networking

calculating the time taken for downloading a 20 mb file via 3g network

Hi, how to find out the time that will be taken for downloading a 20 mb file via 3g mobile ? In theory what is the mathematics to find that out ? ...

Getting TCP Socket statistics in Windows

Is there a way to get a specific socket statistics in windows? I'm most interested in the number of retransmissions a specific socket had, and doing it without using winpcap or similar solutions. Windows should store such an interesting number somewhere, no? ...

How does a Linux socket buffer overflow?

I have a Java reader application that reads from a multicast socket on a Linux 64-bit platform (2.6.18). The socket size has been set to 2 MB. When the reader cannot read fast enough the socket "overflows", i.e. packets are dropped from the buffer. What I would like to know is how the Linux kernel drops packets out of the socket buffe...

basic networking question on URLS

Lets say there is a website called www.hello.com So what really is www - is it the name of the machine? If that is so, hello.com is the domain, which means there can be only 1 machine in hello.com that is called www? Second and related question is, why is stackoverflow http://stackoverflow.com and not www.stackoverflow.com? Thanks in ...

Odd Behavior when Connecting to my Program

I'm using Twisted to implement a server, of sorts. When I test it, the first line it receives is always strange: Starting Server... New connection from 192.168.1.140 192.168.1.140: ÿûÿû ÿûÿû'ÿýÿûÿý\NAME Blurr 192.168.1.140: \NAME Blurr (for both inputs I sent \NAME Blurr.) This is the code that prints the input: def lineReceived(s...

(How) Can I find the socket type from the socket descriptor?

I am writing a program to capture socket network flow to display network activity. For this, I was wondering if there is any way I can determine the socket type from the socket descriptor. I know that I can find socket family using getsockname but I could not find a way to find socket type. For instance, I want to find if this socket w...

Force the iPhone to simulate doing CPU-intensive tasks?

For a normal app, you'd never want to do this. But ... I'm making an educational app to show people exactly what happens with the different threading models on different iPhone hardware and OS level. OS 4 has radically changed the different models (IME: lots of existing code DOES NOT WORK when run on OS 4). I'm writing an interactive t...

How to make Android Virtual Device access the internet?

The internet is not available when I access it from the Android Virtual Device, any idea how can I configure it to do so? ...

Saving all network i/o of a program

Normally I use tcpflow to debug network i/o, but it doesn't seem to have any way to filter by process - so I need to manually figure out which files come from the program being debugged, and which are completely unrelated traffic. Usually both are mostly http so port filtering is out of the question, and filtering by remote hostname is o...

Server <-> silverlight client communication with potential heavy traffic

I'm working on a design for my new application and I need to make a decision what sort of communication is best for Silverlight client and a server. (it could be a winform app or a web app) Couple of main points: Multiple Silverlight clients will connected to the Server. Most of the client-to-client communication will go through the s...

What does destination mac address field contains, when the source doesn't know address of remote machine

What does destination mac address field contains, when the source doesn't know address of remote machine ? (say opening page from google.com from my machine) And while broadcasting the packet, what does mac-address field contains? ...

tipc protocol in windows

Hi, Any idea for TIPC protocol on Windows systems or any similar protocol which is available on windows ? Thanks Arpit ...

How to host game on ftp using asp.net

Is it possible to host a game say counterstrike on ftp. eg. http://www.gamecp.com/ This provides a game control panel to handle server from website. How game gets started on hosting server. Do we needs to install game on hosting server though commands given in its API. or is it there some other procedure to host game on hosting server ...

java - multiplayer connection

Ok so I'm not Java expert but I'm just programming this java applet game for fun to test my skills. the hardest part so far has been blocked tiles and coming on and off new maps. Anyways, my current game is located at http://mystikrpg.com/jrpg I know, the design is really really simple and bland but I plan on changing that later. They ar...

Is OCaml suitable to write networking servers?

Hello, I was wondering if OCaml will perform well in terms of performance and ease of implementation while dealing with typical client/server interactions over TCP in a multi threaded environment.. I mean something really typical like having a thread per client that receives data, operated changes on game states and send them back to cli...

c# simple server to receive connection from internet

Hi, I have made a simple server running locally using tcplisten and it works fine over local network e.g. (127.0.0.11:8888). But how do I now receive connections to the server from the internet, what ip and port do I set?? Thanks ...

How do I send a RST instead of a normal close, for testing?

I have some code that seems to not handle it well when a TCP connection is closed via the RST flag instead of a normal handshake for closing the connection. The "connection reset by peer" situation. I'd like to write a TCP server that always closes via RST so that I can reproduce the bug and write some unit tests for this. So... How do ...

How to make Rails Nonblocking?

I have a rails application that occasionally needs to do very slow network calls (that might not ever return) based on a web user hitting a route. If the call is slower than normal (or doesn't return), Rails seems to block, not allowing ANYTHING else to happen (I can't open up another browser and hit a different route, I can't use a dif...

building an sk_buff for egress device linux kernel

Long story short, I am trying to build a very bare bones UDP SKB just to get something onto the wire. The scenario is as follows: I have a kernel module loading that (among other things) overrides the memory location of the standard udp_sendmsg function in /net/ipv4/udp.c. From here I would like to construct an skb to the point where ...

Resources and tools for TCP tuning

I'm developing an application where, to satisfy the performance requirements, tuning of low-level network stuff (such as TCP window size etc) seems to be required. I found the magnitude of my knowledge to be a bit better than "there's TCP and there's UDP", which is far from enough for this task. What resources might I study to get a be...