hi,
I am really a newbie in linux traffic control.But i have task to implement a tool similar to
I am really a newbie in linux traffic control.But i have task to implement a tool similar to
the nistnet tool used for netwok emulation tests but which emulates a wireless environment.
I was exploring the use of the traffic control subsystem for this task.In this regard i have
a few questions i need to post in order to clarify my thoughts on how to do this.I am using
tcng to classify traffic and generate the commands necessary to set up the traffic control
structures.
1. A simple task to add say a delay of 10ms to packets goin to a particular destination.I
tried this using a simple fifo queue and a tbf queue but was not able to obtain the required
results.The queue parameters dont have an explicit delay/latency parameter so basically i
want to know how to add a delay/latency to packets goin out thro a particular interface.
A simple script that i tried
dev INTERFACE{
egress{
class(<$latency>) if ip_dst == 10.0.0.14;
class(<$other>) if 1;
prio{
$latency=class {
//how to set these parameters here to achieve the required delay
tbf(limit 10kB, rate 20kbps, burst 2 kB, mtu 1500B);
}
dev INTERFACE{
egress{
class(<$latency>) if ip_dst == 10.0.0.14;
class(<$other>) if 1;
prio{
$latency=class {
//how to set these parameters here to achieve the required delay
tbf(limit 10kB, rate 20kbps, burst 2 kB, mtu 1500B);
}
$other=class {
fifo(limit 10kB);
}
}
}
}
fifo(limit 10kB);
}
}
}
}
2.The second part is similar to the first but involves dropping a percentage of packets
instead of adding a delay to them.Example i need a 10% packet drop for packets coming from
source 1 and heading to dest 2. Example i use a simple fifo queue with a limit of 2 kB in
order to just test random drop capability.When i use the ping utility with a packet size
greater than 2kB i get the message that 0 packets sent and 0 packets received and when the
packet sizes are < 2048 bytes then there is no drop or delay at all.Ne ideas on this one.
3.To implement bandwidth sharing among different hosts.Example 4 hosts are communicating to each other and all traffic between them is routed through a router which is like the
bottleneck and acts as the wireless network environment with the bottleneck capacity as the
known wireless link capacity.I was thinking and am currently trying this using the HTB
queuing discipline.I wanted to know if this idea can be effectively implemented using the
HTB queuing discipline.
Also im having some problems with installation and working of tcng on my Suse 9.2 system
which is running with a 2.6.8 kernel version.Ok the simulator could not be compiled. But
when i tried using the commands generated by the tcng compiler i get the error that dsmark
queuing discipline is not supported.However when i use the root keyword using the tc tool there seems to be no problem.I read that root and dsmark are the same ...or am i wrong about this. Also my kernel has all the parameters enabled for QoS support.I tried compiling iproute2 from source but im not able to since im getting errors while compiling.Can neone throw some light on this.Or is it that there are some compatibility problems with the newer 2.6 kernels.
Im sorry for the long content of the mail.But im a newbie and want to get my thoughts rite
on this and whether its possible.Thanx a million in advance.
regards
vinay
vinay
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