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                                                   Differentiated Services Field Codepoints (DSCP)

Last Updated
        2026-05-13

Note

 The Differentiated Services (Diffserv) architecture specifies use
 of the DS field in the IPv4 and IPv6 packet headers to carry one
 of 64 distict differentiated services field codepoint (DSCP) values.
 The codepoint space is divided into three pools for the purpose of
 codepoint assignment and management: a pool of 32 codepoints (Pool 1)
 to be assigned by Standards Action as defined in [RFC 8126], a pool of
 16 codepoints (Pool 2) to be reserved for experimental or Local Use
 (EXP/LU) as defined in [RFC 8126], and a pool of 16 codepoints (Pool 3)
 which are initially available for experimental or local use, but
 which should be preferentially utilized for standardized assignments
 if Pool 1 is ever exhausted. Pool 3 codepoints are now utilized for
 standardized assignments and are no longer available for experimental
 or local use, as specified by [RFC 8436]. The pools are defined in the
 following table (where 'x' refers to either '0' or '1').


Available Formats
        [IMG]
        XML [IMG]
        HTML [IMG]
        TXT

Registries Included Below

  • Differentiated Services Field Codepoints (DSCP)
       • DSCP Pool 1 Codepoints
       • DSCP Pool 3 Codepoints
  • ECN Field (Bits 6-7)

Differentiated Services Field Codepoints (DSCP)

Reference
        [RFC 2474][RFC 3260, Section 4]

Note

 See [RFC 9435] for considerations when assigning
 a new codepoint from the DSCP registry.


Available Formats
        [IMG]
        CSV

Pool Codepoint Space  Registration Procedure                    Note
1    xxxxx0          Standards Action
2    xxxx11          Experimental or Local Use Reserved for experimental or Local Use
3    xxxx01          Standards Action

  DSCP Pool 1 Codepoints

Registration Procedure(s)

               Standards Action


Reference
        [RFC 2474][RFC 3260, Section 4]

Available Formats
        [IMG]
        CSV

   Name     Value (Binary) Value (Decimal) Reference
CS0         000000         0               [RFC 2474]
CS1         001000         8               [RFC 2474]
CS2         010000         16              [RFC 2474]
CS3         011000         24              [RFC 2474]
CS4         100000         32              [RFC 2474]
CS5         101000         40              [RFC 2474]
CS6         110000         48              [RFC 2474]
CS7         111000         56              [RFC 2474]
AF11        001010         10              [RFC 2597]
AF12        001100         12              [RFC 2597]
AF13        001110         14              [RFC 2597]
AF21        010010         18              [RFC 2597]
AF22        010100         20              [RFC 2597]
AF23        010110         22              [RFC 2597]
AF31        011010         26              [RFC 2597]
AF32        011100         28              [RFC 2597]
AF33        011110         30              [RFC 2597]
AF41        100010         34              [RFC 2597]
AF42        100100         36              [RFC 2597]
AF43        100110         38              [RFC 2597]
EF          101110         46              [RFC 3246]
VOICE-ADMIT 101100         44              [RFC 5865]

  DSCP Pool 3 Codepoints

Registration Procedure(s)

               Standards Action


Reference
        [RFC 2474][RFC 3260, Section 4][RFC 8436]

Available Formats
        [IMG]
        CSV

Name Value (Binary) Value (Decimal) Reference
LE   000001         1               [RFC 8622]
NQB  101101         45              [RFC 9956]

ECN Field (Bits 6-7)

Registration Procedure(s)

             RFC Required


Reference
        [RFC 3168]

Note

 The registrations are identical for IPv4 and IPv6.


Available Formats
        [IMG]
        CSV

Binary               Keyword                                Reference
00     Not-ECT (Not ECN-Capable Transport)  [RFC 3168]
01     ECT(1) (ECN-Capable Transport(1))[1] [RFC 8311]; [RFC Errata 5399]; [RFC 9331]
10     ECT(0) (ECN-Capable Transport(0))    [RFC 3168]
11     CE (Congestion Experienced)          [RFC 3168]

                                                                       Footnote

[1] ECT(1) is for experimental use only [RFC 8311, Section 4.2]

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