Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

multicasting

Posted on 2010-08-28
8
765 Views
Last Modified: 2012-05-10
Hi,

Say if I want to multicast some data to a group of IPs, what will be the destination address in my IP field for such packets ?

For unicast, the destination address will be the IP of the destination and for broadcast, it will be the network address, it will be 255.255.255.255...how about  in the case of multicast packet ?

How multicast works ???
0
Comment
Question by:its_ns_04
8 Comments
 
LVL 3

Expert Comment

by:michko-au
ID: 33551565
Multicasting is much like broadcasting, however the router only distributes packets to the segments with machines 'subscribed' to the multicast group. The address will be something like 224.0.0.1

This link should help: http://tldp.org/HOWTO/Multicast-HOWTO.html
0
 
LVL 1

Author Comment

by:its_ns_04
ID: 33725622
The how to link which you have mentioned doesn't say what to what addresses the machine will send packets to..

It simply says on configuring multicasting....

I am looking for something like, if i need to send some message to a group of address such as 192.168.1.3, 192.168.1.8,192.168.1.30.192.168.4.5, how does it send ???
0
 
LVL 57

Accepted Solution

by:
giltjr earned 250 total points
ID: 33744904
You/your program decides what the IP address is.

Typically the client program will talk to the server program using a unicast address, the server will then tell the clients what multicast IP address and port to listen on.

The multicast IP subnet/range is 224.0.0.0/4 (from 224.0.0.0 to 239.255.255.255)
0
Efficient way to get backups off site to Azure

This user guide provides instructions on how to deploy and configure both a StoneFly Scale Out NAS Enterprise Cloud Drive virtual machine and Veeam Cloud Connect in the Microsoft Azure Cloud.

 
LVL 32

Expert Comment

by:harbor235
ID: 33744954
Initially communication begins via unicast to the source, once the receiver and the devices in between join the appropriate group and build the multicast trees, the traffic is then directed to the source group IP.  The group IP can be any address out of the reservered Mulicast IP,  here is a link for best pratices assigning multicast addresses and thier approriate ranges.

http://tools.ietf.org/html/rfc3171

harbor235 ;}  
0
 
LVL 17

Expert Comment

by:kadadi_v
ID: 33745001
More Info:

http://en.wikipedia.org/wiki/IP_multicast

Regards,
vijay
0
 
LVL 16

Expert Comment

by:SteveJ
ID: 33745429
it_ns_04,

Do you understand what the experts are telling you? Multicast addresses are assigned if you want them to be global. EIGRP uses a multicast address, for example, and it's published. If you write an application that uses multicast, you could apply for an address that your application would "own".

Here are some you may recognize:

224.0.0.0       Base address (reserved)
224.0.0.1       The All Hosts multicast group addresses all hosts on the same network segment.
224.0.0.2       The All Routers multicast group addresses all routers on the same network segment.
224.0.0.5       The Open Shortest Path First (OSPF) AllSPFRouters address is used to send Hello packets to all OSPF routers on a network segment.
224.0.0.6       The OSPF AllDRouters address is used to send OSPF routing information to designated routers on a network segment.
224.0.0.9       The Routing Information Protocol (RIP) version 2 group address is used to send routing information to all RIP2-aware routers on a network segment.
224.0.0.10       The Enhanced Interior Gateway Routing Protocol (EIGRP) group address is used to send routing information to all EIGRP routers on a network segment.
224.0.0.13       Protocol Independent Multicast (PIM) Version 2
224.0.0.18       Virtual Router Redundancy Protocol (VRRP)
224.0.0.19 - 21       IS-IS over IP
224.0.0.22       Internet Group Management Protocol (IGMP) Version 3
224.0.0.102       Hot Standby Router Protocol Version 2
224.0.0.251       Multicast DNS (mDNS) address
224.0.0.252       Link-local Multicast Name Resolution (LLMNR) address
224.0.1.41       H.323 Gatekeeper discovery address

Good luck
Steve
0

Featured Post

Netscaler Common Configuration How To guides

If you use NetScaler you will want to see these guides. The NetScaler How To Guides show administrators how to get NetScaler up and configured by providing instructions for common scenarios and some not so common ones.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Short answer to this question: there is no effective WiFi manager in iOS devices as seen in Windows WiFi or Macbook OSx WiFi management, but this article will try and provide some amicable solutions to better suite your needs.
When it comes to security, there are always trade-offs between security and convenience/ease of administration. This article examines some of the main pros and cons of using key authentication vs password authentication for hosting an SFTP server.
Viewers will learn how to connect to a wireless network using the network security key. They will also learn how to access the IP address and DNS server for connections that must be done manually. After setting up a router, find the network security…
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…

809 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question