Testing Multicast on a Private LANs?

SD asks: "I am planning to write and experiment with multicast RTP streaming. I am not sure if my ISP supports multicast at the router level, so I am wondering if there any way I can set up a LAN in my home to experiment with multicast technology." For those of you who don't know what a Multicast network is, you may want to check the HOWTO. It strikes me that building a network to test multicasting would not be something you would want to do in too small of a scale. Without more details about what kind of application is getting tested, what do you feel would be a ballpark numbers (routers, machines, etc) for a network designed for testing multicast applications, and how much would such a thing cost?

Comments

More info about Multicasting

[terpia]

I hate to be a link whore, but i didnt understand very clearly what multicast basically is. These helped me a bit.

AskJeeves Here

MentorTech (PDF)

Bob Stein (boatload of good links at the bottom)

Not much needed to test multicast

[Guy Smiley]

If your ethernet driver supports multicast under Linux (see Documentation/networking/multicast.txt
for an incomplete list of supported hardware, or
look for MULTICAST in the output of "ifconfig")
then all you need is a simple ethernet HUB to connect the test systems. If you have an ethernet
SWITCH, it may or may not support multicast.

After that, it is "simply" a matter of writing code which does multicast. Note that if you have
multiple interfaces on a host, you will need to
specify a route for the multicast communication.

Re:Not much needed to test multicast

[Anonymous Coward]

As far as the Cisco IOS goes, you'll have to check on that yourself, some versions may be quirky. You'll also need to decide on what multicast protocols you plan on using: PIM sparse or dense mode or DVMRP, etc. As far as multicasting across the Internet, you'll need to make sure your ISP supports it. Some do, some don't, others require a special setup such as a GRE tunnel for multicast traffic. Your ISP may support it but it may not be supported my other ISP's, so the reach of multicast may be limited.

As far as your LAN is concerned, all you need to do is make sure the you are running a multicast protocol and have your clients configured properly.

Good luck,

Re:Not that simple

[CharlieG]

Wait till you run into some of the classic multi path problems, Cisco bugs etc

The app I work on at work uses multicast - a LOT. The big problem is router issues. Some version of IOS work with multicast, some don't

Sigh

Multicast programming

[mmontour]

If you go here, you can get source code for a simple multicast client and server program. Run a sender on one PC, a receiver on another, then add as many intermediate routers and boxes as you want.

I am presently working for a company that sells real-time stock market information, and the incoming data feeds from NASDAQ and SIAC (=NYSE) are in multicast format delivered over a private network. So I have a bit of experience with it, although our application doesn't need anything fancy like dynamic routing or supporting a large number of listening clients. I'm using SuSE Linux for some of the application servers, but I've found that OpenBSD is a better solution for routing the data, tunelling it over a secure VPN, etc.

p.s. If you want to know if your ISP supports multicast, just run tcpdump on your gateway and look for multicast or IGMP traffic.

An application for multicasting MP3 audio...

[Ross Finlayson]

One good application for playing with multicast over a LAN is liveCaster. This lets you stream MP3 files via multicast. (Receiving software is also available.)

Also, source code libraries for multicast streaming (using RTP) are available here ("LIVE.COM Streaming Media")