IPv4 Addressing and IPv6

Transcription

1 IPv4 Addressing and IPv6 Antonio Carzaniga Faculty of Informatics Università della Svizzera italiana December 5, 2016

2 Outline IPv4 Addressing network addresses classless interdomain routing address allocation and routing longest-prefix matching

3 Outline IPv4 Addressing network addresses classless interdomain routing address allocation and routing longest-prefix matching IPv6 motivations and design goals datagram format comparison with IPv4 extensions

4 Interconnection of Networks

5 Interconnection of Networks subnet

6 32-bit addresses IPv4 Addressing

7 IPv4 Addressing 32-bit addresses AnIPaddressisassociatedwithaninterface,notahost ahostwithmorethanoneinterfacemayhavemorethanone IP address

8 IPv4 Addressing 32-bit addresses AnIPaddressisassociatedwithaninterface,notahost ahostwithmorethanoneinterfacemayhavemorethanone IP address The assignment of addresses over an Internet topology is crucial to limit the complexity of routing and forwarding

9 IPv4 Addressing 32-bit addresses AnIPaddressisassociatedwithaninterface,notahost ahostwithmorethanoneinterfacemayhavemorethanone IP address The assignment of addresses over an Internet topology is crucial to limit the complexity of routing and forwarding Thekeyideaistoassignaddresseswiththesameprefixto interfaces that are on the same subnet

10 Classless Interdomain Routing

11 Classless Interdomain Routing All interfaces in the same subnet share the same address prefix e.g.,inthepreviousexamplewehave , , , and

12 Classless Interdomain Routing All interfaces in the same subnet share the same address prefix e.g.,inthepreviousexamplewehave , , , and Network addresses prefix-length notation: address/prefix-length

13 Classless Interdomain Routing All interfaces in the same subnet share the same address prefix e.g.,inthepreviousexamplewehave , , , and Network addresses prefix-length notation: address/prefix-length e.g., /24, /24, /24, and /24

14 Classless Interdomain Routing All interfaces in the same subnet share the same address prefix e.g.,inthepreviousexamplewehave , , , and Network addresses prefix-length notation: address/prefix-length e.g., /24, /24, /24, and / /24 means that all the addresses share the same leftmost 24 bits with address

15 Classless Interdomain Routing All interfaces in the same subnet share the same address prefix e.g.,inthepreviousexamplewehave , , , and Network addresses prefix-length notation: address/prefix-length e.g., /24, /24, /24, and / /24 means that all the addresses share the same leftmost 24 bits with address This addressing scheme is not limited to entire bytes. For example, a network address might be /27

16 Network address /27 Examples

17 Examples Network address /27 subnet { }} { two

18 Examples Network address /27 subnet { }} { two ?

19 Examples Network address /27 subnet { }} { two ? two

20 Examples Network address /27 subnet { }} { two ? two ?

21 Examples Network address /27 subnet { }} { two ? two ? two

22 Examples Network address /27 subnet { }} { two ? two ? two ?

23 Examples Network address /27 subnet { }} { two ? two ? two ? two

24 What is the range of addresses in /27? Ranges

25 Ranges What is the range of addresses in /27? subnet { }} { two

26 Ranges What is the range of addresses in /27? subnet { }} { two two two two two two

27 Ranges What is the range of addresses in /27? subnet { }} { two two two two two two

28 Network addresses, mask notation: address/mask Net Mask

29 Net Mask Network addresses, mask notation: address/mask Aprefixoflengthpcorrespondstoamask M = ptimes { }} { p times { }} { 00 0 two e.g., /27= /

30 Net Mask Network addresses, mask notation: address/mask Aprefixoflengthpcorrespondstoamask M = ptimes { }} { p times { }} { 00 0 two e.g., /27= / /8=?

31 Net Mask Network addresses, mask notation: address/mask Aprefixoflengthpcorrespondstoamask M = ptimes { }} { p times { }} { 00 0 two e.g., /27= / /8= /

32 Net Mask Network addresses, mask notation: address/mask Aprefixoflengthpcorrespondstoamask M = ptimes { }} { p times { }} { 00 0 two e.g., /27= / /8= / /24=?

33 Net Mask Network addresses, mask notation: address/mask Aprefixoflengthpcorrespondstoamask M = ptimes { }} { p times { }} { 00 0 two e.g., /27= / /8= / /24= /

34 Net Mask Network addresses, mask notation: address/mask Aprefixoflengthpcorrespondstoamask M = ptimes { }} { p times { }} { 00 0 two e.g., /27= / /8= / /24= / /32=?

35 Net Mask Network addresses, mask notation: address/mask Aprefixoflengthpcorrespondstoamask M = ptimes { }} { p times { }} { 00 0 two e.g., /27= / /8= / /24= / /32= /

36 Net Mask Network addresses, mask notation: address/mask Aprefixoflengthpcorrespondstoamask M = ptimes { }} { p times { }} { 00 0 two e.g., /27= / /8= / /24= / /32= / In Java:

37 Net Mask Network addresses, mask notation: address/mask Aprefixoflengthpcorrespondstoamask M = ptimes { }} { p times { }} { 00 0 two e.g., /27= / /8= / /24= / /32= / In Java: int match(int address, int network, int mask) { return (address & mask) == (network & mask); }

38 Classless Interdomain Routing

39 Classless Interdomain Routing This any-length prefix scheme is also called classless interdomain routing(cidr) as opposed to the original scheme which divided the address space in classes address class prefix length A 8 B 16 C 24

40 Classless Interdomain Routing This any-length prefix scheme is also called classless interdomain routing(cidr) as opposed to the original scheme which divided the address space in classes address class prefix length A 8 B 16 C 24 Whyistheideaofthecommonprefixsoimportant?

41 Classless Interdomain Routing This any-length prefix scheme is also called classless interdomain routing(cidr) as opposed to the original scheme which divided the address space in classes address class prefix length A 8 B 16 C 24 Whyistheideaofthecommonprefixsoimportant? Routers outside a(sub)network can ignore the specifics of each address within the network there might be some 64 thousands hosts in /16, buttheyallappearasoneaddressfromtheoutside

42 Example: Good Address Allocation

43 Example: Bad Address Allocation

44 Allocation of Address Blocks

45 Allocation of Address Blocks thedude.org / /24 maude.com ISPX /16 bowling.edu /24 Internet

46 Allocation of Address Blocks thedude.org / /24 maude.com ISPX /16 bowling.edu /24 Internet /24 margie.net ISPX /16

47 Allocation of Address Blocks thedude.org / /24 maude.com ISPX /16 bowling.edu /24 Internet /24 margie.net ISPX / /24

48 Longest-Prefix Matching

49 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix

50 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., forwarding table network port / / / / / / /16 4

51 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., ? forwarding table network port / / / / / / /16 4

52 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., forwarding table network port / / / / / / /16 4

53 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., ? forwarding table network port / / / / / / /16 4

54 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., forwarding table network port / / / / / / /16 4

55 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., ? forwarding table network port / / / / / / /16 4

56 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., forwarding table network port / / / / / / /16 4

57 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., ? forwarding table network port / / / / / / /16 4

58 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., forwarding table network port / / / / / / /16 4

59 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., ? forwarding table network port / / / / / / /16 4

60 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., forwarding table network port / / / / / / /16 4

61 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., ? forwarding table network port / / / / / / /16 4

62 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., forwarding table network port / / / / / / /16 4

63 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., ? forwarding table network port / / / / / / /16 4

64 Longest-Prefix Matching In choosing where to forward a datagram, a router chooses the entry that matches the destination address with the longest prefix E.g., forwarding table network port / / / / / / /16 4

65 Special Addresses IPv4 defines a number of special addresses or address blocks

66 Special Addresses IPv4 defines a number of special addresses or address blocks Private, non-routable address blocks /8, /12, and /16

67 Special Addresses IPv4 defines a number of special addresses or address blocks Private, non-routable address blocks /8, /12, and /16 Default route /0

68 Special Addresses IPv4 defines a number of special addresses or address blocks Private, non-routable address blocks /8, /12, and /16 Default route /0 Loopback(a.k.a., localhost) /8

69 Special Addresses IPv4 defines a number of special addresses or address blocks Private, non-routable address blocks /8, /12, and /16 Default route /0 Loopback(a.k.a., localhost) /8 IP Multicast /4

70 Special Addresses IPv4 defines a number of special addresses or address blocks Private, non-routable address blocks /8, /12, and /16 Default route /0 Loopback(a.k.a., localhost) /8 IP Multicast /4 Broadcast /32

71 New-generation IP IPv6

72 IPv6 New-generation IP Why?

73 IPv6 New-generation IP Why? theipv4addressspaceistoosmall

74 IPv6 New-generation IP Why? theipv4addressspaceistoosmall Given the obvious difficulty of replacing IPv4, the short-term benefits of IPv6 are debatable

75 IPv6 New-generation IP Why? theipv4addressspaceistoosmall Given the obvious difficulty of replacing IPv4, the short-term benefits of IPv6 are debatable Nobody questions the long-term vision

76 IPv6 New-generation IP Why? theipv4addressspaceistoosmall Given the obvious difficulty of replacing IPv4, the short-term benefits of IPv6 are debatable Nobody questions the long-term vision Also, IPv6 improves various design aspects of IPv4

77 IPv6 Datagram Format 0 31

78 IPv6 Datagram Format 0 31 vers.

79 IPv6 Datagram Format 0 31 vers. traffic class

80 IPv6 Datagram Format 0 31 vers. traffic class flow label

81 IPv6 Datagram Format 0 31 vers. traffic class payload length flow label

82 IPv6 Datagram Format 0 31 vers. traffic class payload length flow label next hdr

83 IPv6 Datagram Format 0 31 vers. traffic class payload length flow label next hdr hop limit

84 IPv6 Datagram Format 0 31 vers. traffic class payload length flow label next hdr hop limit source address

85 IPv6 Datagram Format 0 31 vers. traffic class payload length flow label next hdr hop limit source address destination address

86 IPv6 Datagram Format 0 31 vers. traffic class payload length flow label next hdr hop limit source address destination address...

87 Expanded addressing IPv6 Main Design Features

88 IPv6 Main Design Features Expanded addressing 128-bit addresses

89 IPv6 Main Design Features Expanded addressing 128-bit addresses anycast address

90 IPv6 Main Design Features Expanded addressing 128-bit addresses anycast address Header format simplification

91 IPv6 Main Design Features Expanded addressing 128-bit addresses anycast address Header format simplification efficiency: reducing the processing cost for the common case

92 IPv6 Main Design Features Expanded addressing 128-bit addresses anycast address Header format simplification efficiency: reducing the processing cost for the common case bandwidth: reducing overhead due to header bytes

93 IPv6 Main Design Features Expanded addressing 128-bit addresses anycast address Header format simplification efficiency: reducing the processing cost for the common case bandwidth: reducing overhead due to header bytes Improved support for extensions and options

94 IPv6 Main Design Features Expanded addressing 128-bit addresses anycast address Header format simplification efficiency: reducing the processing cost for the common case bandwidth: reducing overhead due to header bytes Improved support for extensions and options Flow labeling

95 IPv6 Main Design Features Expanded addressing 128-bit addresses anycast address Header format simplification efficiency: reducing the processing cost for the common case bandwidth: reducing overhead due to header bytes Improved support for extensions and options Flow labeling special handling and non-default quality of service

96 IPv6 Main Design Features Expanded addressing 128-bit addresses anycast address Header format simplification efficiency: reducing the processing cost for the common case bandwidth: reducing overhead due to header bytes Improved support for extensions and options Flow labeling special handling and non-default quality of service e.g., video, voice, real-time traffic, etc.

97 What is Missing from IPv4?

98 Fragmentation What is Missing from IPv4?

99 What is Missing from IPv4? Fragmentation IPv6 pushes fragmentation onto the end-systems

100 What is Missing from IPv4? Fragmentation IPv6 pushes fragmentation onto the end-systems efficiency

101 What is Missing from IPv4? Fragmentation IPv6 pushes fragmentation onto the end-systems efficiency Header checksum

102 What is Missing from IPv4? Fragmentation IPv6 pushes fragmentation onto the end-systems efficiency Header checksum efficiency howdoesthechecksuminipv4behavewithrespecttothe time-to-live field?

103 What is Missing from IPv4? Fragmentation IPv6 pushes fragmentation onto the end-systems efficiency Header checksum efficiency howdoesthechecksuminipv4behavewithrespecttothe time-to-live field? thechecksummustberecomputedateveryhop,soipv6avoids that by getting rid of the checksum altogether

104 What is Missing from IPv4? Fragmentation IPv6 pushes fragmentation onto the end-systems efficiency Header checksum efficiency howdoesthechecksuminipv4behavewithrespecttothe time-to-live field? thechecksummustberecomputedateveryhop,soipv6avoids that by getting rid of the checksum altogether avoid redundancy: both link-layer protocols and transport protocols already provide error-detection features

105 What is Missing from IPv4? Fragmentation IPv6 pushes fragmentation onto the end-systems efficiency Header checksum efficiency howdoesthechecksuminipv4behavewithrespecttothe time-to-live field? thechecksummustberecomputedateveryhop,soipv6avoids that by getting rid of the checksum altogether avoid redundancy: both link-layer protocols and transport protocols already provide error-detection features Options

106 What is Missing from IPv4? Fragmentation IPv6 pushes fragmentation onto the end-systems efficiency Header checksum efficiency howdoesthechecksuminipv4behavewithrespecttothe time-to-live field? thechecksummustberecomputedateveryhop,soipv6avoids that by getting rid of the checksum altogether avoid redundancy: both link-layer protocols and transport protocols already provide error-detection features Options efficiency: a fixed-length header is easier to process

107 What is Missing from IPv4? Fragmentation IPv6 pushes fragmentation onto the end-systems efficiency Header checksum efficiency howdoesthechecksuminipv4behavewithrespecttothe time-to-live field? thechecksummustberecomputedateveryhop,soipv6avoids that by getting rid of the checksum altogether avoid redundancy: both link-layer protocols and transport protocols already provide error-detection features Options efficiency: a fixed-length header is easier to process better modularity for extensions and options

108 Higher-Level Protocol and Extensions

109 Higher-Level Protocol and Extensions 0 31 vers. traffic class flow label payload length next hdr hop limit source and destination addresses 40B

110 Higher-Level Protocol and Extensions 0 31 vers. traffic class payload length flow label TCP hop limit source and destination addresses 40B

111 Higher-Level Protocol and Extensions 0 31 vers. traffic class payload length flow label TCP hop limit source and destination addresses source port destination port sequence number acknowledgment number 40B...

112 Higher-Level Protocol and Extensions 0 31 vers. traffic class flow label payloadlength ext x hoplimit source and destination addresses 40B

113 Higher-Level Protocol and Extensions 0 31 vers. traffic class flow label payloadlength ext x hoplimit source and destination addresses next hdr next-hdr len 40B

114 Higher-Level Protocol and Extensions 0 31 vers. traffic class flow label payloadlength ext x hoplimit source and destination addresses TCP next-hdr len 40B source port destination port...