What is the difference derive unicast and multicast? [betwen] [unicast]
Q: What are the differences and what are they used?
-Por
Re:Originally posted by: guy
Thanks spidey. That's fairly close to what I'm learning. I guess what I didn't realize before was that multicast could be applied to the link layer.
multicast IP address (224 – 239) map directly to layer2 multicast addresses.
http://www.cisco.com/univercd/…wk/ito_doc/ipmulti.htm (http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/ipmulti.htm)
Re:Thanks spidey. That's fairly close to what I'm learning. I guess what I didn't realize before was that multicast could be applied to the link layer.
Re:Application – layer 7 (thinks like HTTP, FTP)
Presentation – layer 6
Session – Layer 5
Transport – layer 4 (tcp, udp)
Network – layer 3 (IP)
Datalink – layer 2 (mac addresses)
Physical – layer 1 (the wire)
Lots of time in network we just say "layer 2 or layer 3 or layer 4" it gets right to the point.
Re:Since this has been answered I'm gonna hijack the thread to ask another, somewhat related question. Hope that's ok porbleemo
spidey, could you define the numbered layers you mentioned? I'm in a networking class right now and there has been talk of layers (duh!) but they aren't numbered and they go: physical, link, network (ip), transport (tcp/udp), application. It doesn't look to me like those match up with what you are talking about.
Thanks
Re:Thanks for the timely response!
Re:Unicast is to a single host – more specfically a single layer 2 address. Almost all communication uses unicast. When you talk to a web server you are sending a packet directly addressed to that single host – uni meaning one.
Multicast is a single packet addressed to a group of hosts – multi = many. There are special layer 2 and layer 3 addresses used for multicast. If you see a class D IP address (224.0.0.0 – 239.255.255.255) it is a multicast. The uses are endless – routing protocols use it to send messages to all routers, to keep heartbeats between routers. The biggest application for multicast though is probably video/content distribution. A host will say "hey! I want to see that video that is streaming" and join the multicast group the stream is addressed to. This way the host will receive the video stream.
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Tags: betwen, unicast