Brocade TurboIron 24X Series Configuration Guide - Manual (Page 1070)

1036 Brocade TurboIron 24X Series Configuration Guide
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Classification
• Layer 3 Differentiated Service codepoint (DSCP) – This is the value in the six most significant
bits of the IP packet header 8-bit DSCP field. It can be a value from 0 – 63. These values are
described in RFCs 2472 and 2475. The DSCP value is sometimes called the DiffServ value.
The device automatically maps a packet's DSCP value to a hardware forwarding queue. Refer
to
“Viewing QoS settings” on page 1049".
• ACL keyword – An ACL can also prioritize traffic and mark it before sending it along to the next
hop. This is described in the ACL chapter in the section
“QoS options for IP ACLs” on page 923.
Given the variety of different criteria, there are multiple possibilities for traffic classification within a
stream of network traffic. For this reason, the priority of packets must be resolved based on which
criteria takes precedence. Precedence follows the scheme illustrated in
Figure 127
Determining the trust level of a packet’
Figure 127 illustrates how the device determines the trust level of a packet.
FIGURE 127 Determining a packet trust level