CBQ is not limiting bandwidth!!!

Deepika Kakrania (deepika@sasken.com)
Thu, 26 Jul 2001 18:27:02 +0530 (IST)


Hi all,

I am using CBQ to limit the packet transmission rate to some small
value(say 1Mbit...10Kbit) over an ethernet interface so that I can see
queue building up at output side (having the queue length >10 or so while
sending heavy traffic).

The set up I am using is something like this

dst router src
---------- ---------- ----------
| | eth1 | | | |
| |-------------------- | |-------------------| |
--------- --------- ---------
178.18.0.1 178.18.0.2 178.19.0.1 178.19.0.2

All 3 m/cs are connected thru' cross cables. The src m/c sends the
traffic to dst m/c using netperf.
I am defining only one class at m/c router on interface eth1. The tc
rules set up for doing so are following.

tc qdisc add dev eth1 root handle 1: cbq bandwidth 10Mbit cell 8 avpkt
1000 mpu 64

tc class add dev eth1 parent 1:0 classud 1:1 cbq bandwidth 10Mbit rate
1kbit allot 1514 cell 8 weigth 100bit prio 5 maxburst 20 avpkt 1000

tc filter add dev eth1 parent 1:0 protocol ip prio 100 u32 match ip dst
178.18.0.1 flowid 1:1

But the result I get from netperf gives me the throughput of 6.81 Mbit
even after setting the rate to 1Kbit.

Another problem is that the queue length is 1 after enqueueing
the packet at any time even if I send the traffic using 'ping -f
178.18.0.1'.

Can anyone tell me what could be the problem? Am I missing something?

Thanks in advance.

regards,
Deepika

Ps: I am not subscribed to this mailing list so please reply to my
personal account.

----------------------------------------------------------------------------
Deepika Kakrania
Sasken Communication Technologies Limited

Phone No:(080) 5578 300 Extn:8059
5289906 (res)
Email: deepika@sasi.com

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