UDP Multicasts 1

[EllaMonroe]

Hi, I went to go see a partner of ours and he was talking about his current tech setup. Some things I need to clear up are:
What would UDP multicasts consist of?
Store and forward?
The UDP multicasts are in a private WAN scenario and not on the internet.

I can see that multicast would allow him to shoot updates from one location to multiple locations at the same time but its the UDP part that throws me the curve ball.

thank you

 

[Khoeth]

You definately don't win the Descriptive author of the year award, but I believe the following (taken from

http://www.tack.ch/multicast/

) should clear things up for you. Multicast is UDP based and comparable to Broadcast (all hosts get, and react to, the information). It is the nature of UDP protocol to "not hold itself accountable" for whether information was or was not recieved (unlike TCP). By using multicast on a WAN, I assume your partner wants to send information to certain systems, yet exclude those the information is irrelevent to. This is done by shooting out the information (or connection initialization so that information can be sent) to an IP address range that all of the systems that need the information can be found on. Not all of the systems on this IP range are configured to accept this information, and here we see why UDP is the preferred protocol. If we used TCP, every host that declined the information/connection would send information back to the source of the multicast refusing the source's attempt (something along the lines of an ACK|RST packet), but by using UDP, we eliminate all of this unnecessary network traffic over the WAN/LAN. Because UDP simply doesn't care, the source isn't flooded with responses from systems that the multicast is not sent out for. I hope I have been of some help.

Khoeth Mora
patton525@hotmail.com

feel free to Contact me at patton525@hotmail.com