Difference between revisions of "IP Multicast"

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== Principle ==
+
== Multicast Applications ==
 +
=== One-to-Many ===
 +
where one sender sends data to many receivers.
 +
*This type of application may be used for audio or video distribution, push media, announcements, monitoring, and so on.
 +
*If a one-to-many application needs feedback from receivers, it becomes a many-to-many application
 +
=== Many-to-Many ====
 +
where a host can be a sender and a receiver simultaneously or where two or more receivers also act as senders.
 +
*Receiving data from several sources increases the complexity of applications and creates different management challenges.
 +
*Using a many-to-many multicast concept as a foundation, a whole new range of applications may be built (for example, collaboration, concurrent processing, and distributed interactive simulations).
 +
=== Many-to-One ===
 +
where many receivers are sending data back to one sender.
 +
*Used by financial applications and networks. Other uses include resource discovery, data collection, auctions, and polling.
 +
== IP multicast Addresses ==
 +
=== Locally scoped (reserved link local) addresses === 
 +
*Reserved by the Internet Assigned Numbers Authority (IANA) for network protocol use.
 +
*Address range is from 224.0.0.0 through 224.0.0.255.
 +
*Multicasts in this range are never forwarded off the local network, regardless of Time to Live (TTL). Usually, the TTL is set to 1.<br/>
 +
{|border=1
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|+ Some local Scope Multicast addresses
 +
|- bgcolor=lightgrey
 +
! Address !!  Meaning
 +
|-
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|224.0.0.1 || All multicast Systems on a subnet
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|-
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|224.0.0.2 || All multicast Routers on a subnet
 +
|-
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|224.0.0.4 || All Distant vector  multicast routing protocol routers
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|-
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|224.0.0.5 || All OSPF Routers
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|-
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|224.0.0.6 || All OSPF designated Routers
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|-
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|224.0.0.9 || All RIPv2 Routers
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|-
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|224.0.0.10 || All EIGRP Routers
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|-
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|224.0.0.13 || All PIMv2 Routers
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|-
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|}
  
 +
=== Globally scoped addresses ===
 +
*Allocated dynamically throughout the Internet.
 +
*Address range is from 224.0.1.0 through 238.255.255.255.
 +
*The 224.2.X.X range is used in Multicast Backbone (Mbone) applications. Established by the Internet Engineering Task Force (IETF) to multicast audio and video meetings, Mbone is a collection of Internet routers that support IP multicasting on which various public and private audio and video programs are sent.
 +
=== Limited (administratively) scoped addresses ===
 +
*Reserved for use inside private domains. Similar to the private IP address space that is used within the boundaries of a single organization, limited or administratively scoped addresses are constrained to a local group or organization.
 +
*Address range is from 239.0.0.0 through 239.255.255.255.
 +
*Organizations can use limited scope addresses to have local multicast applications that will not be forwarded over the Internet.
 +
*Within an autonomous system or domain, the limited scope address range can be further subdivided so that local multicast boundaries can be defined. This subdivision is called address scoping and allows for address reuse between smaller domains. The administratively scoped multicast address space is divided into the following scopes:
 +
 +
*Organization-local scope (239.192.0.0 to 239.251.255.255)
 +
*Site-local scope (239.255.0.0/16, with 239.252.0.0/16, 239.253.0.0/16, and 239.254.0.0/16 also reserved)
 
[[Category:Network]]
 
[[Category:Network]]

Revision as of 22:43, 26 February 2009

Multicast Applications

One-to-Many

where one sender sends data to many receivers.

  • This type of application may be used for audio or video distribution, push media, announcements, monitoring, and so on.
  • If a one-to-many application needs feedback from receivers, it becomes a many-to-many application

Many-to-Many =

where a host can be a sender and a receiver simultaneously or where two or more receivers also act as senders.

  • Receiving data from several sources increases the complexity of applications and creates different management challenges.
  • Using a many-to-many multicast concept as a foundation, a whole new range of applications may be built (for example, collaboration, concurrent processing, and distributed interactive simulations).

Many-to-One

where many receivers are sending data back to one sender.

  • Used by financial applications and networks. Other uses include resource discovery, data collection, auctions, and polling.

IP multicast Addresses

Locally scoped (reserved link local) addresses

  • Reserved by the Internet Assigned Numbers Authority (IANA) for network protocol use.
  • Address range is from 224.0.0.0 through 224.0.0.255.
  • Multicasts in this range are never forwarded off the local network, regardless of Time to Live (TTL). Usually, the TTL is set to 1.
Some local Scope Multicast addresses
Address Meaning
224.0.0.1 All multicast Systems on a subnet
224.0.0.2 All multicast Routers on a subnet
224.0.0.4 All Distant vector multicast routing protocol routers
224.0.0.5 All OSPF Routers
224.0.0.6 All OSPF designated Routers
224.0.0.9 All RIPv2 Routers
224.0.0.10 All EIGRP Routers
224.0.0.13 All PIMv2 Routers

Globally scoped addresses

  • Allocated dynamically throughout the Internet.
  • Address range is from 224.0.1.0 through 238.255.255.255.
  • The 224.2.X.X range is used in Multicast Backbone (Mbone) applications. Established by the Internet Engineering Task Force (IETF) to multicast audio and video meetings, Mbone is a collection of Internet routers that support IP multicasting on which various public and private audio and video programs are sent.

Limited (administratively) scoped addresses

  • Reserved for use inside private domains. Similar to the private IP address space that is used within the boundaries of a single organization, limited or administratively scoped addresses are constrained to a local group or organization.
  • Address range is from 239.0.0.0 through 239.255.255.255.
  • Organizations can use limited scope addresses to have local multicast applications that will not be forwarded over the Internet.
  • Within an autonomous system or domain, the limited scope address range can be further subdivided so that local multicast boundaries can be defined. This subdivision is called address scoping and allows for address reuse between smaller domains. The administratively scoped multicast address space is divided into the following scopes:
  • Organization-local scope (239.192.0.0 to 239.251.255.255)
  • Site-local scope (239.255.0.0/16, with 239.252.0.0/16, 239.253.0.0/16, and 239.254.0.0/16 also reserved)