[DarkFiber]

IP Multicasting

Why Do You Need Multicasting?

“Necessity is the mother of all invention,” a saying derived from Plato’s Republic, holds very true in the world of technology. In the late 1980s, Dr. Steve Deering was working on a project that required him to send a message from one computer to a group of computers across a Layer 3 network. After studying several routing protocols, Dr. Deering concluded that the functionality of the routing protocols could be extended to support “Layer 3 multicasting.” This concept led to more research, and in 1991, Dr. Deering published his doctoral thesis, “Multicast Routing in a Datagram Network,” in which he defined the components required for IP multicasting, their functions, and their relationships with each other.

The most basic definition of IP multicasting is as follows:
Sending a message from a single source to select multiple destinations across a Layer 3 network in one data stream.

If you want to send a message from one source to one destination, you could send a unicast message.
If you want to send a message from one source to all the destinations on a local network, you could send a broadcast message. However, if you want to send a message from one source to selected multiple destinations spread across a routed network in one data stream, the most efficient method is IP multicasting.

Demand for multicast applications is increasing with the advent of such applications as audio and video web content; broadcasting TV programs, radio programs, and concerts over the Internet;
communicating stock quotes to brokers; transmitting a corporate message to employees; and transmitting data from a centralized warehouse to a chain of retail stores.
Success of one-to-many multicast applications has created a demand for the second generation of multicast applications that are referred to as “many-to-many” and “many-to-few,” in which there are many sources of multicast traffic. Examples of these types of applications include playing games on an intranet or the Internet and conducting interactive audio and video meetings.

Check attachment for IP multicast summary explanation & cmds

Attached File(s)

•  IP_Multicast.doc (303K)
  Number of downloads: 1567

This post has been edited by DarkFiber: 29 April 2009 - 06:11 PM

[DarkFiber]

Hello Guys , any questions : )

[Scales]

Hey Dark,

No Questions as i just downloaded the document and haven't read it yet
But just want to say thankyou for this and the other documents you have made. I have got the IPv6 one you wrote as well

Thankyou So much Great help. !

[CiscoCubs]

I'm a big fan, I've been looking for a secondary source to read and this works out great. To tell you the truth, this document reads better then the chapter about "Multicasting" in the Cisco Press Certification Guide. You've got a knack for teaching.

[alcatraz_akpos]

I'm sorry! I was unable to open the file. It seems the file is corrupt. Can I get it from anywhere else?

[muttman]

Thanks again for these docos. Certainly helped me understand M/C more, which helped me pass my BSCI today.

Cheers!

[DarkFiber]

Thanks again for these docos. Certainly helped me understand M/C more, which helped me pass my BSCI today.

Cheers!

Congrats
Glad it helped you

[rhamietron]

Hello Guys , any questions : )

Hi is it possible to have more than one eigrp ip summary address under one interface.

Thanks

This post has been edited by rhamietron: 13 June 2009 - 10:14 PM

[DarkFiber]

Hi is it possible to have more than one eigrp ip summary address under one interface.

Thanks

Kindly post your question in th EIGRP thread, thats the multicast

[vijayraju]

Thank you... Is there any document for implementing IP MULTICAST OVER MPLS DOMAIN...plz send it to vijayaramaraju@ceeyes.com,vijayraju11@yahoo.com...urgent..

Thanks once again.

[badd_guyy]

DarkFiber, on 30 April 2009 - 12:13 AM, said:

Hello Guys , any questions : )

Hi

can you take a look at this post pls. h**p://www.sadikhov.com/forum/index.php?showtopic=172130

i am trying to find an easy way to chk if a network is capable of sending multicast traffic

[DarkFiber]

Any questions guys

[fmX]

Very good manual for IP multicast. Thanks a lot.

[fmX]

But i've got one question about BSR.
What is the difference between BSR and mapping agent (send-rp-discovery) ? I don't understand this part of the PIM. And what means the parameter hash-mask-length of the command ip pim bsr-candidate?

[DarkFiber]

fmX, on 05 December 2009 - 06:55 PM, said:

But i've got one question about BSR.
What is the difference between BSR and mapping agent (send-rp-discovery) ? I don't understand this part of the PIM. And what means the parameter hash-mask-length of the command ip pim bsr-candidate?

(send-rp-discovery) = mapping agent for PIM auto-rp protocol

(ip pim bsr-candidate) = mapping agent for PIM BSR protocol

hash-mask-length for BSR is like a subnet mask so the RP can be responsible for multiple multicast groups
Length of a mask (32 bits maximum) that is to be ANDed with the group address before the hash function is called. All groups with the same seed hash (correspond) to the same RP. For example, if this value is 24, only the first 24 bits of the group addresses matter. This fact allows you to get one RP for multiple groups.

Hope its more clear

[fmX]

So hash-mask-length is used for load balancing between two or more RPs?
And one more: AutoRP is for cisco devices, and BSR is for non-cisco devices. Am i right?

[DarkFiber]

fmX, on 08 December 2009 - 09:58 PM, said:

So hash-mask-length is used for load balancing between two or more RPs?
And one more: AutoRP is for cisco devices, and BSR is for non-cisco devices. Am i right?

kind of, aut-rp is a cisco proprietary , BSR is not.
BSR can work with cisco or any other vendor

[Biggents]

I have had a look at this post, EIGRP and OSPF they are very nice. But where is IS-IS.

If you can provide one that would be great

[DarkFiber]

Biggents, on 09 January 2010 - 05:27 PM, said:

I have had a look at this post, EIGRP and OSPF they are very nice. But where is IS-IS.

If you can provide one that would be great

Thanks. will do so sooon, BGP, ISIS & MPLS in February