1. 1 Mark Gleeson gleesoma@cs.tcd.ie (01) 896 2666 Distributed Systems Group, Trinity College, Dublin 14.02.2009 Diploma in Health Informatics Networks

2. 2 Objectives Understand some network terminology- enough to be able to read further on the topic. Understand some issues of network design. Issues concerning application of networking to health. Emphasis on practical aspects

3. 3 Introduction to Networks 1.Introduction 2.Network characteristics 3.Network Software 4.Network Hardware 5.Security 6.Internet and the World Wide Web 7.Telemedicine

4. 4 Section 1 – Introduction - Network Basics What is a network? What does it do? How useful is the network Various key attributes

5. 5 Introduction (1/2) In the 20th Century key technologies were employed for information gathering, processing and distribution. Some developments include –worldwide telephone networks –the invention of television and radio –the unprecedented growth of the computer industry –launching of communication satellites These areas are converging. The convergence of computers and communications is very significant.

6. 6 Introduction (2/2) Initially computers were highly centralized, usually within a single room. Computers were physically large. The development and advances made in the computer industry are huge. Now – lots of small independent computers communicating to do a job. These are called Computer Networks

7. 7 What is a Computer Network? (1/2) An interconnected collection of computers which are: –Co-operative Co-operative action is required between the components –Autonomous All components are capable of independent action Any resource is capable of refusing requests –Mutually Suspicious Components verify requests

8. 8 What is a Computer Network? (2/2) Any computer connected to a network is known as a host. –Local host Your own computer –Remote host The computer elsewhere you are in contact with There are hardware and software aspects to computer networks

9. 9 (Digital) Bandwidth The amount of data per second a communications link can carry Typically referred to in bits per second –Note 1 byte == 8 bits The actual amount of useful data you can send will be less than the actual capacity –Overheads for Addressing Routing Error detection Medium access

10. 10 Latency/ Delay Measure of the delay from sending a piece of data or request until it is processed at the destination –Exceptionally important for Video and audio –Voice over IP, Skype, Video conferencing Interactive systems –Inquiry based systems – patent records –Booking systems Needs careful investigation to determine the weak points –Is it the network or the computer?

11. 11 More Terminology Attenuation –Measure of how much a signal degrades per distance in a certain medium Different cable types have difference values Attenuation limits the distance you can communicate over Electro Magnetic Interference - EMI –Electrical noise artificially generated Watch out for high powered electrical equipment –MRI machines, Trams, Electric trains, Microwaves Of particular concern in wireless networks –Microwaves operate at a frequency used by 802.11b/g

12. 12 Section 2 - Network characteristics What Are Networks Network Types and Topologies Communication concepts Basic Message Types

13. 13 What are Networks? Tanenbaum’s definition: "A network is an interconnected collection of autonomous computers" IPv4 IPv6 ATM TCP/IP RIP OSPF ???

14. 14 Types of Networks Bus-based networks –Original Ethernet (802.3) Star-based networks –Switched (Modern) Ethernet (802.3ab) Ring-based networks –FDDI –Token Ring (802.5) Wireless networks –WiFi (802.11a/b/g/n), Bluetooth, Hyperlan IrDA, WiMax, GSM, EDGE,3G

15. 15 LAN Topologies Bus architecture (Ethernet) Ring architecture (Token Ring) Star architecture (switched Ethernet) Double ring architecture (FDDI)

16. 16 Types of Networks Classification based on diameter: 1 m System 10 mRoom 100 mBuilding 1 kmCampus 10 kmCity 100 kmCountry 1,000 kmContinent 10,000 kmPlanet Multi-processor LAN (Local Area Networks) MAN (Metropolitan Area Networks) WAN (Wide Area Networks) The Internet PAN (Personal Area Networks)

17. 17 Local-Area Networks (LANs) * Figure is courtesy of B. Forouzan

18. 18 Wide-Area Networks (WANs) Latency Administration/Jurisdiction * Figure is courtesy of B. Forouzan

19. 19 Simplex * Figure is courtesy of B. Forouzan

20. 20 Duplex Half-Duplex Full-Duplex * Figure is courtesy of B. Forouzan

21. 21 Point-to-Point & Multipoint * Figure is courtesy of B. Forouzan

22. 22 Basic Message Types Three basic message types –1. Unicast - one sender to one receiver Sender Receiver

23. 23 Basic Message Types Three basic message types –1. Unicast - one sender and one receiver –2. Broadcast - one sender, everybody receives Broadcast addresses: –network ID + –all bits of host ID set –e.g. 134.226.255.255 Sender

24. 24 Three basic message types –Unicast - one sender and one receive –Broadcast - one sender, everybody receives –Multicast - one sender and a group of receivers Basic Message Types Sender Receivers

25. 25 Section 3 - Network Software Originally hardware matters were the main focus when building networks the software was an afterthought. Key Network Software concepts: –Layers –Protocols –Interfaces –Services

26. 26 Layers The idea of introducing layers of software reduces the design complexity. It divides the large problem into smaller ones. The number, name, contents and function of each layer vary from network to network. However for each network the idea is that one layer offers something to a second layer without the second layer knowing how the first layer is implemented.

27. 27 Protocols Provided two networks adhere to the same set of layers layer n on one machine can (virtually)communicate with layer n on another machine. The rules and conventions used in this conversation are known as the layer n protocol. A protocol is an agreement between the communicating parties as to how the communication proceeds.

28. 28 Interfaces Interfaces exist between adjacent layers. The interface specifies what one layer is offering to the other layer. Analogous to Object-Oriented concept of Encapsulation One of the most important aspects of designing the network software is to provide clean, well understood interfaces. Minimise the amount of information that has to be passed from layer to layer. Once a layer’s interface is defined many implementations of that layer can exist. The only stipulation is that the interface is adhered to.

29. 29 Design Issues for the layers Addressing – identifying senders and receivers. Data transfer rules- Simplex, half duplex, Full duplex. Error control - Agree on a protocol. Implementation of the protocol. Order of the messages Fast sender swamping a slow receiver - feedback or an agreed size is required. Length of messages - Too large/too small. Multiplexing - use the channel for multiple unrelated conversations. Multiple routes - How to choose the route. Physical and logical choices.

30. 30 Reference Models Two reference models are considered –The OSI (Open Systems Interconnection) Reference Model –initiated in the 1970s matured in the late 1980s and early 1990s –TCP/IP initiated through work carried out in the late 1960s, matured and adopted in early 1990s

31. 31 Open Systems Interconnetion Model Developed by the International Standards Organisation (ISO) The model deals with connecting open systems i.e. systems that are open for communication with other systems.

32. 32 Principles used to arrive at the Seven Layer Architecture A layer should be created where a different level of abstraction is needed. Each layer should perform a well defined function Standardisation issues. Minimise data that has to travel between the layers Large enough number of layers to support distinct functionality but not too large a number to create an unwieldy architecture

33. 33 Network Protocols Common “language” on the network Define network components’ interactions –Actions/requests –Responses Defined in standards –ISO Standards –IEEE Standards (mainly at physical and mac) –ITU Recommendations –IETF Request For Comments (RFC)

34. 34 The TCP/IP Reference model The grandparent of all computer networks the Arpanet – research network sponsored by the Department of Defence (DoD) in America. The network used leased lines to connect government offices and universities together. When satellite and radio networks appeared there were problems. The thinking for TCP/IP began. TCP/IP is named after its two primary protocols. –TCP- Transmission Control Protocol –IP- Internet Protocol A layered architecture used to connect multiple networks together in a seamless way was one of the design goals from the very beginning Connections should remain intact even if there was some subnet damage.

35. 35 The Physical Layer The Physical Layer is the lowest layer and is concerned with wiring and electrical standards. The design issues have to do with making sure that when a sender sends a 1 bit that the receiver receives a 1 bit and not a 0 bit. Example issues to be agreed when building this layer –How many volts to represent a 1 –How many volts to represent a 0 –How many microseconds a bit lasts. –Does transmission proceed simultaneously in both directions –How are connections established and torn down –How many pins are on connectors and what each pin does. –What kind of transmission medium, wired, fiber optic

36. 36 Communication between End-Systems * Figure is courtesy of B. Forouzan

37. 37 Data Link Layer * Figure is courtesy of B. Forouzan

38. 38 Duties of the Data Link Layer The data link layer is responsible for transmitting frames from one node to the next on the same network. * Figure is courtesy of B. Forouzan

39. 39 Packetizing & Addressing Packetizing: Encapsulating data in frame or cell i.e. adding header and trailer Addressing: Determining the address of the next hop (LANs) or the virtual circuit address (WANs) * Figure is courtesy of B. Forouzan

40. 40 Error Control & Flow Control Error Control: Detect errors in received data and attempt to correct them –Error Detection –Error Correction Flow Control: Prevent the sender from overwhelming the receiver –Go-back-N –Sliding Window

41. 41 Medium Access Control Control the access to a shared medium to prevent conflicts and collisions –Aloha –CSMA/CD or CSMA/CA * Figure is courtesy of B. Forouzan

42. 42 Analogy: Point-to-Point Communication Simple Synchronization AliceBob Phone conversation

43. 43 Analogy: Shared Medium Synchronisation is more complex

44. 44 Asynchronous Systems Round robin –Good if many stations have data to transmit over extended period Reservation –Good for stream traffic e.g audio, video Contention –Good for bursty traffic –All stations contend for time –Distributed –Simple to implement –Efficient under moderate load –Tend to collapse under heavy load

45. 45 Multiple-Access Protocols * Figure is courtesy of B. Forouzan

46. 46 LAN Technologies - Ethernet Developed by Metcalfe 1972/3 while at Xerox PARC Standards in 1978, 1995, 1998 Types of Ethernet –Original Ethernet –Switched Ethernet –Fast Ethernet –Gigabit Ethernet Medium Access Control –CSMA/CD IEEE 802.2: Logical Link Control Metcalfe’s Ethernet sketch

47. 47 LAN Technologies - Evolution of Ethernet 1972/73 defined for coaxial cable Fast Ethernet used mainly unshielded twisted pair (UTP) Gigabit Ethernet now common in desktops and laptops 10GB Ethernet used mainly for backbone

48. 48 802.3 MAC Frame 64-bit frame preamble (10101010) used to synchronize reception –7 bit preamble (10101010) + 1 start flag (10101011) Maximum frame length: 1518 bytes  max 1500 bytes payload Minimum frame length: 64 bytes  min 46 bytes payload * Figure is courtesy of B. Forouzan

49. 49 Ethernet Addresses – The ‘MAC’ Address A unique 48 bit long number –Eg 00:A0:4A:21:19:13 Types of Addresses: –Unicast – delivered to one station –Multicast – delivered to a set of stations 01-80-C2-00-00-00 Spanning tree (for bridges) 03-00-00-00-00-01 NETBIOS –Broadcast – delivered to all stations FF-FF-FF-FF-FF-FF vendor-specific

50. 50 Non-bridged and Bridged Networks Extension of Networks: –Repeaters, Hubs- Physical Layer –Bridges, Switches- Data Link Layer –Routers- Network Layer Collision domains: –Collision affects all machines in one segment * Figure is courtesy of B. Forouzan

51. 51 Switched Ethernet Switch delivers packets to individual machines –Without affecting communication with other machines Collisions only occur on individual links * Figure is courtesy of B. Forouzan

52. 52 Full-duplex Switched Ethernet No collisions –One line to send –One line to transmit * Figure is courtesy of B. Forouzan

53. 53 Comms Rooms

54. 54 Switches in Comms Rooms

55. 55 Wireless (1/2) IEEE 802.11 standard of 1997 started the revolution with 2Mbps top speed –Now on 802.11g with 54Mbps –802.11n to promise 150+Mbps –Referred by some as Wireless Ethernet –Shares significant similarities with original bus style Ethernet Reliability and Performance much less than wired network –Current max speed 54Mbps shared by all on same base station –Prone to interference and poor reception –Speed drops under poor conditions to reduce errors –Range 100m+ in open much less in office situation

56. 56 Wireless (2/2) Star like network –Your laptop talks to a ‘access point’ which connects to your wired network –Laptop which move been access points to keep the strongest signal Uses the Industrial, Medical and Scientific Band –No licence needed –Healthcare staff should be aware this shared use and verify before installation that there won’t be a conflict Advantages –No need to install ethernet cabling everywhere –Network access everywhere in range

57. 57 The Network Layer The Network Layer is concerned with controlling the operation of the subnet. A key design issue is determining how packets are routed from source to destination. They can be static, dynamic. Example issues to be agreed when building this layer –Routing mechanisms –How is subnet congestion to be dealt with –How are costings included- national boundaries –Addressing mechanisms. –In broadcast networks the network layer may be very thin or non-existent.

58. 58 Position of the Network Layer Sends frames through data link layer Accepts data from transport layer

59. 59 Duties of Network Layer Problems the Network Layer needs to address: –Transfer over networks of various architectures –Addressing on a “global” scale –Adjusting to maximum transmission units Hop-to-hop delivery provided by data link layer Transfer of packets between end systems provided by network layer

60. 60 Switching in the Internet Connection-oriented communication –Connection exists between sender and receiver for duration of communication Connection-less communication –Data between sender and receiver

61. 61 The Scenario Computer A establishes IP address of Computer B Computer A creates IP packet with address of Computer B as destination and its own IP address as source Routers are responsible to direct packet towards destination Computer A Computer B

62. 62 The Scenario Best route: Smallest number of hops? Computer A Computer B

63. 63 The Scenario Best route: –Fastest round-trip time? –Highest Bandwidth? Computer A Computer B

64. 64 Routing Basics Routing Tables –Creating tables Dynamic vs. Static –Maintaining tables Periodic vs. Aperiodic Computer A Computer B node1 node2 node3 node1 node2 node3 node1 node2 node3 node6 node5 node7 node1 node2 node3 node8 node3 node5 node1 node2 node3 node8 node5 node1 node2 node3 node4 node5 node1 node2 node3 node1 node2 node3 node1 node2 node3 node1 node2 node3 node1 node2 node3 node1 node2 node3 node1 node2 node3 node1 node2 node3 node1 node2 node3 node1 node2 node3

65. 65 Structure of the Internet Autonomous Systems –e.g. Companies, ISPs, 3rd-level Institutions Autonomous Systems

66. 66 Autonomous Systems Stub network –Network that does not forward to other network Transit network –Network that forwards traffic between other networks Point-to-point link Stub Network Transit Network Point-to-Point

67. 67 Yet another Layer ?!? Transport Layer – TCP Why should you care? Applications use TCP as main communication mechanism –HTTP –Remote procedure calls (RPC) File Transfer

68. 68 Network Layer vs Transport Layer Network LayerTransport Layer Communication between two nodes Communication between processes Best effort deliveryOrdered, guaranteed delivery Connection-less communication Connection-oriented communication

69. 69 Transport Layer Process-to-Process Delivery

70. 70 IP Addresses & Port Numbers IP Addresses determine the host Port Numbers determine the application

71. 71 Communication at Transport Layer Comms at Transport Layer from port to port IP implementation multiplexes depending on protocol field in IP header

72. 72 Client-Server Paradigm Server Port 80 Port 14430 Port 12420 Client A Client B Port 14

73. 73 Problems Connection establishment Connection termination Ordered Delivery Retransmission strategy Duplication detection Crash recovery Flow control

74. 74 Section 4 - Network Hardware Connecting hosts and networks require hardware devices which include.. Networking and Internetworking Devices –Repeaters –Bridges –Hubs –Switches –Routers –Gateways –Brouters Modems Transmission Media

75. 75 Networking and Internetworking Devices These devices can be divided into 3 categories –Repeaters, –Bridges, –Routers and Gateways. Repeaters and Bridges are used at the Networking of hosts Routers and Gateways are used for Internetworking

76. 76 Repeaters and Bridges Repeaters –Operate at the physical layer. They regenerate signals. Bridges –Operate at the physical and data link layers. –They are used to divide a network into segments and can control traffic flow and are useful for securing the network. –They can also regenerate signals.

77. 77 What is a Switch A layer 2 device – Data Link Layer Builds a table of the MAC addresses of devices attached on each port ‘Store and Forward’ –Switch receives a packet –Verifies it is error free –Looks at its destination MAC –Sends the packet on ‘Cut Through’ –Starts to forward packet once it reads the destination address –No error checking Improved performance Photo thanks to Cisco Systems

78. 78 What is a Router A layer 3 device – –Works at physical, data link and network layers e.g. Internet Protocol (IP) level –Is a bridge between a number of distinct networks Example your internal network and the internet beyond Range from simple devices ADSL router for home users –To Extremely complex enterprise level Looks at the destination of each IP packet and determines where it would be sent on for its next hop –Tries to select the best route

79. 79 Other Devices Hubs –A central device that acts like a multiport repeater –Date mainly from the time of non switched ethernet Brouters –A single or multiprotocol router that sometimes acts as a bridge and sometimes as a router

80. 80 Connecting Devices and the OSI Model

81. 81 ADSL – Modem for the 21 st Century Normal telephone lines support only a subset of the frequencies found in human speech –This limits the available bandwidth –ADSL uses part of this untapped bandwidth –Download bandwidth typically greater than upload, hence the A for Asynchronous Suits the needs of the consumer market Business users may wish to get equal –Quite vulnerable to noise Limits on your distance from exchange –Further away the slower the available speed Combined with VPN a true work from home solution

82. 82 Transmission Media Transmission Media Characteristics –Bandwidth –Response Time for a request Transmission Media Types –Twisted Pair –Coaxial cable- –Fiber Optics –Wireless Media – Radio, Microwaves, Infrared, Lightwave

83. 83 Twisted Pair The wire consists of two insulated copper wires about a mm thick, normally 24 gauge solid core copper. The purpose of twisting the wires is to reduce electrical interference. (two parallel wires would act as an antenna). Various categories of cable Many twisted pair cables can be bundled together, typically 4 pairs They can be used for analog and digital transmission. The bandwidth depends on the thickness of the wire and the distance travelled. Shielded Twisted Pair (STP) and Unshielded Twisted Pair(UTP)

84. 84 Twisted-Pair Cable

85. 85 Effect of Noise on Parallel Lines  The McGraw-Hill Companies, Inc., 1998

86. 86 Noise on Twisted-Pair Lines  The McGraw-Hill Companies, Inc., 1998

87. 87 Unshielded Twisted-Pair Cable (UTP) Most common type of cable used in computer networks 8 wires forming 4 pairs Different qualities –Cat 3 – for 10Mbps –Cat 5 - for 100Mbps –Cat 5e – for 1Gbps Most common in current use –Cat 6 – better for 1Gbps may allow 10Gbps Best to future proof to avoid pain later Cables of different types look identical –Cable type is printed on the side

88. 88 Shielded Twisted-Pair Cable  The McGraw-Hill Companies, Inc., 1998

89. 89 Fiber Optics An optical transmission system has three components –The light source –The transmission medium –The detector. A pulse of light indicates a 1, lack of light indicates a 0. The transmission medium is a unidirectional ultra thin fibre of glass or plastic The aim is to get the angle of incidence of the light at such a point to make the light refract back into the medium. In the case of a fibre optic cable this means the light is trapped within the cable. At the centre of the cable is the glass/plastic core which is surrounded by a glass cladding and then a plastic coating.

90. 90 Transmission Media Performance MediumCostSpeedAttenuationEMISecurity UTPLow1-100MbpsHigh Low STPModerate1Mbps-1GbpsHighModerateLow CoaxModerate1Mbps-1GbpsModerate Low Optical Fibre High10Mbps-10GbpsLow High RadioModerate1-54MbpsLow-HighHighLow MicrowaveHigh1Mbps- 10GbpsVariableHighModerate SatelliteHigh1Mbps- 10GbpsVariableHighModerate CellularHigh9.6-19.2KbpsLowModerateLow

91. 91 Example Sizes of Medical Images

92. 92 Network Users –Developers –Administration staff (software and hardware) –End users (specialised users, general public) Uses of Networks –Resource Sharing- locally or over considerable distance. –High Reliability- multiple CPUs, replication of files. –Saving money- Price of PCs compared to mainframes.

93. 93 Scalable solutions- The network can grow as the needs do Communication medium- supporting team work Accessing remote information- banking, health issues, hobbies, shopping Person to person communication- e-mail, instant messaging, video conference Interactive entertainment- films, games, live shows.

94. 94 Uses of Networks in Healthcare? Communicating into/out of and between hospitals Paging Staff Networking instrumentation Maintenance of instrumentation To aid communication –Professional to professional. –Professional to patient. –Patient to patient. Sharing Information of all types

95. 95 Network and Distributed Systems There is some confusion over these two terms. –Hardware is required for both to operate The distinction is in the software. –In a distributed system the existence of the autonomous computers is transparent. –The system is concerned with doing a job and not with how the connections are established and managed. A distributed system refers to software built on top of a network. With a network the user needs to explicitly deal with the network in terms of logging on, deciding which computer to use and managing the network.

96. 96 Section 6 - Security Security Issues Virtual Private Networks Issues with wireless networks Methods of attack Risks

97. 97 Security Issues Secrecy –Keeping information out of the hands of unauthorised users. Authentication –Making sure you are talking to the right person. Data Integrity control –Making sure the data is correct. Security effects each layer in the network design.

98. 98 No Network Is Secure Original Ethernet –Every host on the bus could see and capture every transmission made Trivial to recover passwords, web pages you viewed The physical network itself cannot be considered to be secure –Wires can be tapped Wireless communications available to all within range with a suitable receiver Need to trade off the strength of security with the practicality of the measures –Users when faced with a complex process may attempt to undermine the system Sharing of passwords or not logging out

99. 99 Wireless Networks Extremely vulnerable to attack –Anyone with a suitable radio can listen IEEE 802.11 originally used a 40 bit WEP key –Shared encryption key by all users of the network –Later versions supported a 104 bit key –Proved to be very easy to crack in both versions WiFi Protected Access (WPA/WPA2) –Based on 802.11i standard –EAP extensible Authentication Protocol »Authentication framework not a protocol »Can integrate with existing authentication systems »802.1x

100. 100 Best practice in Network Management is to heavily restrict access to external users or to block it totally –Avoid potential security issues –Protect from hackers What of legitimate users –People who work at other locations –Particularly relevant concerns in the Healthcare Domain

101. 101 VPN – Virtual Private Network Not strictly a security solution Two implementations –Connecting you to a remote network –A network within a network Allows you to access resources on another network as if you where connected directly A secure encrypted tunnel between your computer and others on the same network Typically requires a dedicated ‘VPN box’ on the office end network to provide the service

102. 102 VPN - Connecting you to a remote network Ideal for a single user –Work from home, on the road, other institution User needs VPN client software –Setup can be complex for users –Need to implicitly log in to access the network Not transparent –Potential security risk if users computer is breeched Hacker may have access into network

103. 103 Methods of Attack (1/3) Impersonation –Using someone else’s password or a terminal that is already logged on. Active wire-tapping –Connecting a device(authorised/unauthorised) to a communication link to obtain access to data through the generation of false messages. Passive wire-tapping –Monitoring data coming over a communication link. Traffic flow analysis –Analysing the frequency of data traffic, seeing which data is encrypted and which is not. Eavesdropping –interception of information

104. 104 Methods of Attack (2/3) Replay –Play back a recording of a communication Routing Table modification –Sending messages to the wrong address or multiple addresses. Audit Trail Information Modification –To cover up an attack. Operational Staff Table Modification –To change access rights. Bogus Frame insert –Inserting bogus information as a frame. Data Portion Modification –Modify the data portion of a message. Viruses

105. 105 Methods of Attack (3/3) Sequencing Information Modification –Change the order of the pieces of information. Message Deletion –Removing the message completely Protocol Control Information modification –To send data to a different location. Misuse of resources –Swamping communication lines – Denial of service Interruption of power supply –Denial of service Malicious physical damage –Denial of service Theft –Parts of computers or entire computers could be stolen. Confidentiality issues arise.

106. 106 Disposal of computer hardware You typically contract a third party to securely shred paperwork, but you skip a used computer. –Computer can store a virtually unlimited amount of data in a easy to search format Serious privacy issues concerning medical records Computer may have no confidential information but! –Usernames, passwords, security certificates and so on for networked information may be stored on the computer, thus allowing access Essential the contents of the hard disk be wiped not just deleted –Most operating systems have the ability to do this –Or remove hard drive and use a sledgehammer

107. 107 Section 6 - The Internet and the World Wide Web Addressing and Domain Names Who is in charge Relationship between IP address and hostnames Arrangements for.ie domains

108. 108 Internet Addressing and Domain Names To be able to identify a host on the internetwork, each host is assigned an address –Internet Protocol address. Addresses are assigned in a delegated manner. The Internet Corporation for Assigned Names and Numbers (ICANN) has responsibility for Internet Protocol (IP) address space allocation What is ICANN? As a private-public partnership, ICANN is dedicated to –preserving the operational stability of the Internet; –to promoting competition; –to achieving broad representation of global Internet communities –to developing policy appropriate to its mission through bottom-up, consensus-based processes.

109. 109 Internet Addressing and Domain Names ICANN are the top body. They comprise IANA http://www.iana.org/ Users are assigned IP addresses by Internet service providers (ISPs). ISPs obtain allocations of IP addresses from a local Internet registry (LIR) or national Internet registry (NIR), or from their appropriate Regional Internet Registry (RIR): APNIC (Asia Pacific Network Information Centre) - Asia/Pacific Region ARIN (American Registry for Internet Numbers) - North America and Sub-Sahara Africa LACNIC (Regional Latin-American and Caribbean IP Address Registry) – Latin America and some Caribbean Islands RIPE NCC (Réseaux IP Européens) - Europe, the Middle East, Central Asia, and African countries located north of the equator

110. 110 Internet Addressing and Domain Names The.org domain is operated by Public Interest Registry. It is intended to serve the noncommercial community, but all are eligible to register within.org. The.com domain is intended to serve the commercial community. The.gov domain is reserved exclusively for the United States Government. It is operated by the US General Services Administration. The.edu domain is reserved for postsecondary institutions accredited by an agency on the U.S. Department of Education's list of Nationally Recognized Accrediting Agencies and is registered only through Educause. The.net domain is reserved for networks; usually reserved for organizations such as Internet service providers

111. 111 IP and Internet Addressing Currently there are two types of Internet Protocol (IP) addresses in active use: –IP version 4 (IPv4) and IP version 6 (IPv6). IPv4 was initially deployed on 1 January 1983 and is still the most commonly used version. IPv4 addresses are 32-bit numbers often expressed as 4 octets in "dotted decimal" notation (for example, 192.0.32.67). Can cater for 4.4 billion addresses Deployment of the IPv6 protocol began in 1999. IPv6 addresses are 128-bit numbers and are conventionally expressed using hexadecimal strings (for example, 1080:0:0:0:8:800:200C:417A).

112. 112 IP Addresses 32-bit number in IPv4 –4,294,967,296 addresses IP addresses are unique and universal –with some exceptions Dotted decimal notation: –Bytes of binary notation represented as decimal separated by dot Internet hosts have both IP addresses and hostnames –wilde.cs.tcd.ie == 134.226.32.55

113. 113 Sending IP datagrams over Ethernet When the network layer wishes to send data across the data link layer IP address needs to be mapped to an ethernet address Ethernet card IP Implement. Card driver AA.BB.CC.00.00.11 172.16.1.1

114. 114 Mapping Domain Names –Hostname - wilde.cs.tcd.ie –Internet Address - 134.226.32.55 How does a machine translate a fully qualified hostname into an IP address? It consults its nearest Domain Name Server (DNS) The local Nameserver knows the mappings for local machines and –At least one root nameserver which knows all nameservers for the top level domains.

115. 115.ie domains All registrations handled by the IE Domain Registry - www.iedr.ie –Was based in UCD until 2000, now a independent non profit making body –You are required to prove a connection to the domain name sought 10 th Feb 2008 –Total number of domains 118,515 In Jan 1995 –Total domains 347

116. 116 Growth in.ie domains

117. 117 Section 7 – Telemedicine What is it?

118. 118 Definitions Telemedicine is the rapid access to shared and remote medical expertise by means of telecommunications and information technologies, no matter where the patient or the relevant information is located. (CEC 1993) Telemedicine has been defined in General Terms as “Medicine practiced at a distance” and as such, it encompasses both diagnosis and treatment, as well as medical education. (Journal of Telemedicine and Telecare, 1995)

119. 119 Definitions Telemedicine is the delivery of healthcare services, where distance is a critical factor, by all healthcare professionals using information and communications technologies for the exchange of valid information for diagnosis, treatment and prevention of disease and injuries, research and evaluation, and for the continuing education of healthcare providers, all in the interests of advancing the health of individuals and their communities. (World Health Organisation 1998)

120. 120 Telemedicine Many different definitions of Telemedicine. Be aware of this. Telemedicine is a process not a technology. Can be applied to many different domains. Can be used for patient/clinician, patient/patient, clinician/clinician communication. Can be used to support training As with all applications of technology, appropriateness is the key. The application should be clinically driven.

121. 121 Definition The WHO offers a holistic definition of telemedicine: “The delivery of healthcare services, where distance is a critical factor, by all healthcare professionals using information and communication technologies for the exchange of valid information for diagnosis, treatment and prevention of disease and injuries, research and evaluation, and for the continuing education of healthcare providers, all in the interests of advancing the health of individuals and their communities” (WHO 2004) Telecare, a term often associated with telemedicine, can be defined as: "...the use of information and communication systems to give patients with or without their healthcare professional or informal carer access to information sources wherever they are located… frequently…within patients' place of residence” NHS (2004)

122. 122 Characteristics of Telemedicine systems Interaction style- Real Time, Store and Forward. Data types- Text, Images, Sound, Video Equipment Action – Direct Intervention, Advice Patient numbers – one patient, multiple patients Duration

123. 123 Some Advantages and Obstacles of Telemedicine Advantages –Improved use of resources –Continuing professional development –Reduces unnecessary patient transfers –Facilitates homecare for the elderly and the chronically ill –Equitable access to care! –Links doctors with remote centres of excellence –Wireless links can be used in cases of lack of infrastructure Obstacles –Patient and professional dissatisfaction in some specialities –Lack of standards –Security issues –Legal and ethical implications –Equipment failure –Lack of protocols of care for these new types of interactions.

124. 124 History Pre-electronic telemedicine –Accounts from the middle ages of a physician examining a patient for plague- the patient and the physician were on opposite sides of the river. –Prescribing by post was practised well before national postal systems were in place. Electronic telemedicine –Telegraphy- equipment was developed to send an X-ray –Telephony- voice communication, computer networks –Radio- initially by morse code and later by voice. –Television- closed circuit television, video conferencing –Wireless communication- use of mobile phone technologies and satellites.

125. 125 Research Why is Telemedicine not in widespread use? The technologies exist but the organisational and personal problems exist. Lots of funding has been allocated and has been spent on projects analysing, testing and evaluating technical requirements. More projects/research should be funded to show cost-effectiveness and evaluation of new Telemedicine applications.

126. 126 Ethical and Legal Issues Some projects in Europe have looked at certain aspects of this area (SEISMED, ISHTAR, TrustHealth and SIREN). They have mainly been concerned with the security and confidentiality. More work needs to be done to research other aspects including accountability, responsibility, licensure, reimbursement, intellectual property rights, changes in consultation and referral patterns, defining the ‘owner of patients’, defining geographical catchment areas.

127. 127 Economics/Evaluation Need to compare the new technology with an alternative way of working. What is the system costing at the moment? How to asses the cost of the new technology- equipment, software, installation, training, maintenance, legal, utilisation rates. How do we asses the benefits- people getting well, shorter stays in hospital, less time spent with the expert, patient not having to travel, expertise experienced by the remote healthcare professional. Methods are required if economic evaluation is to take place. Care should be taken when comparing costs across, domains, environments and time.

128. 128 Practice Teleradiology Telepathology Teledermatology Telecardiology Telepsychiatry Teleorthopaedics Surgical Consultations TeleENT Tele-EEG Minor Injuries Mobile Telemedicine Maritime Telemedicine Teleopthamology Home Care Telephone Services Education Telesurgery

129. 129 Using Networks to Provide Equality of Care? Network Infrastructures- Network hardware and network software Network users Software applications Legislation Standards Delivering care (need experts on site)

130. 130 Network Infrastructure In order to avail of networked healthcare a network infrastructure must be in place. This infrastructure requires an initial investment, maintenance investment and investment to keep it up to date It is hard to see therefore even at the technology end how equality of care can be achieved.

131. 131 Network Users In various countries, regions and hospitals different levels of technical skill exist. If we assume that all places have the same network infrastructure it still doesn’t allow us achieve equality of care

132. 132 Software applications On top of the network infrastructure software applications. Depending on economics, skill and awareness of users differences can exist. Not everyone will be aware of the software applications that exist and the implications of choosing particular software e.g. from standards point of view

133. 133 Legislation Be aware that using networks allows the user to bypass physical boundaries thus enabling a specialist in Ireland to communicate with a patient in England. There are legal implications to this that haven’t been addressed. Equality of care may not be possible due to these legalities. The closer you live to the specialist the better.

134. 134 Standards In order to have healthcare delivered to all areas standards are required. Communication standards Coding standards e.g. for diagnosing, prescribing. Data set format standards Semantic standards If all areas do not agree to the standards then equality of care is not possible.

135. 135 Experts on site Even if all the infrastructure, software applications, standards, legislation and skills are equal is it possible to get equality of care? Remember healthcare is ultimately delivered by human experts. Technology can only be used to support the current processes of healthcare delivery or to make new processes possible.

136. 136 TIE Telemedicine Information Exchange (US) http://tie.telemed.org/ Covers: –Extensive bibliography (>14,000 entries) –Projects –Events calendar –Funding sources –News