Reference Guide

Debugging and Diagnostics | 259
Deciding to Tune Buffers
Dell Force10 recommends exercising caution when configuring any non-default buffer settings, as tuning
can significantly affect system performance. The default values work for most cases.
As a guideline, consider tuning buffers if traffic is very bursty (and coming from several interfaces). In this
case:
• Reduce the dedicated buffer on all queues/interfaces.
• Increase the dynamic buffer on all interfaces.
• Increase the cell pointers on a queue that you are expecting will receive the largest number of packets.
Buffer Tuning Commands
To tune the buffers, use the following commands:
Configuration changes take effect immediately and appear in the running configuration. Because under
normal conditions all ports do not require the maximum possible allocation, the configured dynamic
allocations can exceed the actual amount of available memory; this is called oversubscription. If you
choose to oversubscribe the dynamic allocation, a burst of traffic on one interface might prevent other
interfaces from receiving the configured dynamic allocation, which causes packet loss.
Task Command Command Mode
Define a buffer profile for the FP queues.
buffer-profile fp fsqueue
CONFIGURATION
Define a buffer profile for the CSF queues.
buffer-profile csf csqueue
CONFIGURATION
Change the dedicated buffers on a physical 1G
interface.
buffer dedicated
BUFFER PROFILE
Change the maximum amount of dynamic buffers
an interface can request.
buffer dynamic
BUFFER PROFILE
Change the number of packet-pointers per queue.
buffer packet-pointers
BUFFER PROFILE
Apply the buffer profile to a CSF to FP link.
buffer csf linecard
CONFIGURATION
FTOS Behavior: If you attempt to apply a buffer profile to a non-existent port-pipe, FTOS displays the
following message. However, the configuration still appears in the running-config.
%DIFFSERV-2-DSA_BUFF_CARVING_INVALID_PORT_SET: Invalid FP port-set 2 for linecard 2. Valid
range of port-set is <0-1>