ETSF10 Part 3 Lect 1

Transcription

1 ETSF10 Part 3 Lect 1 IPv4 and IPv6, ICMP, RTP/RTCP, VoIP Jens A Andersson Electrical and Information Technology

2 IPv4 Recap Some header fields MTU Fragmentation

3 Figure Nt Network klayer in an internetwork it t 20.3

4 Figure 20.4 Position of IPv4 in TCP/IP protocol suite 20.4

5 Figure 20.5 IPv4 datagram format 20.5

6 Figure 19.1 Dotted-decimal notation and binary notation for an IPv4 address 19.6

7 Finding the network id and the Classful Classes A E Classless host id Net mask (Subnetting / subnet mask)

8 Figure 19.2 Finding the classes in binary and dotted-decimal notation 19.8

9 Table 19.2 Default masks for classful addressing 19.9

10 Figure 20.6 Service type or differentiated t d services 20.10

11 Figure 20.8 Protocol lfield and encapsulated ddata 20.11

12 Figure Example of checksum calculation in IPv

13 Figure Taxonomy of options in IPv

14 Figure 20.9 Maximum transfer unit it(mtu) 20.14

15 Fragmentation (IPv4) Needed if IP datagram size > MTU of next link Framgentation performed by the router that meets the problem Defragmentation performed by destination host

16 Figure Flags used in fragmentation ti 20.16

17 Figure Detailed fragmentation example 20.17

18 IPv6 Header Addresses

19 Figure IPv6 datagram header and payload 20.19

20 Figure Format of an IPv6 datagram 20.20

21 20.21 Table 20.6 Next header codes for IPv6

22 Figure IPv6 address in binary and hexadecimal colon notation 19.22

23 Table 20.7 Priorities for congestion-controlled traffic 20.23

24 Table 20.8 Pi Priorities iti for noncongestion-controlled t dtraffic 20.24

25 Table 20.9 Comparison between IPv4 and IPv6 packet headers 20.25

26 Figure Et Extension header types Performed by sender! } IPSec 20.26

27 Table Comparison between IPv4 options and IPv6 extension headers 20.27

28 Transition IPv4 -> IPv6 Cannot be made at one occasion Both protocols must coexist Networks nodes Hosts (remember not only computers are hosts) Economic costs versus actual need IPv4 address space lasts longer than expected CIDR (Classless Inter Domain Routing) NAT (Network Address Translation)

29 Figure Three transition strategies t 20.29

30 Figure Dual stack 20.30

31 Figure Tunneling strategy t 20.31

32 Figure Header translation ti strategy t 20.32

33 Table Header translation 20.33

34 ICMP Internet Control Message Protocol Supplementory support protocol for IP Error-reporting Queries

35 Figure 21.8 General format of ICMP messages 21.35

36 Notes on ICMP No ICMP error message will be generated in response to a datagram carrying an ICMP error message. No ICMP error message will be generated for a fragmented ddatagram that is not the first fragment. No ICMP error message will be generated for a datagram having a multicast t address. No ICMP error message will be generated for a dt datagram having a special iladdress such as or

37 Figure 21.9 Error-reporting messages 21.37

38 Figure Contents t of data field for the error messages 21.38

39 Figure Rdi Redirection concept 21.39

40 Figure Query messages ping 21.40

41 Figure Encapsulation of ficmp query messages 21.41

42 Figure Comparison of network klayers in version 4 and version

43 Table 21.3 Comparison of error-reporting messages in ICMPv4 and ICMPv

44 Table 21.4 Comparison of query messages in ICMPv4 and ICMPv

45 RTP, RTCP Real Time Protocol Real Time Control Protocol No delivery mechanism Uses UDP/IP Contributions Time-stampning Sequencing Mixing

46 Figure RTP 29.46

47 Figure RTP packet header format 29.47

48 Figure Time relationship 29.48

49 Figure Jitter 29.49

50 Figure Timestamp 29.50

51 Figure Playback kbuffer 29.51

52 Sequence numbers Packets can be delivered out of order We must order the packets in the playback buffer. Playout according to time stamps fixes lost packets.

53 Table 20.1 Payload types 29.53

54 Note RTP uses a temporary even-numbered UDP port

55 RTCP RTP only carries data RTCP Control messages: Flow control Service quality Feedback to source

56 Figure RTCP message types 29.56

57 Sender report Sent periodically by active senders Statistics Transmission Reception Absolute timestamp # of seconds since Receiver can synch RTP messages Important to synch audio and video

58 Receiver report Sent by passive (non sending) listeners Inform senders about QoS

59 Note RTCP uses an odd-numbered d UDP port number that t follows the port number selected for RTP

60 Voice over IP (VoIP) Internet telephony SIP Session Initiation Protocol H.323 ITU standard

61 SIP Establish, manage, terminate multimedia sessions Text-based Six messages defined

62 Figure SIP messages 29.62

63 Figure SIP address formats 29.63

64 Figure SIP simple session 29.64

65 Figure Tracking the callee 29.65

66 H.323 Allows for communication telephone -- computer

67 Figure H.323 architecture t 29.67

68 Figure H.323 protocols 29.68

69 Figure H.323 example 29.69