Quick Reference Guide

350 | Quality of Service (QoS) Commands
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Policy Type Out
Incompatibilities Bandwidth (all forms), Shape Peak
mark cos
This command marks all packets for the associated traffic stream with the specified class of service
value in the priority field of the 802.1p header. If the packet does not already contain this header, one is
inserted.
Syntax
mark cos 0-7
The cos value is an integer from 0 to 7.
Default
1
Mode
Policy Class (The prompt is “(Config-policy-classmap)#”)
Policy Type
In
mark ip-dscp
This command marks all packets for the associated traffic stream with the specified IP DSCP value.
Syntax
mark ip-dscp dscpval
The dscpval value is specified as either an integer from 0 to 63, or symbolically through one of the
following keywords: af11, af12, af13, af21, af22, af23, af31, af32, af33, af41, af42, af43, be,
cs0, cs1, cs2, cs3, cs4, cs5, cs6, cs7, ef.
The Assured Forwarding (AF) and Best Effort (BE) codepoints are described in RFC 2597. The Class
Selector (CS) code points are defined in RFC 2474. The Expedited Forwarding (EF) codepoint is
described in RFC 2598.
Class selector DSCPs (CS0 through CS7) are values that are backward-compatible with IP precedence.
When converting between IP precedence and DSCP, match the three most significant bits. For example
cs5 is 101000, which is 0x28 (40 decimal in the table below.
Table 20-23 on page 350 shows an example of the mapping of numeric values to keywords. Note that
these numbers are base10 while the RFC refers to these in binary. For example, ef is shown below as
46, which the RFC specifies as 101110.
Table 20-23. Mapping of DSCP Keywords to Numerical Codepoints
DSCP Keywords Numeric Codepoints
AF11 10
AF12 12
AF13 14
AF21 18