Networking and Hosting

Question 1

What is a network packet?

Answer 1

Formatted unit of data carried by a packet-switched network.

It consists of control information and user data.

Question 2

What does a hub do?

Answer 2

Broadcasts to all ports at the physical layer.

Question 3

What does a switch do?

Answer 3

Knows which port to send the message to working at the data link layer and sometimes the network layer.

Question 4

What does a router do?

Answer 4

Routes packets until they reach their destination.

Question 5

What is the difference between bridging and routing?

Answer 5

Bridging passes all network traffic whereas routing only handles “directed” traffic.

Question 6

Name 5 network topologies.

Answer 6

Bus
Ring
Star
Tree
Mesh

Question 7

What does a routing table determine?

Answer 7

The forwarding or next-hop IP address.

The interface to be used for the forwarding.

Question 8

What do you need to be aware of when connecting to a medical network?

Answer 8

Firewalls.
Only allowing predefined IP addresses through.
Port numbers.
The direction the message is travelling in.
Whether the incoming message is a reponse to an outgoing one (e.g. a web page).
Specific exceptions to the rule.
Packet filtering - the header of the packet is examined in order to extract the information required for the rules.

Question 9

What is the OSI 7-layer model?

Answer 9

Physical
Data link
Network
Transport
Session
Presentation
Application

Question 10

What is the physical layer in the OSI 7-layer model?

Answer 10

It is concerned with the transmission and reception of unstructured raw bit steam over a physical medium.

Question 11

What does the data link layer in the OSI 7-layer model do?

Answer 11

Provides error-free transfer of data frames from one node to another over the physical layer.

Question 12

What does the network layer in the OSI 7-layer model do?

Answer 12

Controls the operation of the subnet, deciding which physical path the data should take.

Question 13

What does the transport layer in the OSI 7-layer model do?

Answer 13

Ensures messages are delivered error-free.

Question 14

What does the session layer in the OSI 7-layer model do?

Answer 14

Establishes a session between processes running on different stations.

Question 15

What does the presentation layer in the OSI 7-layer model do?

Answer 15

Formats the data to be presented to the application layer. It can be viewed as the translator for the network.

Question 16

What does the application layer in the OSI 7-layer model do?

Answer 16

Serves as the window for users and application processes to access network services.

Question 17

What is a packet?

Answer 17

Refers to a data unit at the network layer.

Question 18

What are the benefits of cloud computing?

Answer 18

System prototyping and evaluation.
Reduction of costs.
Flexibility.
Universal access.
Up to date software.
Choice of software.
Potential to be greener and more economical.

Question 19

What are the advantages of virtualisation?

Answer 19

Lower power consumption.
Less cooling required.
Less rack space.
Centralised administration.
Quick and efficient (just copy another virtual machine).
Easier backup and disaster recovery.

Question 20

What is a public cloud?

Answer 20

A service provider makes resources, such as application and storage, available to the general public over the Internet. They may be free or offered on a pay-per-usage model.

Question 21

What is a private cloud?

Answer 21

A type of cloud computing that delivers similar advantages to public cloud, including scalability and self-service, but through proprietary architecture. Unlike public clouds, which deliver services to multiple organisations, a private cloud is dedicated to a single organisation.

Question 22

What is a hybrid cloud?

Answer 22

A cloud computing environment which uses a mix of on-premises, private cloud and third-party, public cloud services with orchestration between the two platforms. By allowing workloads to move between private and public clouds as computing needs and costs change, hybrid clouds give businesses greater flexibility and more fata deployment methods.

Question 23

Privacy and security issues in Web applications?

Answer 23

Internal procedures or staff are often a reason for data leakage.
- Poor access management.
- Lack of awareness.
- Weak anonymization of personal data.
Automatic session timeout and a highly visible logout button is security state-of-the-art.

Question 24

What is metadata in DICOM?

Answer 24

The supporting details allowing meaningful clinical use of an image.

Question 25

What 2 things are presented by the DICOM standard?

Answer 25

An information model for clearly describing all the real-world concepts in medical imaging.
A technical implementation to turn this model into bytes for storage or network exchange.

Question 26

What is Planned Preventative Maintenance?

Answer 26

Inspecting, calibrating and testing all of the hospitals medical equipment is not a minor task. Most services spread the load across the entire year. The management system is also able to assist in planning by reporting on peaks and troughs in the anticipated workload, adjusted for planned staff absenses and potential peaks and troughs in emergency repair (from historal data).

Question 27

How can WiFi be used to track devices?

Answer 27

Tags transmit a WiFi signal which is picked up by the WiFi access points. If the signal is picked up by four or more access points, the location of the device can be triangulated to three dimensions.

Question 28

How can radio frequency identification (RFID) be used to track devices?

Answer 28

A network of RFID receivers are positioned across the organisation, connected to the LAN. Tags communicate with these receivers who can track their location. Passive tags respond to a signal from gateways (where they also draw their power) whereas active ones transmit data to a nearby receiver and have on board power.

Question 29

How can RFID with IR (infra-red) be used to track devices?

Answer 29

This used RFID technology supplemented with IR transmitters/detectors. IR can be used to track devices to a very granular level (bed space, or even drawer), and information is then communicated centrally via an RFID network.