« Archives in February, 2008

Packet loss – mismatch switch speed

February 8, 2008 / posted in Uncategorized / No Comments
Link encap:Ethernet  HWaddr 00:16:76:E1:A2:F8
inet addr:xx.xx.xx.51  Bcast:xx.xx.xx.63  Mask:255.255.255.192
inet6 addr: fe80::216:76ff:fee1:a2f8/64 Scope:Link
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:11098 errors:2178 dropped:0 overruns:0 frame:1098
TX packets:1493 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:751041 (733.4 KiB)  TX bytes:171501 (167.4 KiB)
Base address:0x2020 Memory:e0200000-e0220000

If you have packet loss and see RX errors/frame, there could be a problem with the interface settings. In this case, a mismatch speed with the switch (100mbps vs. 10mbps). Solution: correct the speed setting so they match. Command: “ethtool -s eth0 autoneg off duplex full speed 10” (immediate effect but will not remember after reboot) or put into config file for permanency:

## /etc/sysconfig/network-scripts/ifcfg-eth0 
ETHTOOL_OPTS="autoneg off speed 10 duplex full"

Virtual world vs. the real world

February 1, 2008 / posted in Uncategorized / No Comments

A ship drops an anchor and boom, Internet down! Everything is in chaos and the trend is only get worse as we depend more on the Internet for our every day activities. The following diagram shows just how connected and yet vulnerable the whole system is.
Optical Cable Undersea