Basic ip and networking ver 3 kl

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Basic ip and networking ver 3 kl

  1. 1. 11 BASIC IP NETWORKING Kuala Lumpur January 2011 Azhar Ali
  2. 2. 22 TCP/IP FUNDAMENTALS
  3. 3. 33 • TCP/IP is the first set of protocols used in Internet • Allows computers to communicate / share resources across a network • Work on TCP/IP started in 1970s  Funded by US Military  Advanced Research Project Agency (ARPA)  Network protocols of ARPANET were upgraded I N T R O
  4. 4. 44 TCP/IP technology TCP/IP and the Internet  Used as a standard  To bridge the gap between non- compatible platforms  All computers connected to the Internet understands TCP/IP
  5. 5. 55 In 1978, International Standards Organization (ISO) proposed a 7-layer reference model for network Services and protocols Network Layering in TCP/IP 7 6 5 4 3 2 1
  6. 6. 66 7 6 5 4 3 2 1 • To provide well-defined interfaces between adjacent layers  A change in one layer does not affect the other layers  Interface must remain the same • Allows a structured development of network software Why Layering ?
  7. 7. 77 The 7-layer OSI Model OSI Model shows how networking should work- provides a blueprint for protocols to follow – but it’s not mandatory Most protocols do follow OSI model OSI model can help learn how networking works, and how to troubleshoot network problems Application Presentation Session Transport Network Datalink Physical 7 6 5 4 3 2 1
  8. 8. 88 The TCP/IP Protocol 4-layer Model De-facto standard – used for connection to the Internet and within most networks Uses a 4 layer model Covers most of the popular protocols used daily in network communications Application Transport Internet Network
  9. 9. 99 4 on 7-layer Model TCP/IP OSI
  10. 10. 1010 7-layer Model Summary OSI Model Data Unit Layer Function Host Layers Data 7 Application Network process to application 6 Presentation Data representation, encryption and decryption 5 Session Interhost communication Segments 4 Transport End-to-end connections and reliability, flow control Network Layers Packet 3 Network Path determination and logical addressing Frame 2 Data Link Physical addressing Bit 1 Physical Media, signal and binary transmission
  11. 11. 1111 • Refers to a family of protocols • The protocols are built on top of connectionless technology TCP/IP Protocol Suite  Data sent from one node to another as a sequence of datagrams  Each datagram sent independently  The datagrams corresponding to the same message may follow different routes o Variable delay, arrival order at destination
  12. 12. 1212 Data Flow in 4-layer Model Application Transport Internet Network Application Transport Internet Network Internet Network ‘network’ PHYSICAL PHYSICAL A C B
  13. 13. 1313 TCP/IP Family Members FTP TFTP SMTP SNMP DNS USER PROCESS .. TRANSMISSION CONTROL PROTOCOL (TCP) USER DATAGRAM PROTOCOL (UDP) INTERNET PROTOCOL (IP) ICMP IGMP ARP RARP Datalink and Hardware Layer e.g Ethernet 4 3 2 1
  14. 14. 1414 Typical Scenario User Process User Process TCP UDP IP Datalink and Hardware Layer e.g Ethernet 4 3 2 1
  15. 15. 1515 4 and 7-layer Model Comparison Reference : http://www.lex-con.com/protocols/ip.htm
  16. 16. 1616 7-layer Map – TCP/IP
  17. 17. 1717 IP transports datagrams (packets) from the source node to the destination node  Responsible for routing the packets  Breaks a packet into smaller packets, if required  Unreliable service o A packet may be lost in transit o Packets may arrive out of order o Duplicate packets may be generated What does IP do?
  18. 18. 1818 • TCP provides a connection- oriented, reliable service for sending messages  Split a message into packets  Reassemble packets at destination  Resend packets that were lost in transit • Interface with IP  Each packet forwarded to IP for delivery  Error control is done by TCP What does TCP do?
  19. 19. 1919 • UDP provides a connectionless, unreliable service for sending datagrams (packets)  Messages small enough to fit in a packet (e.g., DNS query)  Simpler (and faster) than TCP  Never split data into multiple packets  Does not care about error control • Interface with IP  Each UDP packet send to IP for delivery What does UDP do?
  20. 20. 2020 Addresses in TCP/IP User Process User Process TCP UDP IP Datalink and Hardware Layer e.g Ethernet 4 3 2 1 Internet Address (32 bits) Port Address (16 bits) Physical Address (48 bits)
  21. 21. 2121 Encapsulation Basic concept  As data flows down the protocol hierarchy, headers (and trailers) get appended to it  As data moves up the hierarchy, headers (and trailers) get stripped off
  22. 22. 2222 TFTP over Ethernet TFTP client UDP IP Ethernet TFTP server UDP IP Ethernet
  23. 23. 2323 Encapsulation in TFTP Data Data Data Data Data H-TFTP H-TFTP H-TFTP H-TFTP H-UDP H-UDP H-UDP H-IP H-IPH-ETH T-ETH TFTP message UDP segment IP packet Ethernet frame 14 20 8 4 200 4 H – Header T – Trailer
  24. 24. 2424 DATAGRAM
  25. 25. 2525 • IP layer provides a connectionless, unreliable delivery system for packets …………..….. mentioned before • Each packet is independent of one another  IP layer need not maintain any history  Each IP packet must contain the source and destination addresses The IP Layer
  26. 26. 2626 • IP layer does not guarantee delivery of packets • IP layer encapsulation  Receives a data chunk from the higher layer (TCP or UDP)  Prepends a header of minimum 20 bytes o Containing relevant information for handling routing and flow control The IP Layer (contd)
  27. 27. 2727 Format of IP Datagram Header VER HLEN Service type Total Length Identification Flags Fragment Offset Time to Live Protocol Header Checksum Source IP Address Destination IP Address Options DATA 0 4 8 1516 31
  28. 28. 2828 IP Header Fields Fields No of bits Remarks VER 4 Version of the IP protocol in use (typically 4) HLEN 4 • Length of the header, expressed as the number of 32-bit words • Minimum size is 5, and maximum 15 Total Length 16 • Length in bytes of the datagram, including headers • Maximum datagram size : 2 = 65536 bytes Service Type 8 • Allow packet to be assigned a priority • Router can use this field to route packets • Not universally used Time to Live 8 • Prevents a packet from travelling in a loop • Senders sets a value, that is decremented at each hop. If it reaches zero, packet is discarded Protocol 8 Identifies the higher layer protocol being used 16
  29. 29. 2929 IP Header Fields (contd) Fields No of bits Remarks Source IP address 32 Internet address of the sender Destination IP address 32 Internet address of the destination Identification, Flags, Fragment Offset 32 Used for handling fragmentation Options var • Can be given provided router supports • Source routing, for example Header Checksum 16 •Covers only the IP header •A mismatch in checksum causes the datagram to be discarded
  30. 30. 3030
  31. 31. 3131 1. How many bits are there in the IP address? 2. How many bits are there in the Ethernet address? 3. What does the Ethernet address signify? 4. What does the IP address signify? 5. What does the port number signify?
  32. 32. 3232 6. What the various layers in the simplified TCP/IP protocol stack corresponds to with respect to the OSI 7-layer model? 7. Why is the transport layer called end-to-end or host-to-host layer? 8. IP is unreliable, and TCP uses IP. How does TCP provide reliable service to the application layer? 9. List two common applications that use UDP.
  33. 33. 3333 10. Why is the IP protocol considered unreliable? 11. What does TCP do if the message to be sent is larger than what a single datagram can handle? 12. What is the purpose of the ‘Time to Live’ field in the IP header? 13. What is the maximum size of data that can be accommodated in an IP datagram?
  34. 34. 3434 Basic IP Addressing • Each host connected to the Internet is identified by a unique IP address • An IP address is a 32 bit quantity  Expressed as dotted- decimal notation w.x.y.z, where dots are used to separate each of the four octets of the address  Consists of two logical parts: o A network number o A host number • The partition defines the IP address classes
  35. 35. 3535 Dotted Decimal Notation (w.x.y.z) 66.134.48.126 01000010.10001000.00110000.01111110 32 bits An IP address for an Internet site would look like this
  36. 36. 3636 Hierarchical Addressing A computer on the Internet is addressed using two method:  The network number o Assigned and managed by central authority  The host number o Assigned and managed by local network administrator When routing a packet to the Destination, only the network number is looked at
  37. 37. 3737 IP Address Classes There are five defined IP Address Classes Class A, B, C, D and E (reserved) identified by the first few bits in the IP address There are also exists some special-purpose IP addresses
  38. 38. 3838 IP Address Classes The class-based addressing is also known as the classful model  Different network classes represent different network- to-hosts ratio  Lend themselves to different network configurations
  39. 39. 3939 IP Address Classes Class Network Address A 10.0.0.0 through 10.255.255.255 B 172.16.0.0 through 172.31.255.255 C 192.168.0.0 through 192.168.255.255 Class First Bits First Byte Values Network ID Bits Host ID Bits Number of Networks Number of Hosts A 0 1 - 126 7 24 126 16,777,214 B 10 128 -191 14 16 16,384 65,534 C 110 192 - 223 21 8 2,097,152 254 Private IP Address Range – Special purpose
  40. 40. 4040 IP Subnetting • Subset of a class A, B or C network • Introduce third level of hierarchy  A network portion  A subnet portion  A host portion • Uses network masks
  41. 41. 4141 Network Masks Network mask 255.0.0.0 is applied to a class A network 10.0.0.0 11111111 00000000 00000000 00000000 In binary, the mask is a series of contiguous 1’s followed by a series of contiguous 0’s Network Host
  42. 42. 4242 Network Masks • Class A network 10.5.0.20 00001010 00000101 00000000 00010100 11111111 11111111 00000000 00000000 10.5.0.20 255.255.0.0 IP Address Mask Network HostSubnet
  43. 43. 4343 Network Masks e.g Network mask of 255.255.255.0 Subnet 255.255.255.X X X (in binary) No. of Subnets No. of Hosts 128 1000 0000 2 128 192 1100 0000 4 64 224 1110 0000 8 32 240 1111 0000 16 16 248 1111 1000 32 8 252 1111 1100 64 4
  44. 44. 4444 Running out of IP addresses • Growing demand for IP addresses  Severe strain on the classful model  Due to wastage of address space • Measure taken  Creative allocation of IP addresses  Classless Inter-Domain Routing (CIDR) o e.g 144.16.192.57/18  Private IP addresses, and Network Address Translation (NAT)  IP v6
  45. 45. 4545
  46. 46. 4646 1. Change the following IP address from binary notation to dotted decimal notation 11000100 10001111 00110000 10000001 2. Find the error if any in the following IP address: 144.15.256.7 3. Find the class of the following IP address: 227.15.75.111? 4. Given the network address 135.75.0.0, find the class, the network id, and the range of the addresses 5. What do the following IP address signify: 144.16.255.255
  47. 47. 4747 BASIC NETWORK
  48. 48. 4848 Common Component in IP Network
  49. 49. 4949

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