Quick Reference Guide

Troubleshooting | 281
Monitoring 10 GE Interfaces
If a 10-Gigabit Ethernet (10-GE) interface does not reach a link up state, use the following steps:
1. Verify that you are using the correct XFP type. Optical specifications are available on the Dell Force10
website:
http://www.force10networks.com/products/specifications.asp
2. Reseat the XFP or swap it with a known good one.
3. If you are using an XFP, connect one single fiber cable (as opposed to a pair) linking the Tx and Rx of
the same XFP.
4. Cross-connect ports 49 and 50.
5. If you are using a CX4 module, adjust the preemphasis values with the
cx4-cable-length {long |
medium | short} command. Reducing the drive strength lowers the intensity (amplitude) of the signal
being driven to the other end.
Monitoring CPU and Memory Utilization
In SFTOS Version 2.5.1 and later, you can use the show process cpu command to monitor CPU
utilization. A high value (probably over 40%) for the ipMapForwardingTask indicates that packet
forwarding decisions are being made by the CPU and not by the hardware forwarding tables. This
condition normally occurs when the hardware receives packets with a destination address not found in the
hardware table. Hardware passes the packet up to the CPU. When the system finishes processing these
packets, or a route has been established for these destinations (the hardware table has been updated with
the new entries), the CPU response returns to normal.
In SFTOS Version 2.5.1 and later, you can use the
show memory command to monitor overall memory
utilization.
Software Forwarding
The process discussed above is often referred to as “software forwarding”, and sometimes “forwarded by
the CPU” or “CPU routing”, where the system receives a unicast packet whose destination IP address
cannot be resolved in the hardware, and so the packet is sent to the CPU to forward.
Note: The used and free memory amounts will be less than the total amount of memory. The show
memory command displays only memory allocated by the SFTOS kernel. It does not take into
account memory reserved for other functions, such as loading the system image.