Srikanth, : Any body having idea to find the NIC Capacity / BW (10 / 100 Mbps) ? : Whether the interface may be eth0/eth1/ppp0 or some other. Is there any : related IOCTL avialable, if so just give the linux-2.4.18 file path. For ethernet interfaces (devices), you should be able to determine the negotiated speed with either a device specific diagnostic utility (e.g., tulip-diag), or, with recent kernels and drivers, mii-diag, mii-tool, and the preferred ethtool. You can find the source to ethtool here: http://freshmeat.net/projects/ethtool/?topic_id=146%2C150 If this doesn't provide your answer, you may find a faster (if terser) answer from linux-net....as for determining speed of a serial link from the interface or device--I have no idea! Maybe somebody else on the list? Best of luck, -Martin -- Martin A. Brown --- SecurePipe, Inc. --- mabrown@xxxxxxxxxxxxxx