j.tiberghien - vub12-06-k.steenhaut & j.tiberghien - vub 1 telecommunications concepts chapter...
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J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB1
TelecommunicationsConcepts
Chapter 4.1
The Integration :
TCP/IP
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB2
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB3
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB4
The Internet & Transport Layer
Applications Layer
Internet Layer
Transport Layer
Networks Layer
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB5
The Internet Sublayer
• Modern data communications require connectivity through many different networks
• Existing networks offer diverse
– services levels (Connectionless/Connection Oriented)
– interfaces with transport layer
• An Interface layer (the INTERNET layer) is added on top of the Network layers
• The INTERNET layer ensures
– Uniform addressing through all networks
– Well defined and identical services from all networks
– A common interface with the Transport layer.
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB6
The Internet Sublayer
Design Philosophy• In the OSI Community : Less performing networks are enhanced
– Additional sublayer between network and internet layers : The Enhancement Sublayer.
– Most often, Connection oriented, Reliable.– Inspired by X25
• In the Internet Community (Internet Protocol): Minimal Internet Service definition
– Service restricted to whatever all networks can do : Connectionless, Unreliable– Inspired by Local Area Networks
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB7
The Internet Sublayer
OSI approachApplication 1 Application 2 Application 3
TP0-4
Internet Sublayeran
yn
etw
ork
Enh Enh Enh
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB8
The Internet Sublayer
IP approachApplication 1 Application 2 Application 3
TCP
Internet Protocolan
yn
etw
ork
UDP
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB9
Original IP Services
• Internet-wide uniform addressing.
– Two part addresses
» Network : identifies the network
» Host : identifies host on a specific network.
( Host part = subnet identifier + host identifier )
• Connectionless, unreliable datagram service
• Fragmentation when required by network
• Routing through the entire Internet.
• Elimination of “lost” datagrams
• Debugging facilities
• Special transmission modes
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB10
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB11
IP Networks
ISDN/PSTNLeased LineRouter LAN
WAN
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB12
Unicast
Unicast, Multicast and Broadcast
Multicast
Broadcast
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB15
Internet multicasting
• Distribute information to a group of selected users without overly taxing a networks’ resources
• Deliver ONE COPY of a datagram to all subnetworks to which group members are attached
• Definition of Multicast host group–Class D multicast addresses
• A mechanism to JOIN and LEAVE a multicast group– sender or receiver based control of group
membership–protocols to transmit and manage the group
membership info throughout the network
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB16
IP v4 addresses
Net/Host = all 0’s : Unknown address
Net/Host = all 1’s : Broadcast
0 Net (7) Host (24)Class A :
126 networks with up to 16 million hosts each
Four different address formats
10 Net (14) Host (16)Class B :
16382 networks with up to 65534 hosts each
110 Net (21) Host (8)Class C :
2 million networks with up to 254 hosts each
1110 Predefined Multicast groups(28)Class D :
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB17
IP v4 addresses
Some Examples0 Net (7) Host (24)Class A :
10 Net (14) Host (16)Class B :
110 Net (21) Host (8)Class C :
MIT... :
INFOS1 :
WWW.IEEE
xxxxxxxxxxx.10111000184.10101100172.
0001001018. 10000110134.11000111199.
xxxxxxxxxxx. 000000011.10001000136.
xxxxxxxxxxx 01111101125000000011
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB18
Routing in large networks
• Complete routing tables impossible in large networks
• Hierarchical routing is the solution
– Routing table restricted to one level of hierarchy
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB19
IP v4 Subnetting(example on Class C network 195.1.1)
• Host number can be split : Subnet + Host
• Length of actual host number given by mask
• MASK 11111111 11111111 11111111 11100000
• MASK 255 . 255 . 255 . 224
• Each subnet in example : 30 hosts (32 - 2)
Subnet number Addresses Broadcast address32 (001) 195.1.1.33 - 195.1.1.62 195.1.1.6364 (010) 195.1.1.65 - 195.1.1.94 195.1.1.9596 (011) 195.1.1.97 - 195.1.1.126 195.1.1.127
1 Network number Subnet1 0 Host
21 bits 3 bits 5 bits
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB20
IP v4 Subnetting ( Example : the 195.1.1.0 / 27 Network)
E F
CA B195.1.1.33/27 195.1.1.34/27 195.1.1.65/27
D195.1.1.66/27
195.1.1.97/27 195.1.1.98/27
To the Internet (Network 195.1.1.00)
Broadcast: 195.1.1.95Subnet : 195.1.1.64
Broadcast: 195.1.1.127Subnet : 195.1.1.96
Broadcast: 195.1.1.63Subnet : 195.1.1.32
Remark :In the notationxxx.xxx.xxx.xxx / nn gives the number of 1’s in the mask
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB21
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB22
IP v4 datagram format
IP header IP Data Area
Source IP Address
Destination IP Address
Options Padding
Header Checksum
Ident Frag.Offset
Total Length
TTL
Typ.Ser.
Fl.
Proto
Ver Len
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB23
IP v4 Header (1)
Source IP Address
Destination IP Address
Options Padding
Header Checksum
Ident Frag.Offset
Total Length
TTL
Typ.Ser.
Fl.
Proto
Ver Len
Ver : Protocol version, incompatible datagrams are rejected.
Len: Length of header, in 32 bit words.Tot.Length: Length, in bytes, of the entire datagram.
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB24
IP v4 Header (2)
Source IP Address
Destination IP Address
Options Padding
Header Checksum
Ident Frag.Offset
Total Length
TTL
Typ.Ser.
Fl.
Proto
Ver Len
Typ.Serv.: Precedence (0 = normal, 7 = control)D = Short delay wanted (best effort)T = High throughput wanted (best effort)R = High reliability wanted (best effort)
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB25
IP datagram fragmentation
IP header Fragment 2IP header Fragment 1
IP header IP Data Area
- Packet size exceeds maximum size in network- Excessive delay jitter due to long packets
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB26
IP v4 Header (3)
Source IP Address
Destination IP Address
Options Padding
Header Checksum
Ident Frag.Offset
Total Length
TTL
Typ.Ser.
Fl.
Proto
Ver Len
Ident : Unique identifier of fragmented datagram.Fl: “Do not fragment” bit.
“More fragments” bit.Frag.Offset: Offset of segment in original datagram.
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB27
IP v4 Header (4)
Source IP Address
Destination IP Address
Options Padding
Header Checksum
Ident Frag.Offset
Total Length
TTL
Typ.Ser.
Fl.
Proto
Ver Len
TTL : Time To Live (decremented at each node) Datagram discarded when TTL = 0.
Proto: Identifies the higher layer protocols.HdrCks: Redundant error detection bits for header.
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB28
IP v4 Header (5)
Source IP Address
Destination IP Address
Options(var. length) Padding
Header Checksum
Ident Frag.Offset
Total Length
TTL
Typ.Ser.
Fl.
Proto
Ver Len
Options : Debuging and special transmission modes copy : Option field reproduced in all fragments class : 0 = datagram or network control
2 = debuging and measurement number : specifies the function of the option
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB29
IP v4 Options
Class 0 Length
Option
– 1 : End of option list 1
– 2 : Security and handling restrictions 11
– 3 : Loose Source Routing var
– 7 : Record route var
– 9 : Strict Source Routing var
Class 2Option
– 4 : Internet timestamp var
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB30
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB31
Routing• Routing = transmission of a datagram
– from a “source IP address”
– to a “destination IP address”
• Direct Routing
– Current and destination addresses on same network
– Direct delivery to destination
• Indirect Routing
– Current and destination addresses on different networks
– Datagram forwarded from source to destination via routers
– Routers have an address in at least two networks
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB32
IP Networks
Router1.2
1.4
1.3 1.1
2.1
3.3
3.24.1
4.3
4.2
5.2
2.2
2.3
6.1
6.2
5.35.1
7.17.2
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB33
Routing
IF destination net is directly connected
THEN (* Direct Routing *)
encapsulate datagram in network frame;
send frame to destination;
ELSE (* Indirect Routing *)
with “destination net” as index in local routing table, find address of local router appropriate for reaching that net;
encapsulate datagram in network frame;
send frame to selected local router;
END (* IF *)
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB34
IP Networks
1.2
1.4
1.3 1.1
2.1
3.3
3.24.1
4.3
4.2
5.2
2.2
6.1
6.2
5.35.1
7.17.2
1.2 > 7.2
2.3
Dest.net Forw.to
direct1.1
1#1
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB35
IP Networks
1.2
1.4
1.3 1.1
2.1
3.3
3.24.1
4.3
4.2
5.2
2.2
6.1
6.2
5.35.1
7.17.2
2.3
Dest.net Forw.to
direct3.22.2
1,2,34
>4
1.2 > 7.2
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB36
IP Networks
1.2
1.4
1.3 1.1
2.1
3.3
3.24.1
4.3
4.2
5.2
2.2
6.1
6.2
5.35.1
7.17.2
1.2 > 7.2
2.3
Dest.net Forw.to
direct2.15.3
2,5,61,3,4
7
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB37
IP Networks
1.2
1.4
1.3 1.1
2.1
3.3
3.24.1
4.3
4.2
5.2
2.2
6.1
6.2
5.35.1
7.17.2
1.2 > 7.2
2.3
Dest.net Forw.to
direct5.25.1
5,71,3,42,6
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB38
IP Networks
1.2
1.4
1.3 1.1
2.1
3.3
3.24.1
4.3
4.2
5.2
2.2
6.1
6.2
5.35.1
7.17.2
7.2 > 1.2
2.3
Dest.net Forw.to
direct7.1
7#7
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB39
IP Networks
1.2
1.4
1.3 1.1
2.1
3.3
3.24.1
4.3
4.2
5.2
2.2
6.1
6.2
5.35.1
7.17.2
7.2 > 1.2
2.3
Dest.net Forw.to
direct5.25.1
5,71,3,42,6
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB40
IP Networks
1.2
1.4
1.3 1.1
2.1
3.3
3.24.1
4.3
4.2
5.2
2.2
6.1
6.2
5.35.1
7.17.2
7.2 > 1.2
2.3
Dest.net Forw.to
direct3.35.1
3,4,51,26,7
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB41
IP Networks
1.2
1.4
1.3 1.1
2.1
3.3
3.24.1
4.3
4.2
5.2
2.2
6.1
6.2
5.35.1
7.17.2
7.2 > 1.2
2.3
Dest.net Forw.to
direct3.22.2
1,2,34
>4
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB42
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB43
Classless InterDomain Routing
• Problems with class based addressing : – Too few Class B networks. – Class C networks too small
• Obvious solution :– Multiple Class C addresses for single network
• But…– All routers should know all networks
– Over 10 6 class C networks possible !
0 Net (7) Host (24)Class A :
10 Net (14) Host (16)Class B :
110 Net (21) Host (8)Class C :
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB44
Classless InterDomain Routing
0 Net (7) Host (24)Class A :
10 Net (14) Host (16)Class B :
110 Net (21) Host (8)Class C :
MIT... :
INFOS1 :
WWW.IEEE
Belnet
xxxxxxxxxxx.10111000184.10101100172.10111110190.
0001001018. 10000110134.11000111199.11000001193.
xxxxxxxxxxx. 000000011.10001000136.xxxxxxxxxxx.
xxxxxxxxxxx 01111101125000000011xxxxxxxxxxx
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB45
Classless InterDomain Routing
Techniques to limit size of router tables:
• Replace classes by variable sized networks :
– associate with each network number a mask.
– mask defines network size.
– Router tables contain network number & mask
• Assign new addresses on a geographical basis :
– Europe : 194.0.0.0 to 195.255.255.255
– N.America : 198.0.0.0 to 199.255.255.255
– S.& C.America : 200.0.0.0 to 201.255.255.255
– Asia : 202.0.0.0 to 203.255.255.255
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB46
Classless InterDomain Routing
Examples of address assignment: • User X : 2048 addresses, 194.24.0.0 to 194.24.7.255
– Addr = 11000010 00011000 00000XXX XXXXXXXX– Mask = 11111111 11111111 11111000 00000000
• User Y : 4096 addresses, 194.24.16.0 to 194.24.31.255– Addr = 11000010 00011000 0001XXXX XXXXXXXX– Mask = 11111111 11111111 11110000 00000000
• User Z : 1024 addresses, 194.24.8.0 to 194.24.11.255– Addr = 11000010 00011000 000010XX XXXXXXXX– Mask = 11111111 11111111 11111100 00000000
• Unknown address : 194.24.17.4– X : 11000010 00011000 00010001 00000100– y : 11000010 00011000 00010001 00000100– z : 11000010 00011000 00010001 00000100
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB47
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB48
Internet Control Message Protocol
Specific messages exchanged by routers to
– Report errors
» Destination unreachable
» Time to live exceeded
» Invalid header field
» …
– Explore and reconfigure network
» Request echo / Answer echo request
» Request timestamp / Answer timestamp request
» Redirect routes
» …
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB49
ICMP error messages
Tr. header Transport data area
IP header ICMP error message
IP header IP Data Area
Error causing IP packet
Error reporting ICMP packet
IP header Tr. header
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB50
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB51
The Internet & Transport Layer
Applications Layer
Internet Layer
Transport Layer
Networks Layer
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB52
The Transport Layer
is an end to end service
Appl. Appl.
Transp. Transp.
Netw. Netw.
Host A Host B
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB53
QOS and the Transport Layer
Transport Layer
Connection Oriented / Connectionless Transport Servicewith specified Quality of Service
Connection Oriented / Connectionless Network Servicewith Quality of Service imposed by technology
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB54
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB55
Transport Control Protocol
• Service offered to application layer :– Application port identification– Stream of bytes is transferred between applications– Connection oriented full-duplex communication– Data-stream decomposed in sequence of data
segments– Error correction with sliding window algorithm– Best effort congestion control >> No guaranteed delays
• Service required from network layer :– Connectionless network service (As provided by the Internet Protocol)
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB56
TCP segment format
TCP header TCP Data Area
Source Port Destination Port
Window Size
Checksum
Sequence Number
Acknowledgment Number
Urgent Pointer
Off. | Res. | Code
paddingOptions
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB57
TCP Error Correction• Sliding window error correction
• Cumulative Acknowledgment– Position in stream of last received byte– Acknowledgments piggybacking with reverse traffic– Retransmission policy implementation dependent
• Adaptive time-out– Network delays vary widely due to traffic fluctuations– Round-trip time continuously monitored– Time-out based on weighted average of round-trip times
• Congestion control– Receiver congestion prevented by adapting window size – Network congestion detected by round-trip delay analysis– Congestion cured by slowing down transmissions
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB58
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB59
User Datagram Protocol
• Service offered to application layer :–Application port identification
–Connectionless (stateless)
–Error detection, no correction
• Service required from network layer :–Connectionless network service
(As provided by the Internet Protocol)
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB60
UDP message format
UDP header UDP Data Area
Source Port Destination Port
UDP ChecksumLength
• Destination Port : Application identifier• Source Port : 0 or port for answering• Length : in bytes, inclusive the header 0 <= DataLength <= 65,527 bytes• Checksum : Redundant bits for error detection
UDP header : 8 bytes
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB61
UDP Port Numbers(some examples)
• 0 Reserved
• 7 Echo
• 11 Users (Gives list of active users)
• 13 Daytime
• 17 Quote (Gives the quote of the day)
• 53 Domain (Domain name server)
• 67 BOOTPS (Bootstrap Protocol Server)
• 68 BOOTPC (Bootstrap Protocol Client)
• 69 TFTP (Trivial File Transfer Protocol)
• 123 NTP (Network Time Protocol)
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB62
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB63
Network Address Translation
Internet
192.168.1.10
192.168.1.11
192.168.1.12
NAT
134.184.23.112
intranet
TCP and UDP port numbers are abused to
identify the hosts on the intranet.
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB64
Network Address Translation
• Work-around for solving IPv4 address shortage.• Maps many intranet addresses into a single internet
address.• Uses TCP or UDP non standard port numbers to identify
hosts in the intranet.• A NAT device can not be stateless and therefore is a
reliability threat.• NAT devices are not transparent to transport protocols
different from TCP or UDP.• NAT devices jeopardize peer to peer applications • Is believed by some to increase intranet security• Is a good excuse for further delaying IPv6 deployment
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB65
Contents
• The internet concept• Version 4 Internet Protocols
– IP addressing– IP headers– CIDR– ICMP
• The transport layer– The Transmission Control Protocol– The User Datagram Protocol
• Network Address Translation• Version 6 Internet Protocol• Side track : IP routing
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB66
IP Next
Generation• Reasons to change IP
– Insufficient address space.
– No effective QOS guarantees
– No practical support for secure communications
– No good support for multicasting
• Constraints on any successor to IP– Upward compatibility with IPv4
– Not significantly less efficient than IPv4
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB67
IP ng = IPV6
• 2128 instead of 232 possible addresses
– Upward compatible with IP v4 addresses
– New “anycast” addressing mode
– Provisions for more efficient multicasting
– Provisions for addresses of other protocols
• Provisions for QOS specification
• More efficient header format
– Little used fields removed
– Options handled through extension header
• Security
– Authentication
– Data integrity
– Confidentiality
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB68
IP v4 datagram format
IP header IP Data Area
Source IP Address
Destination IP Address
Options Padding
Header Checksum
Ident Frag.Offset
Total Length
TTL
Typ.Ser.
Fl.
Proto
Ver Len
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB69
IP v6 Header (1)
Source IP Address
Destination IP Address
Payload Length
Flow Label
Next Hdr Hop Lim.
Ver Pri
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB70
IP v6 Addresses128 bit addresses = 7. 1023 addresses / m2 on the earth !
Prefix Allocation Fraction
0000 001 NSAP 1/128 (0.8%)0000 010 IPX 1/128 (0.8%)001 Global unicast 1/8 (12.5%)010 Provider unicast 1/8 (12.5%)100 Geographic unicast 1/8 (12.5%)1111 1110 1 Local use addresses 1/512 (0.2%)1111 1111 Multicast groups 1/256 (0.4%)
Represented as 8 groups of 4 hex digits, separated by colons, leading zeros suppressed:
21DA:D3:0:2F3B:2AA:FF:FE28:9C5A
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB71
IP v6 Unicast AddressesHierarchical addresses to facilitate routing.
001 INTresTLA SLANLA
3 13 8 24 18 64
TLA: Top level aggregation identifier (global ISP’s)NLA: Next level aggregation identifier (within ISP)res: reserve bits to be added to TLA or NLA in futureSLA: Site level aggregation identifier (local subnet)INT: Interface identifier on a specific subnet
(equivalent to v4 host identifier, but now, a singlecomputer can have several interfaces)
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB73
IP v6 Header (2)
Source IP Address
Destination IP Address
Payload Length
Flow Label
Next Hdr Hop Lim.
Ver Pri
Flow controlled traffic (TCP) : 0 - 71 = filler traffic (NetNews, ...)4 = attended bulk transfer (FTP, HTTP, ...)6 = Interactive traffic (Telnet, X, ...)7 = Internet control traffic (routing, SNMP, ...)
Traffic without flow control (UDP) : 8 - 15Real time video and audio, ...
Priority : a step towards QOS control
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB74
IP v6 Header (3)
Source IP Address
Destination IP Address
Payload Length
Flow Label
Next Hdr Hop Lim.
Ver Pri
Flow = connection oriented communicationimplemented through connectionless service
Flow uniquely identified bysource addressflow label
Future routers could reserve resources for flows
Flow Label : an other step towards QOS control
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB75
BibliographyTo know More about
IPngScott o. Bradner, Allison Mankin
IPng
Internet Protocol Next Generation
Addison-Wesley Publishing Company,1996.
ISBN 0-201-63395-7 Available in the VUB Library :
ESP
681.30
G
BRAD
96
J.Tiberghien - VUB12-06-K.Steenhaut & J.Tiberghien - VUB76
Further Readings on the INTERNET
– The INTERNET Book, 4th edition 2007. Everything you need to know about computer networking and how the
Internet works ISBN 0-13-233553-0– Internetworking with TCP/IP, Volume I, 5th edition, 2006. Principles, Protocols and Architecture ISBN 0-13-187671-6– Internetworking with TCP/IP, Volume II, 3rd edition, 1999. Design, Implementation, and Internals (with D.Stevens) ISBN 0-13-973843-6– Internetworking with TCP/IP, Volume III, 2000. Client-Server Programming and Applications,
Linux/POSIX Socket Version (with D.Stevens) ISBN 0-13-032071-4
By Douglas E. COMERPublished by Prentice Hall International Editions
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