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 [RFC8126], a pool of 16 codepoints (Pool 2) to be reserved for experimental or Local Use (EXP/LU) as defined in [RFC8126], 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 [RFC8436]. The pools are defined in the following table (where 'x' refers to either '0' or '1').
Registries included below
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 |
Standards Action
Name | Value (Binary) | Value (Decimal) | Reference |
---|---|---|---|
CS0 | 000000 | 0 | [RFC2474] |
CS1 | 001000 | 8 | [RFC2474] |
CS2 | 010000 | 16 | [RFC2474] |
CS3 | 011000 | 24 | [RFC2474] |
CS4 | 100000 | 32 | [RFC2474] |
CS5 | 101000 | 40 | [RFC2474] |
CS6 | 110000 | 48 | [RFC2474] |
CS7 | 111000 | 56 | [RFC2474] |
AF11 | 001010 | 10 | [RFC2597] |
AF12 | 001100 | 12 | [RFC2597] |
AF13 | 001110 | 14 | [RFC2597] |
AF21 | 010010 | 18 | [RFC2597] |
AF22 | 010100 | 20 | [RFC2597] |
AF23 | 010110 | 22 | [RFC2597] |
AF31 | 011010 | 26 | [RFC2597] |
AF32 | 011100 | 28 | [RFC2597] |
AF33 | 011110 | 30 | [RFC2597] |
AF41 | 100010 | 34 | [RFC2597] |
AF42 | 100100 | 36 | [RFC2597] |
AF43 | 100110 | 38 | [RFC2597] |
EF | 101110 | 46 | [RFC3246] |
VOICE-ADMIT | 101100 | 44 | [RFC5865] |
Standards Action
Name | Value (Binary) | Value (Decimal) | Reference |
---|---|---|---|
LE | 000001 | 1 | [RFC8622] |
RFC Required
The registrations are identical for IPv4 and IPv6.
Binary | Keyword | Reference |
---|---|---|
00 | Not-ECT (Not ECN-Capable Transport) | [RFC3168] |
01 | ECT(1) (ECN-Capable Transport(1))[1] | [RFC3168][RFC Errata 5399] |
10 | ECT(0) (ECN-Capable Transport(0)) | [RFC3168] |
11 | CE (Congestion Experienced) | [RFC3168] |
[1] |
ECT(1) is for experimental use only [RFC8311, Section 4.2] |