CODEWITHSUNDEEP
socketshttptcpdata-transferlarge-data
swaraj
swaraj

Reputation: 29

how can I transfer large data over tcp socket

how can I transfer large data without splitting. Am using tcp socket. Its for a game. I cant use udp and there might be 1200 values in an array. Am sending array in json format. But the server receiving it like splitted.

Also is there any option to send http request like tcp? I need the response in order. Also it should be faster.

Thanks,

Upvotes: 1

Views: 9038

Answers (4)

John
John

Reputation: 13720

Consider the idea that the issue may be else where or that you may be sending too much unnecessary data. In example with PHP there is the isset() function. If you're creating an internet based turn based game you don't (need to send all 1,200 variables back and forth every single time. Just send what changed and when the other player receives that data only change the variables are are set.

Upvotes: 1

Jeremy Friesner
Jeremy Friesner

Reputation: 73041

how can I transfer large data without splitting.

I'm interpreting the above to be roughly equivalent to "how can I transfer my data across a TCP connection using as few TCP packets as possible". As others have noted, there is no way to guarantee that your data will be placed into a single TCP packet -- but you can do some things to make it more likely. Here are some things I would do:

  1. Keep a single TCP connection open. (HTTP traditionally opens a separate TCP connection for each request, but for low-latency you can't afford to do that. Instead you need to open a single TCP connection, keep it open, and continue sending/receiving data on it for as long as necessary).
  2. Reduce the amount of data you need to send. (i.e. are there things that you are sending that the receiving program already knows? If so, don't send them)
  3. Reduce the number of bytes you need to send. (The easiest way to do this is to zlib-compress your message-data before you send it, and have the receiving program decompress the message after receiving it. This can give you a size-reduction of 50-90%, depending on the content of your data)
  4. Turn off Nagle's algorithm on your TCP socket. That will reduce latency by 200mS and discourage the TCP stack from playing unnecessary games with your data.
  5. Send each data packet with a single send() call (if that means manually copying all of the data items into a separate memory buffer before calling send(), then so be it).

Note that even after you do all of the above, the TCP layer will still sometimes spread your messages across multiple packets, etc -- that's just the way TCP works. And even if your local TCP stack never did that, the receiving computer's TCP stack would still sometimes merge the data from consecutive TCP packets together inside its receive buffer. So the receiving program is always going to "receive it like splitted" sometimes, because TCP is a stream-based protocol and does not maintain message boundaries. (If you want message boundaries, you'll have to do your own framing -- the easiest way is usually to send a fixed-size (e.g. 1, 2, or 4-byte) integer byte-count field before each message, so the receiver knows how many bytes it needs to read in before it has a full message to parse)

Upvotes: 1

user207421
user207421

Reputation: 310850

You can't.

  • HTTP may chunk it
  • TCP will segment it
  • IP will packetize it
  • routers will fragment it ...
  • and TCP will reassemble it all at the other end.

There isn't a problem here to solve.

Upvotes: 4

Artur Opalinski
Artur Opalinski

Reputation: 1092

You do not have much control over splitting packets/datagrams. The network decides about this.

In the case of IP, you have the DF (don't fragment) flag, but I doubt it will be of much help here. If you are communicating over Ethernet, then 1200 element array may not fit into an Ethernet frame (payload size is up to the MTU of 1500 octets).

Why does your application depend on the fact that the whole data must arrive in a single unit, and not in a single connection (comprised potentially of multiple units)?

Upvotes: 1

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