added some use cases

This commit is contained in:
Steffen Vogel 2015-07-20 16:06:59 +02:00
parent fda10984ed
commit dd8e4fd7ec

View file

@ -4,15 +4,31 @@ This tool uses the 3-way TCP handshake to measure the real RTT of a TCP connecti
### Usage
###### Use case 1: collect probing measurements
Run TCP SYN/ACK probes to measure round-trip-time (RTT):
./netem probe 8.8.8.8 > probing.dat
###### Use case 2: convert measurements into delay distribution table
Collect measurements to build a tc-netem(8) delay distribution table
###### Use case 3
The output of this command and be stored in a file or directly passed to the `emulate` subcommand:
./netem probe 8.8.8.8 | ./netem emulate
./netem emulate < probing.dat
To apply the network emulation only to a limit stream of packets, you can use the `mark` tool:
sudo LD_PRELOAD=${PWD}/mark.so MARK=0xCD ping google.de
Please make sure the specify the environmental variables after the sudo command!
This is necessary, as `ping` is a SUID program.
The dynamic linker strips certain enviromental variables (as `LD_PRELOAD`) for security reasons!
### Building
##### Install libnl
@ -46,6 +62,7 @@ For building libnl (make libnl)
- http://www.infradead.org/~tgr/libnl/
- https://www.kernel.org/doc/Documentation/networking/timestamping.txt
- https://github.com/shemminger/iproute2/tree/master/netem
- [tc-netem(8)](http://man7.org/linux/man-pages/man8/tc-netem.8.html)
### Author