search for: netem

Hi, I am using netem to add loss and then adding another qdisc within netem according to the wiki. Then i want to change the netem drop probability without having to delete the qdisc and recreate it. I try it but I get invalid argument: thorium-ini hedpe # tc qdisc add dev ath0 root handle 1:0 netem drop 1% thori...

I''m trying to setup a netem delay with no luck (using iproute2-2.6.8, compilation broke during arpd compile, so I use the tc binary in the tc/ subdir, there''s also a q_netem.so there). kernel is 2.6.8.1, compile with CPU cycle counter as time reference. I was using sch_delay of 2.6.7 happily with something like: tc q...

Thanks in advance! Summary: when I load netem and teql together, teql doesn''t work correctly. (If I load teql only, everything is fine) I loaded both netem and teql. Netem is associated with eth0, and teql is associated with both eth0 and eth1. But traffic only goes out of eth1. Attached are the commands that I used to configure teq...

...w, then a prio 3 filter that will match everything that the prio 1 and 2 filters didn''t get? Thirdly, I haven''t seen this actually written down anywhere, so I''d like to double check: the fw filter matches any packet with non-zero fwmark value, yes? Finally, when using netem `tc qdisc ls` always shows a duplicate value of around %75, even when I don''t set it, and setting the duplicate value seems to have no effect. Is this a header mismatch between the kernel and userland? Apologies to those who don''t like multiple questions in one email :-) A...

I''m trying to use tc and netem to delay packets from several different machines as they exit via eth0. Assume two source IPs, 10.0.0.122 and 10.0.0.133. I''d like to delay packets from the first one by 200ms, and packets from the second one by 300 ms. Any other traffic should be sent out normally. Here''s what I...

Hi! We want to run TCP streams to several port numbers through one interface, each with a different delay set by Netem. E.g. TCP streams to port 80 could have 50ms delay, while TCP streams to port 81 could have 100 ms delay and so on. We have tried to solve this by using a combination of tc filter and netem rules, but we can''t get it quite right. We are considering one class per port, each with their own...

Hi all, I''m running some tests with netem and I noticed some strange behaviour that looks like a bug: I''m pinging another machine and adding delay with netem. When I tell netem to give me a 10ms delay, it works fine. The problem is that when I ask for a 11ms delay, it gives me 20ms! It happens for any value between 11ms an 20m...

Hi, I am using iproute2 to setup fowarding, adding routes like "ip route add 192.168.1.3 via 192.168.1.2" I was wondering where in the kernel I can insert probabilistic packet loss only for forwarded packets? So that for instance I can drop 5% of all forwarded packets? I don''t need help with the actual code, just need help finding where to insert this code :) Thanks! George

hi i tried the example given on the examples page to duplicate selected traffic like tc qdisc add dev eth0 root handle 1: prio tc qdisc add dev eth0 parent 1:3 handle 3: netem duplicate 40% tc filter add dev eth0 protocol ip parent 1:0 prio 3 u32 match ip dst 11.0.2.2 flowid 1:3 when i ping from 11.0.2.2 to this interface my machine hangs. the same thing works for drop or delay. i would appreciate if someone can tell me what i am doing wrong. thanks. ________...

Hi all, I am currently trying to emulate a satellite link, via Netem, on a testbed which is OSPF-enabled. I''d like to set up a Netem box between two routers. Since all routing between routers is dynamic, I''m wondering how to set up OSPF on my Netem box? Could someone indicate me if it is feasible and give me some guidelines to possibly do so? T...

Hi, I''m trying to set up 15 different delay intervals for packets leaving on an interface, using netems hanging off of a 16-band prio. I''m having trouble adding anything to bands higher than 10. Here''s what I tried: tc qdisc add dev eth0 root handle 1: prio bands 16 \ priomap 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I want all default traffic to go to the highest...

...h, and use TEQL at end nodes to send packets to both paths. Questions: How to configure TEQL when there is a gateway (I only found examples with two direct connections)? Furthermore, can NIST Net be bound to only eth1 of an end computer so that I don''t even need a gateway machine? 2. Use NetEm. I just learned about it from the mailing list today. It seems that NetEm can be bound to one interface (eth1 in this case), so I don''t need a third computer to control the path properties. Is it true? Which method is better? Is there any method? Thanks a lot, -Ji

...re packets from different "remote" locations get delayed by different amounts of time, depending on which remote location we''re pretending they are from. Currently, I''m doing this using the ''prio'' qdisc to obtain multiple bands, and hanging a different netem qdisc off each of the branches to delay packets, like this (assuming two remote locations): # create three bands, and place all default traffic in the first one: tc qdisc add dev eth0 root handle 1: \ prio bands 3 priomap 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 # the second and third bands of the p...

...want to add a delay of 50ms to each outgoing packet from an interface. This is to simulate a large pool of multiple modem users so I also need to add b/w limits etc (which seems to be easy to do). From the mailing list I could fine 2 qdiscs that can simulate latency : "delay" & "netem". Neither of them is working on my setup though ( Fedora core2 [2.6.5] or RHEL 3.0 update 2 or gentoo [2.6.8] ). Is something special needed to enable these qdiscs ? I tried applying the patch (http://www.uwsg.iu.edu/hypermail/linux/net/0403.2/0019.h tml) and recompiled the kernel but the tc...

There is an design problem with the qdisc interface that causes qlen related bugs in netem, tbf, and other qdisc''s that peek at the top of the queue. The problem is that requeue needs to be called from the dequeue function but requeue can fail. If requeue fails, then the calling qdisc can not properly handle the error. If it returns NULL, then the parent''s expectation...

...k. The latter takes from a multi-megabyte "fair usage" bucket that refills at 50 kbit/s. I don''t have good packet loss numbers, so I''m going to start with 1% and see how sensitive performance is.) Can anyone tell me how to do that? My problem is that trying to set up netem incoming is proving to be a pain: # tc qdisc add dev spare handle ffff: ingress # tc qdisc add dev spare parent ffff: handle 10: netem delay 300ms 50ms 25% loss 1% RTNETLINK answers: Unknown error 4294967295 I''m not at all certain why this doesn''t work. I''m told that t...

Hello everybody, I''m trying to set up netem on a SuSE box (kernel 2.6.16), but I''m having some weird problems, considering that on my Gentoo laptop (kernel 2.6.17) it worked fine. If I write: # tc qdisc add dev eth0 root netem delay 20ms loss 20% and then try pinging another machine over eth0, I get a 24ms delay but no packet los...

...ke McConnell) > 6. Re: Sip Traffic (Marius Corici) > 7. Re: HTB - Rate errors (Luciano Ruete) > 8. trying to get time control working (William Bohannan) > 9. trying to get time working - had error in first email > (William Bohannan) > 10. how to change classful netem loss probability? (George Nychis) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 26 Apr 2006 16:26:27 +0200 > From: sophana <sophana@zizi.ath.cx> > Subject: Re: [LARTC] Sip Traffic > To: lartc@mailman.ds9a.nl...

...y, as well as head-of-line blocking of other flows that do not use zerocopy. Instead of stalling, revert to copy-based transmission. Tested by sending two udp flows from guest to host, one with payload of VHOST_GOODCOPY_LEN, the other too small for zerocopy (1B). The large flow is redirected to a netem instance with 1MBps rate limit and deep 1000 entry queue. modprobe ifb ip link set dev ifb0 up tc qdisc add dev ifb0 root netem limit 1000 rate 1MBit tc qdisc add dev tap0 ingress tc filter add dev tap0 parent ffff: protocol ip \ u32 match ip dport 8000 0xffff \ action mirre...

...y, as well as head-of-line blocking of other flows that do not use zerocopy. Instead of stalling, revert to copy-based transmission. Tested by sending two udp flows from guest to host, one with payload of VHOST_GOODCOPY_LEN, the other too small for zerocopy (1B). The large flow is redirected to a netem instance with 1MBps rate limit and deep 1000 entry queue. modprobe ifb ip link set dev ifb0 up tc qdisc add dev ifb0 root netem limit 1000 rate 1MBit tc qdisc add dev tap0 ingress tc filter add dev tap0 parent ffff: protocol ip \ u32 match ip dport 8000 0xffff \ action mirre...