LAN streaming MTU

[soccerdad]

This is not a GBPVR problem or issue but there are lots of good brains here that may have the answer. I have been trying to stream video from a program (dvbdream) to VLC on another computer on my network. I am using UDP on port 1234. It has worked in the past, but now I get a message that says increase the MTU size. It was defaulted at 1500 and I upped it several times. Eventually (around 40000) the message goes away, but the video does not show up. Any ideas? I have no idea what MTU is. I set the receiving PC VLC and the Router to 1500 with no love. I get the same issue if I try to stream to localhost.

[flyswatta]

IIRC, MTU is the maximum transmission unit - the largest size of packet in bytes that can be transmitted. Older routers would only allow smaller sized packets (476 bytes? it's been a while) to be transmitted, which caused seeming performance issues with the default windows MTU of 1500. Essentially, when a packet of 1500 bytes hits a router that can't handle that size, it fragments the packet causing retransmissions, which is the performance issue. Some of the older "network booster" settings adjusted the MTU down to this value to reduce retransmits in this situation.

It sounds like your router is set to 1500, so the max that you'll be able to transmit over your router is 1500. I'm not sure how large you can increase it before it causes other issues. In fact, you're probably causing more problems by having your max packet size > than the router MTU. I'd be really surprised if you had to increase the MTU beyond 1500, but maybe I'm just a little old school about these type of things.

[wtg]

It sounds like a misleading error to me. As flyswatta mentions, 1500 is the default Windows MTU size. Nothing should require anything larger than that. Have you made any other changes to the network maybe? Did you enable jumbo frames or anything? This error is probably just a symptom of some other problem.

[soccerdad]

Thanks for the info. I think it is a network issue, but it might be the output of the streaming program. Is there any software or way to see if it what size packets are being sent, or any other diagnostics that can be run. It has the same problem when it is streaming to localhost. Would that indicate that it is not a router issue?

[wtg]

Yes, that's right. When streaming to localhost the router is out of the picture.

[flyswatta]

If anything is going to show you the actual packet sizes, it'll most likely be ethereal, however, you're probably in deep kimchi if you have to resort to individual packet analysis.

I'm with wtg on this one, it sounds like a misleading error. It's possible that you might have over-tweaked your setup. I know I've never done that

Can you reset your values back to default (dvbdream, VLC, router, and winders) and see what happens?

[soccerdad]

Thanks guys, I now think it is a dream thing or something native to the PC that it does not like. I get the same error to local host so I doubt it is the network devices like the router. I have fresh installs now of dream and vlc, but no love. It worked for a while and then stopped. No biggie. It is just one of those things that I try to figure out just because it is not working. I really don't need it anyway, it is just a game to find the answer. I am just trying to push the sat radio around my LAN. I also have it hardwired to speakers and to a modulator to send to all my TVs, but I like the idea of the sat radio on the lan. I can always use net radio, but this again is just something to learn and tinker with. I installed ethereal and the output frankly scared me:eek:. I have no idea what it is trying to tell me except that it is streaming to the IP address I want it to.

[flyswatta]

I installed ethereal and the output frankly scared me:eek:. I have no idea what it is trying to tell me except that it is streaming to the IP address I want it to.

Now you understand the "deep kimchi" comment I made earlier

Can you somehow record the SAT radio with DVBDream to your disk and then stream it with VLC? I've had good success with VLC streaming multicast, and it was easy to set up.

I gotta get my SAT card hooked up again and start playing with it again...

[soccerdad]

Now you understand the "deep kimchi" comment I made earlier

Can you somehow record the SAT radio with DVBDream to your disk and then stream it with VLC? I've had good success with VLC streaming multicast, and it was easy to set up.

I gotta get my SAT card hooked up again and start playing with it again...

I think I will stay out of the kimchi
I did get it to work with your record and stream the recorded file idea, thanks. I can even do it while the file is open and recording. Now it would be great if I could have it dump the file at the end of my streaming. Otherwise, I will end up with a ton of streamed files. I need to have it fill a buffer file that will self destruct when I quit the program. There is a pause buffer, but I can't get vlc to read it.
Now I know why SUB does not do Radio He said it was a pain, and now I understand more what the issues are. Again, this is just a learning exercise, so back to the books! (or google)