Networks Neeli R. Prasad

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1 Networks Neeli R. Prasad, Associate Professor Head of Wireless Security and Sensor Networks Networking and Security Aalborg University Niels Jernes Vej 12, Room #: A Aalborg East, Denmark Tel.:

2 Outline Networks?? Why do we need it? OSI 7-layer architecture Existing Standards IEEE Protocol Stack and architecture

3 Networks. What is it?

4 In information technology, a network is a series of points or nodes interconnected by communication paths. Networks can interconnect with other networks and contain subnetworks. The most common topology or general configurations of networks include the bus, star, Token Ring, and mesh topologies. Networks can also be characterized in terms of spatial distance as local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs).

6 Networks WAN MAN WLAN WPAN

7 Fundamental aspects of network Design and Analysis Architecture Layering Topology design Protocols Pt.-to-Pt. Multiple access End-to-end Algorithms Error recovery Routing Flow Control Analysis tools Probabilistic modeling Queueing Theory

8 Switching Techniques Circuit Switching Dedicated resources Packet Switching Shared resources Virtual Circuits Data

9 Circuit Switching Each session is allocated a fixed fraction of the capacity on each link along its path Dedicated resources Fixed path If capacity is used, calls are blocked E.g., telephone network Advantages of circuit switching Fixed delays Guaranteed continuous delivery Disadvantages Circuits are not used when session is idle Inefficient for bursty traffic Circuit switching usually done using a fixed rate stream (e.g., 64 Kbps) Difficult to support variable data rates

10 Packet Switching Data packet switching Route chosen on packet-by-packet basis Different packets may follow different routes Packets may arrive out of order at the destination E.g., IP (The Internet Protocol) Virtual Circuit packet switching All packets associated with a session follow the same path Route is chosen at start of session Packets are labeled with a VC# designating the route The VC number must be unique on a given link but can change from link to link Imagine having to set up connections between 1000 nodes in a mesh Unique VC numbers imply 1 Million VC numbers that must be represented and stored at each node E.g., ATM (Asynchronous transfer mode)

11 Virtual Circuit Packet Switching For data, addressing information must uniquely distinguish each network node and session Need unique source and destination addresses For virtual circuits, only the virtual circuits on a link need be distinguished by addressing Global address needed to set-up virtual circuit Once established, local virtual circuit numbers can then be used to represent the virtual circuits on a given link: VC number changes from link to link Merits of virtual circuits Save on route computation Need only be done once at start of session Save on header size Facilitate QoS provisioning More complex Less flexible

12 Circuit vs packet switching Advantages of packet switching Efficient for bursty data Easy to provide bandwidth on demand with variable rates Disadvantages of packet switching Variable delays Difficult to provide QoS assurances (Best-effort service) Packets can arrive out-of-order Switching Technique Network service Circuit switching => Synchronous (e.g., voice) Packet switching => Asynchronous (e.g., Data) Virtual circuits => Connection oriented Data => Connectionless

13 Can circuit switched network be used to support data traffic? Can packet switched network be used for connection oriented traffic (e.g., voice)? Need for Quality of service (QoS) mechanisms in packet networks Guaranteed bandwidth Guaranteed delays Guaranteed delay variations Packet loss rate Etc...

14 Why do we need it?

15 Services Cel l u l a r Net w o r k Mall Netw ork Fr ien d s PAN Store Netw ork Electr o n ic billboard Sun Warm Co r e PAN Friend s PAN Sp o u se s PAN Ho me Net w or k Remote personal sensor Identification sensor Internet Fr ien d s PAN Opera server Source: MAGNET Smart Shopping Use Case

16 Networks coverage area Macro mobility AAA AS IP Backbone Network Micro mobility BR BR Micro mobility BR End2End IP Access Networks Fixed Wireless Access AP ER Internet Service Provider ER ER IP based 2G/3G Networks ER Satellite Networks WLAN WPAN xdsl GPRS UMTS Pico Coverage AAA AS BR ER Micro and Macro coverage Authentication, Authorization and Accounting Server Application Server Border Router Edge Router

17 OSI 7-layer architecture

19 TCP Layering

20 Internet Protocols

21 TCP layers/architecture data flows up/down stack each layer on write adds header/addr. info. This process is called encapsulation on read, data is demultiplexed - decide which protocol upstairs to feed it to, and decapsulated demux example: from link layer, packet could go to IP, ARP, RARP, Proxy ARP

22 Transport/Network Layer Network layer - hides physical layer ip is hop by hop Transport layer - end to end, error correction tcp is end to end

23 Addressing/encapsulation Application - Domain Name System (sirius.cs.pdx.edu) sockets tcp/udp, use ports, 16 bit unsigned ints ip-uses IP address, 32 bit int (net, subnet, host) link layer, ethernet uses IEEE 48 bit MAC address

24 Encapsulation

25 IP Addressing per interface. each i/f has (ip address, broadcast address, subnet mask) (network, subnet, host) written in dotted decimal in network byte order (big-endian) (0..255) 5 classes, A to E, each takes a bit at the hi-order end

26 IP addresses 3 types of IP address (topographical) unicast» , broadcast» , ,» multicast»

27 uniqueness must be handled by humans various IP authorities at this point, Regional Inet Registries U.S. authority is ARIN (NA, SA, Africa), APNIC for asia, RIPE for europe (there are more now) ISP feeding chain in U.S., ends up at ARIN IP (v4,v6) addresses + A.S. numbers (later) DNS was from Internic: rs.internic.net, Network Solutions ( ICANN ( now broken up into separate registration companies

28 Data Link Layer Switching Bridges from 802.x to 802.y Local Internetworking Spanning Tree Bridges Remote Bridges Repeaters, Hubs, Bridges, Switches, Routers, Gateways Virtual LANs

29 Data Link Layer Switching Multiple LANs connected by a backbone to handle a total load higher than the capacity of a single LAN.

30 Repeaters, Hubs, Bridges, Switches, Routers and Gateways (a) Which device is in which layer. (b) Frames, packets, and headers.

31 hub. bridge. switch.

32 Virtual LANs A building with centralized wiring using hubs and a switch.

33 Why VLANs if everything interconnects? LAN represents organizational hierarchy rather than geography Security Traffic Load/separation (research vs production) Limiting Broadcasts Legitimate (i.e ARP) Storms Do rewiring in software

34 Bridges from 802.x to 802.y Operation of a LAN bridge from to

35 The IEEE 802 frame formats.

36 Existing Standards

37 Wireless Networking Standards WAN 3GPP, 3GPP2, EDGE, GSM MAN WiMAX WLAN WiFi Bluetooth ( a) UWB ( a) WPAN

38 IEEE WPAN Standards Q1CY a EQ3CY a EQ1CY Bluetooth v1.2 ( a) New Features Adaptive Frequency Hopping Enhanced Voice Processing Faster Connection Setup Backwards Compatible Ultrawideband ( a) Supports Bit Rates Greater than 100Mbps with 10m Radius All-CMOS, low power, low cost since low cost design are feasible Uses ~ 7GHz of Spectrum

39 Bluetooth Architecture

40 The Bluetooth Protocol Stack The version of the Bluetooth protocol architecture.

41 The Bluetooth Frame Structure A typical Bluetooth data frame.

42 802.11b 2.4GHz, CCK, 11 Mbps, Q IEEE WLAN Standards a 5GHz, OFDM, 54 Mbps, Q PHY Standards g 2.4GHz, OFDM, 54 Mbps, Q n 100 Mbps, End c Bridging Tables Incorporated into 802.1D Q d International Roaming Q Regulatory Standards h European Regulatory Extensions Q j Japanese Regulatory Extensions Q h+d Q Enhancements Standards f Inter- Access Point Protocol Q WiFi Protected Access (WPA), Security subset of i Draft Q i Enhanced Security Q e Quality of Services Q k Radio Resource Management Q m Maintenance of the Standard

43 IEEE Protocol Stacks Part of the protocol stack.

44 Standards Roadmap GHz, LOS Q c Interoperability & Testing Q a 2-11 GHz, Non- LOS, 75Mbps Q REVd 2-11 GHz, Non- LOS, 75 Mbps at 20 MHz CH, System Profiles, Q e 2-6 GHz, Non-LOS, 15Mbps at 5 MHz, Q is fixed wireless broadband air interface between 10 and 66GHz. Within this area, 16a, 16d, and 16e, you have actually WiMAX.

45 What is WiMAX? WiMAX (Worldwide interoperability for Microwave Access) is a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL. WiMAX will provide fixed, nomadic, portable and, eventually, mobile wireless broadband connectivity without the need for direct line-of-sight with a base station. In a typical cell radius deployment of three to ten kilometers, WiMAX Forum Certified systems can be expected to deliver capacity of up to 40 Mbps per channel, for fixed and portable access applications. This is enough bandwidth to simultaneously support hundreds of businesses with T-1 speed connectivity and thousands of residences with DSL speed connectivity. Mobile network deployments are expected to provide up to 15 Mbps of capacity within a typical cell radius deployment of up to three kilometers. It is expected that WiMAX technology will be incorporated in notebook computers and PDAs in 2006, allowing for urban areas and cities to become MetroZones for portable outdoor broadband wireless access

46 WiMAX All the segments below will co-exist: Last Mile High Throughput Access for Business and some Residential (PTP & PMP) (external antennas) Integrated WiFi & WiMAX (internal antennas). Within the home, Wi-Fi will offer the connection point between the PC and the access point, and between the PC and other devices such as phones, PDAs, printers you can use Bluetooth. WiMAX in PC, minipci and PCMCIA cards HotSpot Backhaul 3G Backhaul

47 The Protocol Stack The Protocol Stack. OFDM in 2GHz and 5 GHz

48 The Physical Layer The transmission environment.

49 Americas Europe Wireless WAN 2G 2.5G/3G 3G/3.5G TDMA EGDE/EGPRS ~384 Kbps (Avg/user ~80Kbps) HSDPA ~10 Mbps ASIA India China GSM GPRS ~171 Kbps (Avg/user ~30Kbps) UMTS (WCDMA) ~2 Mbps (Avg/user ~300Kbps) TD-SCDMA Japan PDC UMTS (WCDMA) ~2 Mbps (Avg/user ~300Kbps) HSDPA ~10 Mbps US S. Korea Japan cdmaone CDMA2000 1x ~144 Kbps (Avg/user ~60Kbps) CDMA2000 1x EVDO (data only) ~2.4 Mbps (Avg/user ~300Kbps) CDMA2000 1x EVDV (data/voice) ~2.4 Mbps (Avg/user ~300Kbps) Digital Voice & CSD Kbps Packet Data Kbps Hi Speed Data 2 10 Mbps

50 Cellular Radio Network Architecture Radio base station Switching and routing Roaming Home network Interconnect Other Networks (GSM, fixed, Internet, etc.) Visited network

51 Third Generation Mobile Phones The UMTS Standard Third generation (3G) mobile phones are characterised by higher rates of data transmission and a richer range of services Universal Mobile Telecommunications System (UMTS) is one of the new 3G systems The UMTS standards work started in ETSI but was transferred to a partnership of regional standards bodies known as 3GPP in 1998 the GSM standards were also moved to 3GPP at a later date UMTS introduces a new radio technology into the access network Wideband Code Division Multiple Access (W-CDMA) An important characteristic of UMTS is that the new radio access network is connected to an evolution of the GSM core network

52 UMTS Network Architecture VLR HLR/AuC RNC Switching and routing Home network USIM RNC Other Networks (GSM, fixed, Internet, etc.) New radio access network Visited core network (GSM-based)

54 Conclusions. for today

55 To be continued.

Digital Communication Networks

Digital Communication Networks MIT PROFESSIONAL INSTITUTE, 6.20s July 25-29, 2005 Professor Muriel Medard, MIT Professor, MIT Slide 1 Digital Communication Networks Introduction Slide 2 Course syllabus