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Multicasting
AbdulRahman AbdulSalam
Ahmad AlHammar
Yousef Yateem
Types of Casting
1. Unicasting:
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One-to-one
Easy to implement
Will waste bandwidth if many people demand the same
data.
2. Broadcasting:
3. Multicasting:
Unicasting
Types of Casting
1. Unicasting:
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One-to-one
Easy to implement
Will waste bandwidth if many people demand the same
data.
2. Broadcasting:
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One-to-all
Good when all request the same data
Bad if some don’t want it
3. Multicasting:
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One-to-group
Solves both the problems above
More complicated than the two above
Multicasting
The Basic Idea of Multicasting
Instead of sending a separate copy
of the data for each recipient, the source
sends the data only once, and routers
along the way to the destinations
make copies as needed.
Why Multicasting?
• Conserves Bandwidth
• Consider stats from Victoria Secrets
• More than 1 million web hits during the 1st hour
• 283% increase in web traffic during event.
• Enhanced Efficiency:
• controls network traffic and reduces CPU loads
• Optimized performance:
• eliminates traffic redundancy
• It’s all about the Cost
• more bandwidth  more costs
Multicast vs. Unicast
Bandwidth Usage for Clients Listening to an 8 Kbps Audio Stream
Multicasting at Transport Layer
• Multicasting uses UDP (User Datagram Protocol) as
its underlying transport protocol.
No retransmission of packets or acknowledgment in the
TL .
Any reliability must be engineered-in at higher level.
• The more reliable Multicasting forms, do have
negative acknowledgments.
Multicasting at Network Layer
(IP Multicasting)
1.
Addressing
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2.
IP addresses Class D
Address the message to Multicast group
Group Management
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Uses Internet Group Management Protocol (IGMP)
3. Routing
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Message goes to Rendez-vous Points (RP)
RPs forward message to devices in domain and other RPs.
The Multicast Routing Protocol used is (PIM-SM)
Shortest Path Tree
Source
Group Member 1
Group Member 2
Rendezvous Point Tree
Source 1
Rendezvous Point
Source 2
Shortest Path Trees
RP Tree
Group Member 1
Group Member 2
Applications that use Multicasting:
• Video conferencing
• Corporate communications
• Distance learning
• Distribution of software
• Stock quotes
• News
Sources and refrences
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http://www.savetz.com/mbone/ch3_1.html
http://en.wikipedia.org/wiki/Multicasting
http://abilene.internet2.edu/services/multicast.html
http://www.multicasttech.com/
http://www.internet2.edu/resources/infosheetmulticast.pdf
http://mcast-wiki.internet2.edu/index.php?n=Main.MulticastCookbook
http://www.tcpipguide.com/free/t_IPMulticasting-2.htm
http://www.cisco.com/warp/public/779/largeent/learn/technologies/multicast.
html.
http://www.cisco.com/warp/public/cc/pd/iosw/prodlit/ipimt_ov.htm
http://www.answers.com/topic/multicast?method=22
http://www.uoregon.edu/~joe/understanding-mpeg1-multicast.pdf
http://www.cisco.com/application/pdf/en/us/guest/products/ps6552/c1161/cdc
cont_0900aecd80310883.pdf
ftp://ftpeng.cisco.com/ipmulticast/networkers00/IntroToIPMulticast.pdf
www.iana.org/assignments/multicast-addresses.
http://www.sprintlink.net/multicast/faq.html#JoiningGroups
Questions