1. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 1 IP Multicasting: Explaining Multicast

2. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 2 Objectives  Describe the IP multicast group.  Compare and contrast Unicast packets and multicast packets.  List the advantages and disadvantages of multicast traffic.  Discuss two types of multicast applications.  Describe the types of IP multicast addresses.  Describe how receivers can learn about a scheduled multicast session.

3. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 3 Multicast Overview

4. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 4 IP Multicast Distribute information to large audiences over an IP network

5. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 5 Multicast Adoption Past, Present, and Future Multicast (1986-2005) 19921996199719982000200120022003200420051986 Time Early Adopters NASA, DOD, Cisco, Microsoft, Sprint Financials NASDAQ, NYSE, LIFE, Morgan, GS, Prudential E Learning 150 Universities in US, Hawaii, Oregon, USC, UCLA, Berkley Corporate Communication HP, IBM, Intel, Ford, BMW, Dupont MXU & Content Providers Fastweb, B2, Yahoo, BBC, CNN Multicast Deployment z z z Research Community MBONE Surveillance Law Enforcement and Federal IPv6 Multicast NTT, Sony, Panasonic, Multicast VPN C&W, MCI, AT&T, TI, FT, DT, NTT

6. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 6 Why Multicast?  Used when sending same data to multiple receivers  Better bandwidth utilization  Less host/router processing  Used when addresses of receivers unknown  Used when simultaneous delivery for a group of receivers is required (simulcast)

7. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 7 Unicast vs. Multicast

8. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 8 Multicast Advantages Enhanced efficiency: Controls network traffic and reduces server and CPU loads Optimized performance: Eliminates traffic redundancy Distributed applications: Makes multipoint applications possible

9. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 9 Other Multicast Advantages  For the equivalent amount of multicast traffic, the sender needs much less processing power and bandwidth.  Multicast packets do not impose as high a rate of bandwidth utilization as unicast packets, so there is a greater possibility that they will arrive almost simultaneously at the receivers.

10. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 10 Multicast Disadvantages Multicast is UDP-based.  Best-effort delivery Heavy drops in Voice traffic Moderate to Heavy drops in Video  No congestion avoidance  Duplicate packets may be generated  Out-of-sequence delivery may occur  Efficiency issues in filtering and in security

11. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 11 Types of Multicast Applications One-to-many  A single host sending to two or more (n) receivers Many-to-many  Any number of hosts sending to the same multicast group; hosts are also members of the group (sender = receiver) Many-to-one  Any number of receivers sending data back to a source (via unicast or multicast)

12. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 12 Corporate Broadcasts Distance Learning Training Videoconferencing Whiteboard/Collaboration Multicast File Transfer Data and File Replication Real-Time Data Delivery—Financial Video-on-Demand Live TV and Radio Broadcast to the Desktop IP Multicast Applications

13. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 13 Self Check 1.List some advantages of multicast transmission over unicast transmission. 2.How does the best effort delivery nature of UDP impact multicast transmissions? 3.What are the 3 basic types of multicast applications? 4.Give examples of one-to-many. 5.What model is used when a host can be a sender as well as a receiver simultaneously?

14. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 14 Multicast Addressing

15. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 15 IP Multicast Address Structure IP group addresses:  Class D address (high-order three bits are set)  Range from 224.0.0.0 through 239.255.255.255

16. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 16 Multicast Addressing IPv4 Header OptionsPadding Time to LiveProtocolHeader Checksum IdentificationFlagsFragment Offset VersionIHLType of ServiceTotal Length Source Address Destination Address Destination Source Source Address can never be Class D Multicast Group Address 224.0.0.0 - 239.255.255.255 (Class D) Multicast Group Address Range Destination 1.0.0.0 - 223.255.255.255 (Class A, B, C) Source

17. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 17 IP Multicast Address Groups  Local scope addresses 224.0.0.0 to 224.0.0.255  Global scope addresses 224.0.1.0 to 238.255.255.255  Administratively scoped addresses 239.0.0.0 to 239.255.255.255

18. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 18 Local Scope Addresses Well-known addresses assigned by IANA  Reserved use: 224.0.0.0 through 224.0.0.255 224.0.0.1 (all multicast systems on subnet) 224.0.0.2 (all routers on subnet) 224.0.0.4 (all DVMRP routers) 224.0.0.13 (all PIMv2 routers) 224.0.0.5, 224.0.0.6, 224.0.0.9, and 224.0.0.10 used by unicast routing protocols

19. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 19 Global Scope Addresses  Transient addresses, assigned and reclaimed dynamically (within applications): Global range: 224.0.1.0-238.255.255.255 224.2.X.X usually used in MBONE applications  Part of a global scope recently used for new protocols and temporary usage

20. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 20 Administratively Scoped Addresses Transient addresses, assigned and reclaimed dynamically (within applications):  Limited (local) scope: 239.0.0.0/8 for private IP multicast addresses (RFC-2365) Site-local scope: 239.255.0.0/16 Organization-local scope: 239.192.0.0 to 239.251.255.255

21. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 21 Layer 2 Multicast Addressing IEEE 802.3 MAC Address Format

22. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 22 IANA Ethernet MAC Address Range 01-00-5e-00-00-00 through 01-00-5e-7f-ff-ff Available range of MAC addresses for IP multicast

23. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 23 00000001:00000000:01011110:00000000:00000000:00000000 IANA Ethernet MAC Address Range through  Within this range, these MAC addresses have the first 25 bits in common.  The remaining 23 bits are available for mapping to the lower 23 bits of the IP multicast group address. Available range of MAC addresses for IP multicast 00000001:00000000:01011110:01111111:11111111:11111111

24. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 24 Ethernet MAC Address Mapping

25. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 25 224.1.1.1 224.129.1.1 225.1.1.1 225.129.1.1. 238.1.1.1 238.129.1.1 239.1.1.1 239.129.1.1 0x0100.5E01.0101 1 - Multicast MAC Address (FDDI and Ethernet) 32 - IP Multicast Addresses Multicast Addressing Be Aware of the 32:1 Address Overlap IP Multicast MAC Address Mapping (FDDI & Ethernet)

26. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 26 Madcap in MS Server

27. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 27 How are Multicast Addresses Assigned? Static Global Group Address Assignment  Temporary method to meet immediate needs  Group range: 233.0.0.0 – 233.255.255.255 Your AS number is inserted in middle two octets Remaining low-order octet used for group assignment  Defined in RFC 2770 “GLOP Addressing in 233/8” Manual address allocation by the admin is still the most common practice.

28. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 28 Learning About Multicast Sessions Potential receivers have to learn about multicast streams or sessions available before a multicast application is launched. Possibilities:  Another multicast application sending to a well-known group whose members are all potential receivers  Directory services  Web page, e-mail  Session Announcement Protocol (SAP)

29. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 29 sdr—Session Directory

30. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 30 A Cisco IP/TV Example Cisco IP/TV application  Clients (viewers) use program listing Contact the server directly Listen to SAP announcements

31. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 31 Self Check 1.What is the address range for multicast addresses? 2.What are Local Scope Addresses? 3.What is Mbone? 4.What is the 32-to-1 overlap? 5.What is MADCAP?

32. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 32 Summary  IP multicast is a much more efficient means of delivering content where a single sender needs to deliver the content to multiple receivers. This task may be achieved through the use of multicast groups.  IP multicasts are designated by the use of a specific Class D IP address range. This is achieved through global scope addresses, which are assigned dynamically, and administratively scoped, which are assigned locally and are reserved for use inside private domains.

33. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 33 Q and A

34. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 34 Resources  Wikipedia IP Multicast article http://en.wikipedia.org/wiki/IP_Multicast  Webopedia Mbone article http://www.webopedia.com/TERM/M/Mbone.html

35. © 2006 Cisco Systems, Inc. All rights reserved.Cisco Public BSCI Module 7 Lesson 1 35