Clase Nº4. Jorge Sa Silva. University of Coimbra Portugal

Transcription

1 Clase Nº4 Jorge Sa Silva University of Coimbra Portugal

2 Outline Multicast Future Internet IPv6 QoS Mobile IP 2

3 3

4 IGMP Routing Protocols Router Router Router Router Router Router Router Router Router Router 4

5 Ethernet Wireless or satellites (broadcast) 5

6 Addresses IGMP Routing algorithms Present solutions - protocols Source Specific Multicast (SSM) 6

7 Classe A 0 netid hostid Classe B 1 0 netid hostid Classe C netid hostid Classe D multicast address Classe E uso futuro 7

8 Internet Group Message Protocol Router Router Router Router Router Router Router Router Router Router 8

9 Flooding Spanning Trees Reverse Path Forwarding RPF e Prunes Steiner Trees Center-Based Trees 9

10 To route the data only to multicast members; Optimized routes from the sources to destinations; No loops; Distributed routes; Support dynamic members. 10

11 Easy to implement Simple Use of resources 11

12 E A 3 3 B 7 1 D F C 12

13 A C 3 3 B 7 1 D 4 E 1 5 F A 5 1 B 6 2 D 4 E 3 7 F A 5 1 B 6 2 D 4 E 3 7 F C C 13

14 Prune messages Algorithm Periodic messages Dynamic groups 14

15 Prune messages Graft messages Dynamic groups 15

16 A 5 1 B 6 2 D 4 E 3 7 F C E A 5 1 B 6 2 D F C 16

17 Tree with a central node Join and leave messages (IGMP) Less information Unidirectional and bi-directional trees Problem: centre! 17

18 Dense-mode Sparse-mode 18

19 Distance-vector RPF Tunnels 19

20 C C Ethernet Ethernet A B A B Ethernet D RPF, prune and graft 20

21 A 5 1 B 6 2 D 4 E 3 7 F A 5 1 B 6 2 D 4 E 3 7 F C C CBT 21

22 PIM-SM Multicast Source Discovery Protocol Multicast Border Gateway Protocol 22

23 Different ISPs Compatibility of internal routing protocols Address allocation 23

24 IGMPv3 MLDv2 Allowed sources Advantages 24

25 25

26 Number of multicast addresses Multicast-Ready Address allocation Flags Scope Group ID 26

27 Ordered transmission and without errors TCP vs UDP Reliable Muticast Unreliable Semireliable Reliable 27

28 Statistically reliable (%) K-reliable Sufficiently reliable (timeouts) 28

29 Source ordering Total ordering 29

30 It is necessary to maintain a list for all receivers that already received ACKs. Only after receiving all ACKs (from all receivers) to a specific data block, the source will delete that block in memory. ACKs explosion 30

31 The source can implement timeout mechanisms The performance of source-initiated protocols are dependent of the number of participants. A multicast group with a large number of members implies a large number of positive ACKs, and a large number of NACKs in instable environments, 31

32 When a receiver detects that it doesn t receive a packet, it must wait a random period and sends a NACK to the source and to all receivers. This procedure reduces the number of NACKs in the system. This procedure can only be applied in small networks (where the number of participants is low). 32

33 Tree Ring These protocols require less memory, the source doesn t need to be aware of all receivers and the system is not dependent of the number of participants. 33

34 The missing information is recovered by redundant information. 34

35 Fragmentation/desfragmentation Address/Routing 35

36 32 bits Networks ID Host ID Routing 36

37 Dotted-decimal notation Ex:

38 Routing and management Subnetting Sub-network management Ex: /24 38

39 1) IP address: Subnet Mask: Binary: ) IP address: Subnet Mask: Binary: (Network , terminal 9) 39

40 Binary Decimal

41 Classe A 0 netid hostid Classe B 1 0 netid hostid Classe C netid hostid Classe D multicast address Classe E uso futuro 41

42 Mais fragmentos Numero do primeiro elemento Identificador do Pacote Mais fragmentos Numero do primeiro elemento Identificador do Pacote Mais fragmentos Numero do primeiro elemento Identificador do Pacote 42

43 32 bits Version IHL TOS Total length Identification Flags Fragment offset Time to live Protocol Header checksum 20 bytes Source IP address Destination IP address Options Padding 4-40 bytes User data 43

44 VER (4 bits) Version (version 4) IHL (4 bits) Internet Header Length units of 4 bytes. By default it is 5 (20 bytes). This is necessary as the header length is not constant (options). ToS (8bits) Type of Service TL (16 bits) Total Length datagram length (bytes), header+data 44

45 ID (16 bits) Identify the datagrams from the same segment. Flag (3 bits) Don t fragment More fragments FO (3 bits) Fragment position in the original datagram (unities of 8 bytes) TTL (8 bits) Time To Live. PROT (8 bits) Protocol Header Checksum (16 bits) 45

46 46

47 Rede Router A Rede Router B Rede Router C Rede Router B Estação na rede Encaminhamento Directo Directo

48 Address allocation poorly managed at the beginning Solutions Address re-distribution (?) IPv6 NAT 48

49 Mapping of public addresses private addresses a class A) a (1 network of of class B) a (255 networks of class C) NAT (using ports) Static Dynamic Overloading DHCP Security support (16 networks Internet Rede Privada 49

50 IANA Internet Assigned Numbers Authority Public addresses Private addresses NAT (Network Adress Translation) 50

51 Adresses Routing Anycast Auto-configuration Multicasting QoS support Security 51

52 32 bits Version Traffic class Flow label Payload length Next Header Hop limit Source IP address 40 bytes Destination IP address Base Header Extension Header 1... Extension Header n Data 52

53 Hop by Hop Options Header Destination Options Header Routing Header Fragment Header Authentication Header Encapsulation Security Payload Header IPv6 Header Next Header = Routing Routing Header Next Header = TCP TCP Header Data 53

54 v4: v6: fce0:a3c2:0000:2020:aa63:43a4:0000:a1a1 54

55 Unicast TLA - Top-Level Aggregation Identifier RES - Reserved for future use NLA - Next-Level Aggregation Identifier SLA - Site-Level Aggregation Identifier Interface ID - Interface Identifier Multicast 55

56 First bits Representation Type of address 00 0 (128 bits) ::/128 Não especificado 00 1 (128 bits) ::1/128 Endereço loop-back FF00::/8 Endereços multicast FE80::/10 Endereços link-local FEC0::/10 Endereços site-local restantes Endereços globais unicast 56

57 Rede IPv 6 Router IPv 4 IPv 4 IPv 4 IPv 4 Router Rede IPv 6 57

58 Applications Data ( , FTP, Telnet, WWW) Audio (Voice over IP, Hi-fi) Video (HDTV, VoD, videoconferencing) Distributed processing (CAD, simulations) Other (virtual reality, tele-medicine) 58

59 IP Quality of Service What is it? Different levels of service for different types of traffic Relevant parameters Throughput Delay Jitter Loss Fairness Competing traffic flows Provide level of service according to SLAs 59

60 The need for quality of service Isn't over-provisioning enough to solve IP QoS problems? Network resources (e.g., bandwidth) are not infinite Existing network resources are a trade-off between cost/investment and performance There is the need to guarantee the agreed service level to applications, even when resources are not enough QoS is also a business opportunity 60

61 IP QoS provision problems How to guarantee that a network initially engineered for the support of elastic traffic (the Internet) can properly carry inelastic traffic? The only networking technology designed from scratch for the support of all types of traffic is ATM How to guarantee that applications with different needs get the resources they need (and that have paid for) even under global resource shortage? How to guarantee fairness among different traffic flows? 61

62 Needs of applications Throughput Peak rate Mean rate Delay Maximum delay Delay variation (jitter, delay jitter) Losses Due to congestion Error rate 62

63 Transit delay ITU-T Rec. G.114 defines three categories of applications in terms of end-to-end delay Delay < 150 ms acceptable delay for most applications 150 < delay < 400 ms significant delay for some applications Delay > 400 ms unacceptable delay for most applications (namely telephony and conferencing) 63

64 Loss/Error rate Acceptable loss/error rates 10-4, for voice applications and file transfer applications 10-6, for interactive data applications 10-7, for image transfer applications 10-8, for interactive compressed image transfer applications 64

65 Delay and throughput needs Delay (ms) File transfer 100 Interactive data Still images Intensive data Mainframe interconn Voice Audio Hi-Fi VoD/ Moving images HDTV Virtual reality Throughput (Mbps) 65

66 Data Network Best-effort paradigm New paradigms Integrated Services Differentiated Services 66

67 Routers Resource procedures Individual and group flows 67

68 Guaranteed Services (GS) Controlled Load Services (CLS) 68

69 Unicast / Multicast IPv4 / IPv6 Soft-State 69

70 Type of Service Per Hop Behaviour (PHBs) Service Level Agreement (SLAs) 70

71 Router Router Router Router Router Router Router Router Router 71

72 Layer 2 Layer 3 72

73 HA FA Permanent address Care-of-address Foreign Agent Mobile Node Home Agent Corresponding Agent Corresponding node 73

74 Overcome the triangle routing problem But adds complexity Learn the new COA Notify protocol to the alert the CN Anchor foreign agent Foreign Agent Mobile Node Corresponding Agent Home Agent Corresponding node 74

75 IP Networking Organisations rely more and more on information processing Networking plays a vital role in (distributed) information processing There is a growing demand for bandwidth Increasing utilisation Many applications rely on high bandwidth consumption Information systems heavily rely on networking IP networking is ubiquitous If applications are carried over IP they will also be ubiquitous 75

76 CN Rede Hospedeira FA HA Rede Base MN Pacote IP original Novo Cabeçalho Cabeçalho Original Source=HA Dest=COA Source)CN Dest=MN 76

77 Discovery Protocol Registration Procedure Encapsulation Procedure 77

78 Sequence numbers Life-Time Flags COAs 78

79 Basic (RFC 2003) Minimum (RFC2004) Generic Routing Encapsulation (RFC 1701) 79

80 128 bits addresses Autoconfiguration Plug and Play Low process in routers Path MTU Discovery Reduced routing tables Simplified headers 80

81 v4: v6: fce0:a3c2:0000:2020:aa63:43a4:0000:a1a 1 81

82 Nodes mobile-ready Redirects There in no FA 82