access Control (MAC) address is every bit as important as an IP address.
The MAC address is a unique value associated with a network adapter. MAC addresses are also known as hardware addresses or physical addresses. They uniquely identify an adapter on a LAN.

Question 11

Why MAC addresses

Answer 11

Recall that TCP/IP and other mainstream networking architectures generally adopt the OSI model. In this model, network functionality is subdivided into layers. MAC addresses function at the data link layer (layer 2 in the OSI model). They allow computers to uniquely identify themselves on a network at this relatively low level.

Question 12

MAC vs. IP Addressing

Answer 12

Whereas MAC addressing works at the data link layer, IP addressing functions at the network layer (layer 3). It’s a slight oversimplification, but one can think of IP addressing as supporting the software implementation and MAC addresses as supporting the hardware implementation of the network stack. The MAC address generally remains fixed and follows the network device, but the IP address changes as the network device moves from one network to another.

Question 13

What is ARP

Answer 13

IP networks maintain a mapping between the IP address of a device and its MAC address. This mapping is known as the ARP cache or ARP table. ARP, the Address Resolution Protocol, supports the logic for obtaining this mapping and keeping the cache up to date.

Question 14

Ethernet

Answer 14

Ethernet is a physical and data link layer technology for local area networks (LANs).

Question 15

Hot swapping

Answer 15

Hot swapping and Hot plugging are terms used to describe the functions of replacing computer system components without shutting down the system.

Question 16

What is a cold start and a warm start

Answer 16

A cold start is booting up from a power off condition. A warm start is restarting the computer without turning the power off.

Question 17

What is a SAN

Answer 17

A storage area network (SAN) is a high-speed special-purpose network (or subnetwork) that interconnects different kinds of data storage devices with associated data servers on behalf of a larger network of users.
A storage area network (SAN) is a dedicated network that provides access to consolidated, block level data storage. SANs are primarily used to make storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear like locally attached devices to the operating system. A SAN typically has its own network of storage devices that are generally not accessible through the local area network by other devices.

Question 18

Redundancy

Answer 18

In information technology, the term redundant has several usages:

1) Redundant describes computer or network system components, such as fans, hard disk drives, servers, operating systems, switches, and telecommunication links that are installed to back up primary resources in case they fail. A well-known example of a redundant system is the redundant array of independent disks (redundant array of independent disks).
2) Redundant information is unneeded or duplicated information.
3) Redundant bits are extra binary digits that are generated and transferred along with a data transfer to ensure that no bits were lost during the data transfer.

Question 19

MPLS

Answer 19

The key thing to remember about MPLS is that it’s a technique, not a service — so it can be used to deliver anything from IP VPNs to Metro Ethernet services, or even to provision optical services.
Multiprotocol Label Switching (MPLS) is a mechanism in high-performance telecommunications networks that directs data from one network node to the next based on short path labels rather than long network addresses, avoiding complex lookups in a routing table.
MPLS is a packet-forwarding technology which uses labels to make data forwarding decisions. With MPLS, the Layer 3 header analysis is done just once (when the packet enters the MPLS domain). Label inspection drives subsequent packet forwarding.

Question 20

RAID

Answer 20

RAID (redundant array of independent disks, originally redundant array of inexpensive disks[1][2]) is a storage technology that combines multiple disk drive components into a logical unit. Data is distributed across the drives in one of several ways called “RAID levels”, depending on what level of redundancy and performance (via parallel communication) is required.

Question 21

Virtual machine

Answer 21

A virtual machine (VM) is a software implementation of a computing environment in which an operating system (OS) or program can be installed and run.

The virtual machine typically emulates a physical computing environment, but requests for CPU, memory, hard disk, network and other hardware resources are managed by a virtualization layer which translates these requests to the underlying physical hardware.

VMs are created within a virtualization layer, such as a hypervisor or a virtualization platform that runs on top of a client or server operating system. This operating system is known as the host OS. The virtualization layer can be used to create many individual, isolated VM environments.

Typically, guest operating systems and programs are not aware that they are running on a virtual platform and, as long as the VM’s virtual platform is supported, this software can be installed in the same way it would be deployed to physical server hardware. For example, the guest OS might appear to have a physical hard disk attached to it, but actual I/O requests are translated by the virtualization layer so they actually occur against a file that is accessible by the host OS.

Question 22

Network Adapter/Network Interface Card (NIC)

Answer 22

A device that enables you to send and receive data to and from your computer.

Question 23

Broadcast

Answer 23

The data is sent to every host on the network.