TBF or Token Bucket Filter is a tool from the linux kernel. It can be inserted as a “queueing discipline” for an Ethernet device. TBF is usually employed to limit the bandwidth.
I tried to configure TBF on my Ubuntu 9.10 VMware box, but I got disappointing results: I only got around 100kbps, no matter what I configured. I tried the same setup on a physical server, with the same results.
After a full afternoon of experimenting and Googling, I was able to solve the issue by disabling offloading:
# ethtool -k eth0 Offload parameters for eth0: Cannot get device flags: Operation not supported rx-checksumming: on tx-checksumming: on scatter-gather: on tcp-segmentation-offload: on udp-fragmentation-offload: off generic-segmentation-offload: on generic-receive-offload: off large-receive-offload: off # ethtool -K eth0 sg off # ethtool -K eth0 tso off # ethtool -K eth0 gso off # ethtool -k eth0 Offload parameters for eth0: Cannot get device flags: Operation not supported rx-checksumming: on tx-checksumming: on scatter-gather: off tcp-segmentation-offload: off udp-fragmentation-offload: off generic-segmentation-offload: off generic-receive-offload: off large-receive-offload: off
