Building the Mobile Internet

1. Building the Mobile Internet March 2012 Youn-Hee Han LINK@KoreaTech http://link.koreatech.ac.kr

2. Chapter 1. Introduction to “Mobility” LINK@KoreaTech 2

3. Prolog…  The ability to access any content, on any device over any network in any location, is becoming a reality.  Mobility – is a truly pervasive quality associated with nearly all advances in Information and Communications Technology (ICT) – has not been integrated into the fabric of the Internet • instead, a range of different techniques are available for delivering such a mobile experience. – supports… • a user with a laptop who wants Internet access everywhere he goes • a user with a mobile device who wants a seamless Internet experience while he is moving • a user wanting to use unlicensed Wi-Fi technology to offload traffic from a conventional cellular network • a user who has multiple devices and wants a seamless Internet experience across those devices LINK@KoreaTech 3

4. Prolog…  As today’s networks migrate toward “all-IP,” numerous protocols and solutions have been designed to handle these different types of mobility, with varying degrees of market adoption and formal standardization.  This book… – looks at the protocols that are relevant to the mobility landscape, – contrasts different approaches at delivering the mobile experience, – accurately defines and discusses the mobile Internet evolution. LINK@KoreaTech 4

5. Mobility Market  Cellular Service History – Simple circuit-switched service voice • Global System for Mobile (GSM) communications • Code Division Multiple Access (CDMA) standard • Short Message Service (SMS) – Initial adoption of IP-based packet services • low-rate General Packet Radio Service (GPRS) • cdma2000 1xRTT-based radio access networks – Increasing uptake of mobile broadband services • High Speed Packet Access (HSPA) • EVolution-Data Only (EV-DO) • Worldwide Interoperability for Microwave Access (WiMAX) • Long-Term Evolution (LTE) radio access networks. LINK@KoreaTech 5

6. Mobility Market  Recent Trend I - Internet being dominated by mobile hosts LINK@KoreaTech 6

7. Mobility Market  Recent Trend II - Rise of multi-radio devices – Multi-interfaced devices – 3GPP has defined a triple-mode cellular architecture that allows a single radio to be shared among… • second-generation GPRS • third-generation HSPA • next-generation LTE radio access modes. • [restrictions] these devices can only be connected to one network at any instant – By 2015, ABI Research estimates that one in three handsets shipped globally will include Wi-Fi–enabled dual-mode capability 3GPP (Third Generation Partnership Project (http://www.3gpp.org)) - a collaboration among Organizations (SDO) that is responsible for developing the set of technical specifications for 3G systems based on the evolved GSM core network. various Standards Development LINK@KoreaTech 7

8. Mobility Market  Recent Trend III - Rise of multiple handsets per subscriber (1/2) – In 2007, the Organization for Economic Co-operation and Development (OECD) reported that… • over 25 countries had cellular penetration rates in excess of 100 percent, with Italy taking the lead in reaching 150 cellular subscriptions per 100 inhabitants – In 2009, Cisco Internet Business Solutions Group (IBSG) estimated that… • in 2010, 35 billion devices will be connected to the Internet  equivalent to nearly six devices per person on the planet. • many of these new devices will be used to provide machine-to-machine (M2M) services,  while many M2M devices are not strictly mobile (an M2M-enabled residential utility meter is unlikely to move), it is likely that a significant proportion of these new devices will use wireless connectivity to provide access to M2M services. LINK@KoreaTech 8

9. Mobility Market  Recent Trend III - Rise of multiple handsets per subscriber (2/2) – Reinforcing this shift from “architectures that assume a single device per user” to “one where each subscriber has a multitude of devices” is the current revolution in tablet-style computers. – Forrester Research has recently highlighted… • Desktop PCs  gaming, watching and editing high-definition and three-dimensional video and graphics. • Tablets:  media consumption, email and web browser–based services. • Netbooks:  web-centric operating systems, the associated cloud-based applications and storage. – The networks used to support such devices are set to increasingly converge • This convergence is being driven by the increasing adoption of IP as the convergent technology across “fixed” and “mobile” networks • IP = the fundamental building block for all next-generation communication networks LINK@KoreaTech 9

10. Mobility Market  Cellular Network Evolving to All-IP Network – the various definitions for the next generation of mobile networks all align around an “all-IP” vision, providing purely packet-switched capabilities and solely supporting IP services. – As cellular networks transition to “all-IP” networks, the architectures of fixed and cellular networks converge Customer Premises Equipment (CPE) Digital Subscriber Line Access Multiplexer (DSLAM) (BNG): the user’s IP Point of Attachment (PoA) to the Internet Enhanced Node B (ENB) base station : licensed cellular technology User Equipment (UE) Packet Data Network Gateway (PGW) : IP PoA for the mobile subscriber Serving Gateway (SGW) : Layer 2 tunnel switch LINK@KoreaTech 10

11. Consumption Trends  In 2009, Cisco IBSG announced the change on Average Revenue Per User (ARPU) LINK@KoreaTech 11

12. Consumption Trends  “Connected Life Market Watch” reports on where mobile Internet consumption occurred – Occasional mobile Internet users were more likely to access services when mobile – Regular users of mobile Internet–based services were more likely to consume the majority of mobile Internet services from fixed locations Necessity of Home ENB LINK@KoreaTech 12

13. Consumption Trends  Huge volume of mobile data – CISCO Visual Network Index (VNI) forecast predicts that… • mobile data in 2014 will be 39 times larger than the mobile data traffic in 2009 • by the end of 2014, video is forecast to comprise 66 percent of all mobile data traffic, and mobile voice traffic will comprise only 4 percent of the overall total traffic LINK@KoreaTech 13

14. Consumption Trends  when users access mobile Internet services – the data-busy hour is between 8:00 and 9:00 in the evening LINK@KoreaTech 14

15. Consumption Trends  The final characteristic of future mobile consumption will be its “always-on” nature. – Lagacy cellular standards allowed mobile data–enabled devices to be attached to a cellular network without allocating them an IP address. • automatically deallocate a device’s IP address after a period of inactivity – On the other hand, wireless LAN networks has been based on the assumption of an always-on Ethernet service – The next generation of cellular standards (all-IP LTE network) has been designed to support only always-on behavior LINK@KoreaTech 15

16. Mobile Challenges  Three key cellular characteristics on the “capacity” – Radio Frequency Spectrum • A very scarce resource. • It must be available in sufficient bandwidths to support higher-speed access while also providing good propagation characteristics required for providing wide-area coverage. – Spectral efficiency • There is an upper bound (Shannon Limit ) to the amount of information that can be transferred in a given bandwidth which is subject to background noise • More advanced signal-processing techniques are rapidly approaching such a theoretical limit. – Frequency reuse • Because of its relative scarcity, mobile systems are required to reuse their allocated radio spectrum across a particular network of cell sites. • Increasing the capacity by frequency reuse typically means dividing an existing cell into multiple smaller cells. LINK@KoreaTech 16

17. Mobile Challenges  Increase rate of Average Macro-Cellular System Capacity does not follow the demand for mobile Internet traffic – Cisco VNI forecast estimates that demand for mobile Internet traffic will grow 39-fold over a five-year period – Figure 1.9 shows that the mobile broadband capacity increases by a factor of 4-fold over the same five-year period – The only way to support the demand is the adoption of smaller cells LINK@KoreaTech 17

18. Mobile Challenges  Building the future mobile Internet will require networking technology that supports the following: – Scalable adoption of small-cell technologies—for example, using unlicensed IEEE 802.11 technology or licensed cellular-based home base station solutions – A massive number of always-on devices, including scenarios where single subscribers have access to multiple devices – Ubiquitous access, including nomadic access from in buildings as well as wide-area mobile access for on-the-go consumption – Seamless access to a range of mobile services, including video, web access, peer-topeer, Voice over IP (VoIP), and gaming services LINK@KoreaTech 18

19. Mobile Challenges All this complexity is caused because, when IP was first proposed in 1975, “problems of. . . mobility were many years off.”  Current Internet is not mobile!!!  Conventional approaches for delivering mobility have been to layer tunnels on top of the native Internet Protocol (IP). – GPRS Tunneling Protocol (GTP) • An overlay IP-based mobility protocol defined by 3GPP to provide mobility services for accessing the Internet by GPRS, WCDMA, and LTE. – Mobile IP (MIP) • An overlay mobility protocol defined by the Internet Engineering Task Force (IETF) to provide IP mobility services and adopted by 3GPP2 to provide mobility services for accessing the Internet by cdma2000. – Control and Provisioning of Access Points (CAPWAP) • An overlay IP-based mobility protocol defined by the IETF to provide mobility services for accessing the Internet by IEEE 802.11–based radio access networks. – Proxy Mobile IP (PMIP) • An overlay IP-based mobility protocol defined by the IETF to provide mobility services that have been adopted by IEEE 802.16e–based WiMAX. LINK@KoreaTech 19

20. Mobile Challenges  The industry will soon be faced with the situation that the default technique for accessing the Internet will be through a mobility tunnel  Because tunneling of traffic requires stateful tunnel gateways to be operated, services accessed through the “mobile Internet” might end up being more brittle than those accessed through the native IP networks LINK@KoreaTech 20

21. Chapter 2. Internet “Sessions” LINK@KoreaTech 21

22. Prolog…  Hard to enable seamless and real-time mobility while keeping “communication session” regardless of its location – Someone wants to keep talking without losing your connection to the person on the other end of the line. – The problem becomes even harder at the case of “Vertical Handover” • when moving across different types of access networks • when moving across networks belonging to different operators. Home Agent Public Internet Access Router IPv6 (or v4) Core Network Wireless Router 3G/4G Cellular 802.11/Hotspot 802.16e/Wibro LINK@KoreaTech 22

23. Prolog…  This so-called “session mobility” is one of the more challenging issues in enabling the mobile Internet  This chapter provides… – a high-level overview of the way the Internet works – explains where the difficulties lie in making session mobility possible. LINK@KoreaTech 23

24. Internet and Communication  Internet – Networks • use many different hardware technologies – Hosts • want to communicate with each other by using the TCP/IP protocol suite • many different applications run on hosts – Routers • connected to more than one network and forward data from one network to the other LINK@KoreaTech 24

25. Packet Switching Versus Circuit Switching  Circuit switching – Traditional telephone networks – for a given communication, a dedicated circuit is created between the two endpoints of a communication session – pros • dedicated resources: no sharing  guaranteed performance – cons • when the circuit is not used (that is, for example, when both parties are silent in a phone conversation), the capacity of the circuit is wasted • Set up (connection) times is needed E F A D B C * 접속중인 두 지점 사이에는 물리적인 연결이 지속된다. * 접속중인 두 지점 사이에는 물리적인 연결이 지속된다. LINK@KoreaTech 25

26. Packet Switching Versus Circuit Switching  Packet switching – Internet (TCP/IP) – The data of a communication session is divided into “packets” – Each packet contains information to enable the network to decide how to send it to the receiving end. – All packets are being sent independently to the receiver – Receiver reassembles the packets to reconstruct the original data. LINK@KoreaTech 26

27. Packet Switching Versus Circuit Switching  Packet switching – Pros • Multiplexing - the same network communication path can be used for multiple communication sessions – Cons • Packets may be received out of order • Delivery of the packets is “best effort.”  Not guaranteed delivery  Some communications might use all the available resources,  Some packets might be dropped or delayed  Some connection can fail completely.  Who is winner? Circuit switching vs. Packet switching – All modern networks use packet-switching technology – It is often easier and cheaper to increase (wired) capacity – with the exception of some mobile networks that have limited capacity because of physical limitations of the wireless spectrum. LINK@KoreaTech 27

28. Packet Switching Versus Circuit Switching  Packet switching [추가 자료] – Two schemes: Datagram vs. Virtual Circuits – Datagram • 패킷마다 주소를 넣어 구성 - 패킷을 독립적으로 취급 (라우팅) • 송신지의 패킷 순서와 수신지의 패킷 순서가 다를 수 있음 • 호 설정 절차가 필요없음 • 망 운용에 높은 유연성 제공 – Virtual Circuits • 전송 시작전에 두 지점 사이에 논리적 전송로 설정 • 주소 보다 논리적 “전송로 번호”를 설정하여 패킷에 명기 • 라우팅과 관련된 결정을 할 필요 없음  각 라우터가 패킷에 대한 경로를 이미 알고 있음 • 패킷의 순서 및 오류 제어를 망에서 제공 • 패킷을 신속하게 전송 LINK@KoreaTech 28

29. Packet Switching Versus Circuit Switching  Packet switching [추가 자료] – Two schemes: Datagram vs. Virtual Circuits LINK@KoreaTech 29

30. Packet Switching Versus Circuit Switching  Circuit-Switching vs. Virtual Circuits vs. Datagram [추가 자료] Transmission delay LINK@KoreaTech 30

31. IP over Everything, Everything over IP  IP: The pivot point of TCP/IP-based communications – IP shields… • the underlying network technology from the applications  when a new data-link transport technology is developed, IP will allow all existing applications to be used  [NOTE] let’s google with keyword 'RFC "IP over *"' • the applications from the underlying network technology  when an application uses IP packets for communication, it will automatically work on all IP networks. – Instead of having to wait for an operator to make a certain service available to the users, every clever student can now develop his own application. LINK@KoreaTech 31

32. Addresses  IP Address – Internet communication is about sending IP packets from a source IP address to a destination IP address – IP address is both used to identify the host itself as well as its location in the network • if a host is at the same time connected to two networks, it will also have at least two IP addresses, one for each of its network interfaces. • if a host that is attached to one network moves to another network, it must change its IP address.  Routers… – use the destination IP address to determine how to forward the IP packets from the source to the destination  The receiver… – copies the source IP address from a received packet into the destination address to send any return packets. LINK@KoreaTech 32

33. Addresses  IPv4 Address (RFC 791) – 32-bit binary numbers • the binary representation 00001010 00000000 00000000 00000001 is written in decimal representation as 10.0.0.1. – composed of two parts • a network identifier (net-id) • a host identifier (host-id) – The net-id is the same for all hosts on a particular network.  Classful addressing (used in the early days of the Internet) – the boundary between the network and the host part of the IP address was at fixed 8-bit positions – Cons • If an organization has, for example, 300 hosts, the IP address registry would have to assign it a Class B network that can be used to address over 65,000 hosts, a large waste of usable addresses. LINK@KoreaTech 33

34. Addresses  Classful addressing [보조 자료] 0~127 128~191 192~223 224~239 240~255 LINK@KoreaTech 34

35. Addresses  Classful addressing [보조 자료] Class A addresses are wasted!!! LINK@KoreaTech 35

36. Addresses  Classful addressing [보조 자료] Many class B addresses are wasted too. LINK@KoreaTech 36

37. Addresses  Classful addressing [보조 자료] Class C blocks are too small for most businesses. LINK@KoreaTech 37

38. Addresses  Classless interdomain routing (CIDR) (RFC 1518) – allow a split between net-id and host-id at an arbitrary bit position – network mask • indicates how many bits of the IP address (the so-called prefix) are used to indicate the net-id and how many belong to the host-id (the suffix). Network prefix • Used by every hosts/routers to determine which part of IP address is to be used for the “prefix (=subnet address)” 255.255.255.128  /25 255.255.255.192  /26 . . . 255.255.255.254  /31 In the organization with 300 hosts… - Prefix length: 23 - Suffix length: 9  512 addresses LINK@KoreaTech 38

39. Addresses  Aggregation and Subnetting – “141.14.0.0/16” network can have 216hosts. – Assume that there is only 1 network with a whole hosts! – Problems? LINK@KoreaTech 39

40. Addresses  Aggregation and Subnetting – What if we break the network into 4 subnets? LINK@KoreaTech 40

41. Addresses  Aggregation and Subnetting – KoreaTech Subnetting KoreaTech is allocated the network address “220.68.64.0/19”  Allocate its address block into each sub group 220 68 ISP's block 11011100 1000100 01000000 00000000 220.68.64.0/19 Organization 1 11011100 1000100 01000000 00000000 220.68.64.0/24 Organization 2 11011100 1000100 01000001 00000000 220.68.65.0/24 Organization 3 11011100 1000100 01000010 00000000 220.68.66.0/24 ... ….. …. …. Organization 32 11011100 1000100 01011111 00000000 220.68.95.0/24 LINK@KoreaTech 41

42. Addresses  Aggregation and Subnetting Organization 0 200.23.16.0/23 Organization 1 “Send me anything with addresses beginning 200.23.16.0/20” 200.23.18.0/23 Organization 2 ... 200.23.20.0/23 Fly-By-Night-ISP ... Internet Organization 7 200.23.30.0/23 “Send me anything with addresses beginning 199.31.0.0/16” ISPs-R-Us LINK@KoreaTech 42

43. Addresses  Aggregation and Subnetting – In real-world, aggregation is not effective Organization 0 200.23.16.0/23 Organization 1 “Send me anything with addresses beginning 200.23.16.0/20” 200.23.18.0/23 Organization 2 ... 200.23.20.0/23 Fly-By-Night-ISP ... Internet Organization 7 200.23.30.0/23 “Send me anything with addresses beginning 199.31.0.0/16 or 200.23.18.0/23” ISPs-R-Us LINK@KoreaTech 43

44. Addresses  Q: How does an ISP get block of addresses?  A: ICANN(Internet Corporation for Assigned Names and Numbers) – allocates addresses – manages DNS – assigns domain names, resolves disputes LINK@KoreaTech 44

45. Addresses  ICANN 산하 IANA (Internet Assigned Numbers Authority) – 인터넷 할당 번호 관리기관  RIR (Regional Internet Registry) – 대륙별 인터넷 레지스트리 – APNIC (Asia Pacific Network Information Center) • 아시아· 태평양 지역 – RIPE-NCC (Réseaux IP Européens Network Co-ordination Centre) • 유럽 – ARIN (American Registry for Internet Number) • 북남미 외 기타 지역  국가별 NIC (Network Information Center) – 한국은 KISA(한국인터넷진흥원) 안에 있는 KRNIC(한국인터넷정보센터) 에서 담당 – https://ip.kisa.or.kr/main.html LINK@KoreaTech 45

46. Addresses  ICANN 산하 IANA (Internet Assigned Numbers Authority) – 인터넷 할당 번호 관리기관 LINK@KoreaTech 46

47. Addresses  IPv4 vs. IPv6 (RFC 2460) LINK@KoreaTech 47

48. Routing  Routing – the process of 1) discovering how to forward the packets from sender to receiver, and 2) forwarding packets from one network to the other.  Routers – have multiple network interfaces that are connected to more than one network at the same time – have knowledge about networks that can be reached through a particular interface. • Forwarding table  used to look up over which interface they should send a packet for a particular IP address. • Through the use of routing protocols, routers can make up its forwarding table. – can forward packets from one network to the other. LINK@KoreaTech 48

49. Routing  In routers… routing protocols local forwarding table destination output link 0100 0101 0111 1001 3 2 2 1 value in arriving packet’s header 1 0111 2 3 LINK@KoreaTech 49

50. Routing  Routing Protocols – routers tell neighbor routers “which networks are reachable through them.” – Two categories • Interior gateway protocols (IGP)  the protocols used inside an administrative domain.  focus on routing IP packets as efficiently as possible.  Examples » Open Shortest Path First (OSPF) » Routing Information Protocol (RIP) » Intermediate System–to–Intermediate System (IS-IS). • Exterior gateway protocols (EGP)  the protocols that are used between administrative domains.  Efficiency is not the only criterion.  policy-based routing » Business relations, reputation, and past experience determine which route is preferred or is not allowed  The dominant EGP is Border Gateway Protocol (BGP) (RFC 4271). LINK@KoreaTech 50