Help me with ETHERNET TCP Connections

[tjalps]

ETHERNET TCP Connections

Hello!

I have plan to transfer some packets of data form my PIC-uc aplication over Xport unit thrue ETHERNET to PC based TCP server. Each unit will transfer small data packets ( 100 bytes ) every 60 seconds. I'd like to now if is better to keep conection live betwen this transmisions or should I establish connection for each transfer separetly.

I'm also interested on wath should I be careful with transfer protocols?

Since I heard that big packets can be broken on parts I'll put header for start, with datalength byte and also checksum byte to make this protocol sucessful. Is this OK?

Can anyone give me some advices about good and sucesful ETHERNET transfers of data. Any advice is wellcome!

Best regards!

 

[PaulHolland]

Re: ETHERNET TCP Connections

Hi,

Its better to keep the TCP connection alive, its also much faster since a new connection made cost time and since it does not cost any thing to keep it open ist much better.

TCP can be seen as a error free data pipe, if you put packets of data in to it you will get them out on the other side of the link error free... your packets can be broken into smaller chunks and your software should be able to take care of this, you can since all chunks always will arrive in the correct order.

If your application can suffer from data loss you can also use UDP, advantage is that you don't need to make or brake a link but arrival and order are not always 100% what you expect .. if your application is only over a small network (Ethernet) than you can expect 100% of the UDP to be delivered correctly.

If you are pushing that TCP over ethernet the MTU (Max Transmission Unit) before they are broken into chunks by TCP is about 1500 bytes..
You can also find out the MTU of your network before you start transmitting packets to be 100% sure they are not broken, but better is to write your code so it can handle these events..

good luck,

Paul.

 

[makri]

Re: ETHERNET TCP Connections

I think you are taking about UDP, check for UDP details You will get answer to your question

 

[tjalps]

Re: ETHERNET TCP Connections

Hello!

No I have no intention to use UDP. I'm primarly interested in TCP.

Regards!

 

[mr_ghz]

Re: ETHERNET TCP Connections

Hi tjalps

Take care with a long-time open TCP connection which is not transfering data. Some firewalls could break your connection.
If your connection never runs through a firewall, it's OK to leave the connection open. If you want to communicate over internet I would rather close and reopen the connection.

Bye

 

[tjalps]

Re: ETHERNET TCP Connections

I'm inside LAN and I have no intention to go through to WAN.

Regards!

 

[ciombe]

Re: ETHERNET TCP Connections

Tell me please how can you transfer information from pic to xport ?
I'm new in xport and I know hou can I do that !
I powered the xport and it work nice in lan,I can setting I can view web pages loaded in but I don't how can I contunue the project.
Please help me if it's posible.

Thank you very much

Don Mario
marimar@pcnet.ro

 

[tjalps]

Re: ETHERNET TCP Connections

Hello!
Only short info!

You can comunicate with PIC to Xport over RS232. Read more info in added manuals.

Regards!

 

[Antharax]

Re: ETHERNET TCP Connections

What's the cost of setting up a TCP-connection?

3-5 packets (use a sniffer and find out for yourself)

I think it's best when you setup a new connection every time you want to send something. Then you have no problem when the connection drops for a reason and you could use more devices on the same server (when you wanted to do that)

Antharax

 

[ciombe]

XPort problem !

HI,

Can you tell me,how can I acces serial port from XPort directly without
java applet.

Thanks

Don Mario

 

[mexxyoyo]

Re: ETHERNET TCP Connections

R u talking about Isolation Transformer?....
about chip of internet interface with RJ45?~
If yes~~I have some website that support some informations for u