Hi, When dealing with IP, is UDP the only one allowed to broadcast Packets or is TCP also allowed? I read that it was only UDP but that was from a questionable source. Thanks

Most of the internet doesn''t even support multicast over UDP!

This is required under IPv6, but not the IPv4 most routers and OSes still use.

snowball, broadcast does not work with TCP. You need to use UDP.

What the AP was getting at is that broadcast typically only works on your local LAN. You can''t broadcast to the Internet in general.

-Mike

Thanks for the replies.


Just wanted to make sure!

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Original post by Anonymous Poster
Most of the internet doesn''t even support multicast over UDP!

This is required under IPv6, but not the IPv4 most routers and OSes still use.

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Multicast != Broadcast

Yes, it is *very* important to note that Multicast is not the same as Broadcasting. While every network device I can think of supports the handling of broadcasting, multicast is hit and miss. Multicasting is a great idea (in theory..which is a nice place to be) but the implementation has left much to be desired...

~S''Greth

The fact that TCP doesn''t work over broadcast or multicast can be concluded from common sense.

TCP requires ACK packets. If an ACK isn''t received, the TCP (implementation) resends packets. In broadcasting, you cannot know how many receivers there are, thus you cannot know how many ACKs you should expect.
Apart from that, hosts are free to come and go in broadcasting and multicasting. Thus, building connections is completely impossible anyway.

cu,
Prefect

quote:

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Original post by Prefect
The fact that TCP doesn''t work over broadcast or multicast can be concluded from common sense.

TCP requires ACK packets. If an ACK isn''t received, the TCP (implementation) resends packets. In broadcasting, you cannot know how many receivers there are, thus you cannot know how many ACKs you should expect.
Apart from that, hosts are free to come and go in broadcasting and multicasting. Thus, building connections is completely impossible anyway.

cu,
Prefect

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There are experimental TCP implementations/extensions that /do/ work in broadcast and multicast, though. These extensions are not part of any current standard, though. But they could very well be in the future.