ETSF10 Internet Protocols Network Layer Protocols

Transcription

1 ETSF10 Internet Protocols Network Layer Protocols 2012, Part 2, Lecture 3.1 Kaan Bür, Jens Andersson

2 Network Layer Protocols IPv4, IPv6 [ed.4 ch ] [ed.5 ch ] Transition from IPv4 to IPv6 [ed.4 ch.20.4] [ed.5 ch.22.4] ICMPv4, ICMPv6, ARP [ed.4 ch ] [ed.5 ch ] Special Topic: Virtual private networks (VPN) [ed.4 ch.32.1] [ed.5 ch ] 2

3 Network layer L3 is end-to-end L2 is host-to-host 3

4 Network layer: Routing L3 is end-to-end Two functions: Addressing Feedback 4

5 Internet Protocol IPv4 Addressing scheme Hierarchy Configuration Lookup Datagram format IPv6 Larger address space Better header format Extendible More secure Support for QoS 5

6 IPv4 addresses 32 bits = 4 bytes 2 32 = (2 8 ) 4 = = Classful vs. classless hierarchy Notations Dotted decimal Slash (CIDR) 6

7 Classless addressing Addresses in blocks Block size power of 2 N = 2 32-n 7

8 Exercise: Classless addressing /28 8

9 IPv6 addresses 128 bits = 16 bytes = > Notations 9

10 Global unicast addresses Identify individual computers TYPE AREA ISP ORGANISATION 10

11 A few special IPv6 addresses AUTOCONFIG 11

12 IPv4 datagram 12

13 Service type field 13

14 IPv6 datagram Simpler base header, flexible for extensions 14

15 IPv6 extension headers 15

16 Traffic Classes Packet priorities Congestion controlled Non-congestion controlled 16

17 IPv6 and QoS Flow label Identification of a stream TCP sessions Virtual connections Processing Flow label table Forwarding table Routing Algorithms still necessary But not run for every packet! Traffic class Classification of packets Queueing schemes Relation to delay TCP vs. UDP Congestion-controlled Non-congestion-controlled Other protocols RTP RSVP 17

18 Transition: IPv4 IPv6 Cannot happen overnight Too many independent systems Economic cost IPv4 address space lasted longer than expected Coexisence needed 18

19 Transition: (1) Dual stack Decision based on destination IP 19

20 Transition: (2) Tunneling A few IPv6 routers 20

21 Transition: (3) Header translation A few IPv4 routers 21

22 See you in 15 :) After the break ICMP ARP VPN 22

23 Internet Control Message Protocol ICMP Support protocol for IP Error reporting Query 23

24 ICMPv4 message types 24

25 ICMP message formats Error reporting Query messages 25

26 Redirection (error reporting type) Routing update for hosts More efficient when too many hosts DEFAULT ROUTER 26

27 Echo request and reply (query type) Is my destination alive? Network diagnostics IP layer Debugging tools Ping Traceroute 27

28 Traceroute Echo request 28

29 Exercise: ICMP in action Q: In what kind of network can a host never receive a redirection message? A: In a network with only one router 29

30 Changes to ICMP ICMPv4 Some unused functions ICMPv6 Same principle Some new functions Convergence Suits IPv6 better 30

31 Internetworking 31

32 Address mapping Internetworking Network of networks (Internet) Connected by routers Routers need information Logical (IP) physical (MAC) 32

33 Address resolution protocol (ARP) 33

34 ARP packet 34

35 Four use cases for ARP 35

36 Virtual Private Network (VPN) Overlay network Alternative to a real private network 36

37 An example VPN IPSec between routers 37

38 IPSec Transport mode Tunnel mode T H 38

39 Transport mode in action Data protected Headers unprotected Addresses fully visible 39

40 Tunnel mode in action Not used between hosts Entire packet protected New header inside tunnel 40

41 Internet security 41

42 Coming Up NAT, BOOTP, DHCP [ed.4 ch ] [ed.5 ch ] DNS [ed.4 ch ] [ed.5 ch.26.6] Mobile IP [-] [ed.5 ch.19.3] Special Topic: Wireless LAN [ed.4 ch.14.1] [ed.5 ch ] 42

43 Announcements TCP lab Submission via moodle No office hours after Thursday, 29/11 Deadline extended to Tuesday, 4/12 Review of questions on Wednesday, 5/12 Peer review of reports (just an idea, yet!) Term paper / self-reflection Introduction tomorrow 43