Reference Guide

S5000 Debugging and Diagnostics | 1023
Figure 57-8. Buffer Tuning Points
Deciding to tune buffers
Dell Networking 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.
Configuration changes take effect immediately and appear in the running configuration. Since 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.
Dell Networking OS Behavior: If you attempt to apply a buffer profile to a non-existent port-pipe, Dell networking
OS 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 stack-unit 2. Valid range of
port-set is <0-1>
CSF Unit 3
FP Unit 1
PHY
PHY
1
2
3
IDP Switch Lin
ks
F
ront-end Links