[libvirt] problem with outbound limiting

Hi I am using 0.9.4 version of libvirt and want to limit bandwidth. I installed libvirt on ubuntu 11.04 using libvirt source. For this i am using the QOS configuration <devices> <interface type='network'> <source network='default'/> <target dev='vnet0'/> *<bandwidth> <inbound average='1000' peak='5000' burst='1024'/> <outbound average='128' peak='256' burst='256'/> </bandwidth>* </interface> Here the inbound limit is working properly but the outbound is limiting but not with values which is give Here are the scenarios i tested and the results when i gave average as 2048 --- it is limiting with 600 -- 700 kb average result ===================== 2048 (2mpbs) 600-700 kb 4096 (4mbps) 1 MB/s 10240 (10mbps) 2-3 MB/s 12288 (12 mbps) 3-4 MB/s 20480 (20 mbps) 16-18 MB/s Is this the expected behavior or some thing is missing If this is the expected behavior ,then in what ratio it is limiting. Please help me Thanks in advance. -- Thanks and Regards, Upendra.M