林振緯

1. 網際網路之沿革與趨勢 林振緯 Department of Computer Science & Information Engineering, Fun Jen Catholic University, Taipei, Taiwan jwlin@csie.fju.edu.tw Nov. 12, 2004

2. Outline • Introduction • Wireless LAN • GSM • GPRS • 3G • Mobile IP

3. Networks Today Core Networks The WWW IP based Internet LAN Modem, ADSL PSTN Network Wireless Network MPLS Network ATM Network Other Services Wireless Video Server (By Dr. Zheng da Wu)

4. Wireless Internet • New area • Diverse mobile devices • Wireless communication networks • Internet • Users can access various services, any time and any where

5. Wireless LANs and WANs 100 m 2,500 m LAN WAN

6. Wireless LAN • Replace the wired Ethernet LANs in a local area • Provide access to wired LANs and the Internet • Offer high data rates • Currently, up to 54 Mbps

7. Major Standards for WLAN • HIPERLAN • High Performance Radio LAN • European standard • IEEE 802.11 • US standard • Today, it holds the entire market

8. Two Modes of IEEE 802.11 • Infrastructure Mode • Terminals communicate to an access point. • Ad Hoc Mode • Terminals communicate in a peer-to-peer basis without any access point.

9. 802.11 - Infrastructure Mode IEEE 802.11 LAN BSS-2 BSS-1 AP AP Basic Service Set (BSS) – the stations and AP within the same radio coverage. Database for location management andRoaming Distribution System Portal Internet Internetworking Wired IEEE 802.x LAN

10. 802.11 – Ad Hoc mode Internet Mobile Ad-hoc Networks(MANET) • Ad-hoc On-demand Distance Vector (AODV) • Dynamic Source Routing (DSR)

11. Access Point (AP) • A layer 2 bridge between IEEE 802.11 and Ethernet • A switched Ethernet subnet attached to the layer 2 distributed network • A finite range, on the order of 500 feet indoor and 1000 feet outdoors

12. Other WLAN APs User DB L2 distribution network AAA roaming Access Router AAA Server/Proxy IP backbone network WLAN terminals L2 distribution networks AP Billing System Local Service HTTP server Access Router WLAN terminals AP Gateway Interface to external IP networks (Internet) DNS DHCP WLAN Radio interface WLAN, IP and Internet IP interface

13. Global System for Mobile Communications (GSM) • Frequency Band • 890 – 915, 935-960 MHz • Channel spacing: 200 KHz • Total channel number: 124 • Number of slots per channel: 8 • Multiple Access • TDMA and FDMA • Data services up to 9.6 kbps

14. Architecture of GSM Base Station SubSystem Base Transceiver Station (BTS) cellular telephone system Base Station Controller (BSC) Network SubSystem Mobile station (MS) with smart card, Subscriber Identity Module (SIM) Mobile Service Switching Center (MSC) Home Location Register, (HLR) PSTN, ISDN, PSPDN, CSPDN Equipment ID register (EIR) and Authentication center (AuC) Visitor Location Register (VLR) • ISDN (Integrated Services Digital Network) • PSTN (Public Switched Telephone Network) • PSPDN (Packet Switched Public Data Net.) • CSPDN (Circuit Switched Public Data Net.)

15. Mobile Station (MS) • Mobile Equipment • International Mobile Equipment Identity (IMEI) number • Subscriber Identity Module (SIM) • Personal Identification Number (PIN) • International Mobile Subscriber Identity (IMSI) number • Enables access to subscribed services

16. Base Station Subsystem • Base Transceiver Subsystem (BTS) • House the radio transceivers the radio link protocols with mobile stations • Base Station Controller (BSC) • Manage the radio resources for one or more BTSs • Handle radio-channel set up, frequency hopping, and handovers

17. Network Subsystem • Mobile Switching Centre (MSC) • Home Location Register (HLR) • Visitor Location Register (VLR) • Authentication Center (AUC) • Equipment Identity Register (EIR) • Short Message Service (SMS)

18. Mobile Switching Centre (MSC) • Performs all switching/exchange functions • Handles • Registration • Authentication • Location updating • May connect to other networks • Gateway MSC (GMSC)

19. Home and Visitor Location Registers • Home Location Register (HLR) • Administrative information for all subscribers • IMSI number • actual phone number • permitted supplementary services • current location i.e. which VLR subscriber is currently registered with • parameters for authentication and ciphering • One HLR per GSM PLMN • Visitor Location Register (VLR) • Local database for a subset of user data, including data about all user currently in the domain of the VLR • Selected information from the HLR for all mobiles in MSC area • Often bundled with MSC (VLR domain tied in with MSC coverage)

20. Authentication Center (AUC) • Generate user specific authentication parameters on request of a VLR • Authentication parameters used for authentication of mobile terminals and encryption of user data on the air interface

21. Equipment Identity Register (EIR) • Register GSM mobile stations and user rights • Stolen or malfunctioning mobile stations can be locked

22. Short Message Service (SMS) • Use “always on” data channel (i.e., independent of the voice traffic channels) • Operate independently and concurrently with voice operations. • Transfer a message of size up to 160 characters to and from the mobile station. • A SMS Service Centre (SM-SC) serves as the message switching centre. • An external short message entity (ESME, message entity,) sends SMS message to the SM-SC

23. PC Short Message Service (SMS) GSM Network Subsystem SMS-GMSC PSDN SM SC BTS BSC SMS-IWMSC MSC VLR ESMEs HLR • SM-SC (Short Message Service Center): message switching centre • SMS-GMSC (Short Message Service Gateway MSC): SM-SCMSC • IWMSC (Interworking MSC): MSCSM-SC • ESME (external short message entity): a data terminal residing on external network

24. General Packet Radio Service (GPRS) • Improve GSM’s data transmission capacities (Circuit switching, low data rate 9.6 kbps) • 2.5G data service overlaid on an existing GSM network • Mobile station uses up to 8 timeslots (channels) for GPRS data connection from Mobile Station • Depending the coding, a transfer rate of up to 150 Kbps is possible, • GPRS provides packet mode transfer for applications with a selection of QoS parameters for service request;

25. Architecture of GPRS IP andX.25 GPRS Mobile station (MS) Gateway GPRS support node, GGSN Serving GPRS support node, SGSN Base Station Controller (BSC) Mobile Service Switching Center (MSC) Home Location Register, (HLR) GR GR:GPRS register, a part of HRL Equipment ID register (EIR) and Authentication center (AuC) Visitor Location Register (VLR)

26. GPRS Mobile Station • Three Classes • Class A - simultaneous circuit switched (GSM) and packet switched (GPRS) traffic • Class B- supports both GSM and GPRS connections but not both at the same time. One call is suspended for the duration of the other • Class C - handless both GPRS or GSM but can only be connected to one at the same time

27. GPRS Network Subsystem • Two new nodes introduced for packet data • Serving GPRS Support Node (SGSN) • monitors GPRS users • handles security and access control • may be regarded as the packet switched equivalent of the circuit-switched MSC • Gateway GPRS Support Node (GGSN) • internetworking functionality • routes incoming data to correct SGSN • translates between different protocols and formats

28. IPSec GPRS tunnel ON IP GPRSGeneral Packet Radio Service • Forwards IP from mobile device to Internet or Intranet via GPRS backbone network WWW IPSec Logical link over RAN

29. Third-Generation Mobile Communication System (3G) • Frequency Band • 1885~ 2025MHz and 2110~2200MHz • Capable of providing high-speed data transmission • 384kbps for mobile; 2Mbps for stationary • Multimedia Service

30. 3G Standards International Telecommunications Unit (ITU)

31. Two major 3G systems Universal Mobile Telecommunications System (UMTS) cdma2000

32. mobile Legacy Alternative Applications & signalling Network Access Services *) Network SCP Multimedia CSCF IP Networks R-SGW *) Mw Mh Ms CAP Mm Packet Domain Cx HSS *) CSCF Gr Mg Mr Gi Gi EIR MRF Gf Gi MGCF T-SGW *) Gc Iu BSS/ GERAN TE MT Gb GGSN Mc SGSN Multi-Media Domain R Um Gi A Gn Iu Iu PSTN/ UTRAN TE MT MGW MGW Legacy/External R Uu Nb Iu Mc Mc Nc MSC server GMSC server T-SGW *) Circuit-Switched Domain CAP CAP D C Applications HSS *) R-SGW *) & Services *) Mh UMTS Reference Model

33. UMTS - UTRA • UMTS Terrestrial Radio Access (UTRA) • Radio Network Subsystem • Air interface • W-CDMA • Node B • equivalent of a BTS • Radio Network Controller • supports a number of Node Bs • equivalent of a BSC

34. 3G, 2.5G and 2G BSC MSC Fixed Telephone Infrastructure GSM/GPRS BTS SGSN RNC GGSN Packet Data Infrastructure UMTS BTS Different radio access networks on the same core network

35. Radio Network Circuit Domain SS7 BTS HLR MSC/VLR PSTN BSC GMSC MSC/VLR IWF BTS Packet Domain BSC Public Public IP Network PDN Internet Internet A Interface PDSN/FA RP Interface BTS AAA Private IP Network Packet Data HA BSC Public Internet BTS1 BTS1 BTS1 BTS1 cdma2000 Mobile IP functionality- Foreign agent (FA) and Home agent (HA) Packet data service node (PDSN) – Equivalent of SSGN in GPRS Authentication, Authorization, and Accounting (AAA)

36. GSM/UMTSWSP CDMA WSP PDSN/FA/HA/Firewall GGSN/FA/HA/ Firewall SGSN PCF MSC/RNC BSC BS CGF BS BS BS Multi-mode terminal w/MobileIP client & IPSec Client Future of Wireless Networks • Current mobility is based on single wireless technologies. • Future will allow automatic configuration for seamless roaming amongst various wireless technologies…and, hence, greater coverage (ubiquitous). Enterprise Home AAA Server WLAN Gateway, HA, FA Corporate LAN Ethernet VPN Firewall 802.11 Access Points IP Backbone/ Internet WLAN Gateway & FA Public WLAN Ethernet 802.11 Access Points Mobile devices can connect to office networks anytime from anywhere….

37. Mobile IP • A standard proposed to solve the problem of Internet mobility

38. A Routing Example: 1.0.0.1  2.0.0.4 Ethernet B Network Prefix = 2.0.0 Host 4 Host 3 High-Speed Fiber Backbone Network Prefix = 3.0.0 Ethernet A Network Prefix = 1.0.0 Router B b b Host 2 Host 1 b 3.0.0.253 2.0.0.4 2.0.0.3 c Router A 2.0.0.253 a a c a Host 5 1.0.0.1 1.0.0.2 c 3.0.0.254 1.0.0.254 b b 3.0.0.252 4.0.0.5 Router C Host 1’s routing table 4.0.0.252 Ethernet C Network Prefix = 4.0.0

39. A Routing Example: 1.0.0.1  2.0.0.4 Ethernet B Network Prefix = 2.0.0 Host 4 Host 3 High-Speed Fiber Backbone Network Prefix = 3.0.0 Ethernet A Network Prefix = 1.0.0 Router B b b Host 2 Host 1 b 3.0.0.253 2.0.0.4 2.0.0.3 c Router A 2.0.0.253 a a c a Host 5 1.0.0.1 1.0.0.2 c 3.0.0.254 1.0.0.254 b b 3.0.0.252 Router A’s routing table 4.0.0.5 Router C 4.0.0.252 Ethernet C Network Prefix = 4.0.0

40. A Routing Example: 1.0.0.1  2.0.0.4 Ethernet B Network Prefix = 2.0.0 Host 4 Host 3 High-Speed Fiber Backbone Network Prefix = 3.0.0 Ethernet A Network Prefix = 1.0.0 Router B b b Host 2 Host 1 b 3.0.0.253 2.0.0.4 2.0.0.3 c Router A 2.0.0.253 a a c a Host 5 1.0.0.1 1.0.0.2 c 3.0.0.254 1.0.0.254 b b 3.0.0.252 Router B’s routing table 4.0.0.5 Router C 4.0.0.252 Ethernet C Network Prefix = 4.0.0

41. A Routing Example: 1.0.0.1  2.0.0.4 Ethernet B Network Prefix = 2.0.0 Host 3 High-Speed Fiber Backbone Network Prefix = 3.0.0 Ethernet A Network Prefix = 1.0.0 ? Router B b Host 2 Host 1 b 3.0.0.253 2.0.0.3 c Router A 2.0.0.253 a a c a Host 5 Host 4 1.0.0.1 1.0.0.2 c 3.0.0.254 1.0.0.254 b b b 3.0.0.252 Router B’s routing table 2.0.0.4 4.0.0.5 Router C 4.0.0.252 Ethernet C Network Prefix = 4.0.0

42. Mobility Solution • Use two IP addresses: • a fixed home address • a care-of address that changes at each new point of attachment

43. Entities and Relationships Mobile Node “visiting” a foreign link Mobile Node “at home” Foreign Link Foreign Agent Home Link – the link having the same network prefix as the node’s IP address Home Agent – a router on the mobile node’s home link. Foreign Link Foreign Agent

44. Care-of Address • Two conceptual types of care-of addresses • Foreign agent care-of address • IP address of the foreign agent • Collocated care-of address • An IP address temporarily assigned to a mobile node.

45. Three Mechanisms • Agent Discovery • Registration • Routing

46. Agent Discovery • Periodically broadcasts Agent Advertisements • Move Detection • Fails to hear an advertisement from that agent within the specified Lifetime • Assign a foreign agent or collocated care-of-address

47. Registration • Inform its home agent of its current care-of address • Deregister when it returns to its home link

48. Registering Care-of Address The mobile node, with the assistance of a foreign agent, sends a Registration Request with the care-of address information. 2 1 Mobile Node “visiting” a foreign link Home Agent Foreign Agent 4 3 When the home agent receives this request, it adds the necessary information to its routing table, and sends a Registration Reply back to the mobile node.

49. Deregistration Mobile Node returns to its home link 1. (de-)Registration Request Home Agent 2. (de-)Registration Reply

50. Routing Different Scenarios • Mobile Node → Correspondent Node • Correspondent Node → Mobile Node