1. Information and Communication engineering (ICE) MUT ITEC4610 Network Switching and Routing ดร. ประวิทย์ ชุมชู หัวหน้าสาขาวิชาวิศวกรรมสารสนเทศและการสื่อสาร (ICE) MUT Email: prawit@mut.ac.thprawit@mut.ac.th ห้องทำงาน : F402 เบอร์โทรศัพท์ที่ทำงาน : (02)9883655 ต่อ 220 เบอร์โทรศัพท์เคลื่อนที่ : 065343850

2. Information and Communication engineering (ICE) MUT Class IX Multicasting ดร. ประวิทย์ ชุมชู หัวหน้าสาขาวิชาวิศวกรรมสารสนเทศและการสื่อสาร (ICE) MUT Email: prawit@mut.ac.thprawit@mut.ac.th ห้องทำงาน : F402 เบอร์โทรศัพท์ที่ทำงาน : (02)9883655 ต่อ 220 เบอร์โทรศัพท์เคลื่อนที่ : 065343850

3. Information and Communication engineering (ICE) MUT Multicasting  Multicast Applications Group Management ProtocolsGroup Management Protocols Multicast Routing Algorithm Multicast Routing Protocols

4. Information and Communication engineering (ICE) MUT Multicast Applications Software Distribution Replicated database update Command and control systems Audio/video conferencing Distributed games Distributed interactive simulation (DIS) Distribution of news Distance Learning

5. Information and Communication engineering (ICE) MUT Fundamental issues in multicast  Joining and leaving a group  Multicast sessions learning  Group members discovery  Dynamic group membership  Efficient transmission of multicast traffic  Resource optimization  Delivery tree maintenance  Time-sensitive delivery of multicast traffic  Data sequence maintenance  Synchronization

6. Information and Communication engineering (ICE) MUT Fundamental issues in multicast (Cont.)  Guaranteed arrival of multicast traffic  RTP  RMP  Scalability  Feedback implosions  The use of groups  Security  The exchange of cryptographic keys  UDP-based multicasting protocols

7. Information and Communication engineering (ICE) MUT Multicasting Multicast Applications  Group Management Protocols Multicast Routing Algorithm Multicast Routing Protocols

8. Information and Communication engineering (ICE) MUT Group Management Protocols IGMPv1 IGMPv2 IGMPv3

9. Information and Communication engineering (ICE) MUT IGMPv1(RFC1054)  Multicast router: periodically sends a query message to the all-hosts address (224.0.0.1)  A host sends a report in reply on a per grou basis, thereby refreshing the tentative states  IGMP v1 supports suppression for periodical refresh report messages.  IGMP v1 hosts send unsolicited reports upon joining a group, but leaves the group silently

10. Information and Communication engineering (ICE) MUT IGMPv2(RFC2236)  IGMP v2 maintains two types of query: general query and group-specific query;  Periodical refresh report suppression is supported as well.  The approach to lower leave latency

11. Information and Communication engineering (ICE) MUT IGMPv3(RFC 3376)  IGMP v3 maintains three types of query: general query, group-specific query, and group-and-source specific query  IGMP v3 maintains four reports: join, leave, state change, and refresh  No periodical refresh report suppression is supported  The approach to support source filtering: (group-id, filter mode, source list)

12. Information and Communication engineering (ICE) MUT Position of IGMP in the network layer

13. Information and Communication engineering (ICE) MUT IGMP is a protocol that manages group membership. The IGMP protocol gives the multicast routers information about the membership status of hosts (routers) connected to the network.. GROUP MANAGEMENT

14. Information and Communication engineering (ICE) MUT IGMP is a group management protocol. It helps a multicast router create and update a list of loyal members related to each router interface. Note:

15. Information and Communication engineering (ICE) MUT IGMP has three types of messages: the query, the membership report, and the leave report. There are two types of query messages, general and special. IGMP has three types of messages: the query, the membership report, and the leave report. There are two types of query messages, general and special. The topics discussed in this section include: Message Format IGMP MESSAGES

16. Information and Communication engineering (ICE) MUT IGMP message types

17. Information and Communication engineering (ICE) MUT IGMP message format

18. Information and Communication engineering (ICE) MUT IGMP type field

19. Information and Communication engineering (ICE) MUT A multicast router connected to a network has a list of multicast addresses of the groups with at least one loyal member in that network. For each group, there is one router that has the duty of distributing the multicast packets destined for that group. The topics discussed in this section include: Joining a Group Leaving a Group Monitoring Membership IGMP OPERATION

20. Information and Communication engineering (ICE) MUT IGMP operation

21. Information and Communication engineering (ICE) MUT Membership report

22. Information and Communication engineering (ICE) MUT In IGMP, a membership report is sent twice, one after the other. Note:

23. Information and Communication engineering (ICE) MUT Leave report

24. Information and Communication engineering (ICE) MUT The general query message does not define a particular group. Note:

25. Information and Communication engineering (ICE) MUT General query message

26. Information and Communication engineering (ICE) MUT Imagine there are three hosts in a network as shown in the following Figure See Next Slide A query message was received at time 0; the random delay time (in tenths of seconds) for each group is shown next to the group address. Show the sequence of report messages. Example 1

27. Information and Communication engineering (ICE) MUT Example 1

28. Information and Communication engineering (ICE) MUT Solution The events occur in this sequence: a. Time 12: The timer for 228.42.0.0 in host A expires and a membership report is sent, which is received by the router and every host including host B which cancels its timer for 228.42.0.0. b. Time 30: The timer for 225.14.0.0 in host A expires and a membership report is sent, which is received by the router and every host including host C which cancels its timer for 225.14.0.0. c. Time 50: The timer for 238.71.0.0 in host B expires and a membership report is sent, which is received by the router and every host. See Next Slide Example 1 (Continued)

29. Information and Communication engineering (ICE) MUT d. Time 70: The timer for 230.43.0.0 in host C expires and a membership report is sent, which is received by the router and every host including host A which cancels its timerfor 230.43.0.0. Note that if each host had sent a report for every group in its list, there would have been seven reports; with this strategy only four reports are sent. Example 1 (Continued)

30. Information and Communication engineering (ICE) MUT The IGMP message is encapsulated in an IP datagram, which is itself encapsulated in a frame. The topics discussed in this section include: IP Layer Data Link Layer Netstat Utility ENCAPSULATION

31. Information and Communication engineering (ICE) MUT Encapsulation of IGMP packet

32. Information and Communication engineering (ICE) MUT The IP packet that carries an IGMP packet has a value of 2 in its protocol field. Note:

33. Information and Communication engineering (ICE) MUT The IP packet that carries an IGMP packet has a value of 1 in its TTL field. Note:

34. Information and Communication engineering (ICE) MUT Destination IP addresses

35. Information and Communication engineering (ICE) MUT Mapping class D to Ethernet physical address

36. Information and Communication engineering (ICE) MUT An Ethernet multicast physical address is in the range 01:00:5E:00:00:00 to 01:00:5E:7F:FF:FF. Note:

37. Information and Communication engineering (ICE) MUT Change the multicast IP address 230.43.14.7 to an Ethernet multicast physical Solution We can do this in two steps: a. We write the rightmost 23 bits of the IP address in hexadecimal. This can be done by changing the rightmost 3 bytes to hexadecimal and then subtracting 8 from the leftmost digit if it is greater than or equal to 8. In our example, the result is 2B:0E:07. b. We add the result of part a to the starting Ethernet multicast address, which is (01:00:5E:00:00:00). The result is 01:00:5E:2B:0E:07 Example 2

38. Information and Communication engineering (ICE) MUT Change the multicast IP address 238.212.24.9 to an Ethernet multicast address. Solution a. The right-most three bytes in hexadecimal are D4:18:09. We need to subtract 8 from the leftmost digit, resulting in 54:18:09.. b. We add the result of part a to the Ethernet multicast starting address. The result is 01:00:5E:54:18:09 Example 3

39. Information and Communication engineering (ICE) MUT Tunneling For WAN, there is no physical multicast support

40. Information and Communication engineering (ICE) MUT We use netstat with three options, -n, -r, and -a. The -n option gives the numeric versions of IP addresses, the -r option gives the routing table, and the -a option gives all addresses (unicast and multicast). Note that we show only the fields relative to our discussion. $ netstat -nra Kernel IP routing table Destination Gateway Mask Flags Iface 153.18.16.0 0.0.0.0 255.255.240.0 U eth0 169.254.0.0 0.0.0.0 255.255.0.0 U eth0 127.0.0.0 0.0.0.0 255.0.0.0 U lo 224.0.0.0 0.0.0.0 224.0.0.0 U eth0 0.0.0.0 153.18.31.254 0.0.0.0 UG eth0 Any packet with a multicast address from 224.0.0.0 to 239.255.255.255 is masked and delivered to the Ethernet interface. Example 4

41. Information and Communication engineering (ICE) MUT We can show how IGMP can handle the sending and receiving of IGMP packets through our simplified version of an IGMP package. In our design an IGMP package involves a group table, a set of timers, and four software modules. The topics discussed in this section include: Group Table Timers Group-Joining Module Group-Leaving Module Input Module Output Module IGMP PACKAGE

42. Information and Communication engineering (ICE) MUT IGMP package

43. Information and Communication engineering (ICE) MUT Group table States: Free: There are no process left in the group Delaying: There is timer for for sending a report Idle: There is no timer Reference count: The number of process still interested in the group

44. Information and Communication engineering (ICE) MUT Group-Joining Module Receive: a request from a process to join a group 1.Look for the corresponding entry in the table 2.If (found) 1.Increment the reference count 3.If (not found) 1.Create an entry with reference count set one 2.Add the entry to the table 3.Request a membership report from the output module 4.Inform the data link layer to update its configuration table 4.Return

45. Information and Communication engineering (ICE) MUT Group-Leaving Module Receive: a request from a process to leave a group 1.Look for the corresponding entry in the table 2.If (found) 1.Decrease the reference count 2.If (reference count is zero) 1.If(any timer for this entry) 1.Cancel the timer 2.Change state to free 3.Request a leave report from the output module 3.Return

46. Information and Communication engineering (ICE) MUT Input Module Receive: an IGMP message 1.Check the message type 2.If (query) 1.Start a timer for each entry in the table with the state IDLE 2.Change each IDLE state to Delaying 3.Return 3.If (membership report) 1.Look for the corresponding entry in the table 2.If (found any state is Delaying) 1.Cancel the timer for the entry 2.Change the state to IDLE 4.Return

47. Information and Communication engineering (ICE) MUT Output Module Receive: a signal from a timer or a request from joining or leaving module 1.If the message comes from a timer 1.If (found and state is DELAYING) 1.Create a member ship report. 2.Reset the state to IDLE 2.If the message comes from the group-joining module 1.Create a membership report 3.If the message comes from the group-leaving module 1.Create a leave report 4.Send the message 5.Return

48. Information and Communication engineering (ICE) MUT Multicasting Multicast Applications Group Management ProtocolsGroup Management Protocols  Multicast Routing Algorithms Multicast Routing Protocols

49. Information and Communication engineering (ICE) MUT Multicast Routing algorithms Source-based tree –Multicast link state routing –Multicast Distance Vector routing Group-based tree

50. Information and Communication engineering (ICE) MUT Unicasting

51. Information and Communication engineering (ICE) MUT In unicasting, the router forwards the received packet through only one of its interfaces. Note:

52. Information and Communication engineering (ICE) MUT Multicasting

53. Information and Communication engineering (ICE) MUT In multicasting, the router may forward the received packet through several of its interfaces. Note:

54. Information and Communication engineering (ICE) MUT Multicasting versus multiple unicasting

55. Information and Communication engineering (ICE) MUT Emulation of multicasting through multiple unicasting is not efficient and may create long delays, particularly with a large group. Note:

56. Information and Communication engineering (ICE) MUT Multicasting has many applications today such as access to distributed databases, information dissemination, teleconferencing, and distance learning. The topics discussed in this section include: Access to Distributed Databases Information Dissemination Dissemination of News Teleconferencing Distance Learning Multicasting versus multiple unicasting

57. Information and Communication engineering (ICE) MUT In this section, we first discuss the idea of optimal routing, common in all multicast protocols. We then give an overview of multicast routing protocols. The topics discussed in this section include: Optimal Routing: Shortest Path Trees Routing Protocols MULTICAST ROUTING

58. Information and Communication engineering (ICE) MUT In unicast routing, each router in the domain has a table that defines a shortest path tree to possible destinations. Note:

59. Information and Communication engineering (ICE) MUT Shortest path tree in unicast routing

60. Information and Communication engineering (ICE) MUT In multicast routing, each involved router needs to construct a shortest path tree for each group. Note:

61. Information and Communication engineering (ICE) MUT In the source-based tree approach, each router needs to have one shortest path tree for each group. Note:

62. Information and Communication engineering (ICE) MUT Source-based tree approach

63. Information and Communication engineering (ICE) MUT Group-shared tree approach

64. Information and Communication engineering (ICE) MUT In the group-shared tree approach, only the core router, which has a shortest path tree for each group, is involved in multicasting. Note:

65. Information and Communication engineering (ICE) MUT Multicasting Multicast Applications Group Management ProtocolsGroup Management Protocols Multicast Routing Algorithm  Multicast Routing Protocols

66. Information and Communication engineering (ICE) MUT Taxonomy of common multicast protocols

67. Information and Communication engineering (ICE) MUT In this section, we briefly discuss multicast link state routing and its implementation in the Internet, MOSPF. The topics discussed in this section include: Multicast Link State Routing MOSPF MULTICAST LINK STATE ROUTING: MOSPF

68. Information and Communication engineering (ICE) MUT Multicast link state routing uses the source-based tree approach. Note:

69. Information and Communication engineering (ICE) MUT In this section, we briefly discuss multicast distance vector routing and its implementation in the Internet, DVMRP. The topics discussed in this section include: Multicast Distance Vector Routing DVMRP MULTICAST DISTANCE VECTOR: DVMRP

70. Information and Communication engineering (ICE) MUT Flooding broadcasts packets, but creates loops in the systems. Note:

71. Information and Communication engineering (ICE) MUT RPF eliminates the loop in the flooding process. Note:

72. Information and Communication engineering (ICE) MUT RPF

73. Information and Communication engineering (ICE) MUT Problem with RPF

74. Information and Communication engineering (ICE) MUT RPF versus RPB

75. Information and Communication engineering (ICE) MUT RPB creates a shortest path broadcast tree from the source to each destination. It guarantees that each destination receives one and only one copy of the packet. Note:

76. Information and Communication engineering (ICE) MUT RPF, RPB, and RPM

77. Information and Communication engineering (ICE) MUT RPM adds pruning and grafting to RPB to create a multicast shortest path tree that supports dynamic membership changes. Note:

78. Information and Communication engineering (ICE) MUT The Core-Based Tree (CBT) protocol is a group-shared protocol that uses a core as the root of the tree. The autonomous system is divided into regions and a core (center router or rendezvous router) is chosen for each region. The topics discussed in this section include: Formation of the Tree Sending Multicast Packets Selecting the Rendezvous Router CBT

79. Information and Communication engineering (ICE) MUT Group-shared tree with rendezvous router

80. Information and Communication engineering (ICE) MUT Sending a multicast packet to the rendezvous router

81. Information and Communication engineering (ICE) MUT In CBT, the source sends the multicast packet (encapsulated in a unicast packet) to the core router. The core router decapsulates the packet and forwards it to all interested interfaces. Note:

82. Information and Communication engineering (ICE) MUT Protocol Independent Multicast (PIM) is the name given to two independent multicast routing protocols: Protocol Independent Multicast, Dense Mode (PIM-DM) and Protocol Independent Multicast, Sparse Mode (PIM-SM). The topics discussed in this section include: PIM-DMPIM-SM PIM

83. Information and Communication engineering (ICE) MUT PIM-DM is used in a dense multicast environment, such as a LAN. Note:

84. Information and Communication engineering (ICE) MUT PIM-DM uses RPF and pruning/grafting strategies to handle multicasting. However, it is independent from the underlying unicast protocol. Note:

85. Information and Communication engineering (ICE) MUT PIM-SM is used in a sparse multicast environment such as a WAN. Note:

86. Information and Communication engineering (ICE) MUT PIM-SM is similar to CBT but uses a simpler procedure. Note:

87. Information and Communication engineering (ICE) MUT A multicast router may not find another multicast router in the neighborhood to forward the multicast packet. A solution for this problem is tunneling. We make a multicast backbone (MBONE) out of these isolated routers using the concept of tunneling. MBONE

88. Information and Communication engineering (ICE) MUT Logical tunneling

89. Information and Communication engineering (ICE) MUT MBONE

90. Information and Communication engineering (ICE) MUT Multicast Routing between Domains Multicast Source Discovery Protocol (MSDP) Border Gateway Multicast Protocol (BGMP)

91. Information and Communication engineering (ICE) MUT Summary Group Management Multicast Routing Algorithms Multicast Routing Protocols

92. Information and Communication engineering (ICE) MUT One more test LAN (Local Area Networks) ( Student Presentation, 26/08/2549) –Ethernet, Fast Ethernet, Gigabit Ethernet PPP (Point-to-Point) WANs( Student Presentation, 26/08/2549) –DSL, ADSL, VDSL, HDSL, SDSL –DATA Link layers (PPP, PPPoE) Switching and VLAN( Lecture X, 2/09/2549)