RFC 2474: Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers

Publisher

IETF / RFC Editor

URL

https://www.rfc-editor.org/rfc/rfc2474.html

Published

1998-12-01

Updated

unknown

Accessed

2026-09-24

HTTP status

200

License

IETF Trust Legal Provisions (BCP 78/79); no-redistribution; short excerpts and locators only

Source notes citing this source

• DS domain boundary nodes must ensure that traffic entering the domain carries codepoints appropriate to the traffic and the domain, re-marking it where necessary. in context
• DSCP values of the form xxx000 are reserved as Class Selector codepoints for backward compatibility with IP Precedence. in context
• The recommended codepoint for the Default PHB is 000000. in context
• The DS field uses six bits as the DSCP and replaces the IPv4 TOS octet and the IPv6 Traffic Class octet. in context
• Seeing DSCP 0 at the far end of a call that crossed the public Internet or another provider's domain does not by itself show the near-end endpoint failed to mark; markings must be checked hop by hop starting at the sender's access port. inferred in context
• The DS field replaces the IPv4 TOS octet and the IPv6 Traffic Class octet, and six bits of it carry the DSCP that selects the per-hop behaviour at each node. in context
• RFC 2474 permits nodes to rewrite the DS field as needed to provide a desired local or end-to-end service, so a changed DSCP at a downstream hop is standards-conformant behaviour, not necessarily a fault. in context
• Packets received with an unrecognized codepoint SHOULD be forwarded as if marked for the Default (best-effort) behaviour, whose recommended codepoint is 000000. in context

Cite this source record

APA

WarmTransfer. (1998, December 1). RFC 2474: Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers. WarmTransfer. https://warmtransfer.net/knowledge/sources/rfc-2474-ds-field

BibTeX

@misc{warmtransfer-rfc-2474-ds-field,
  title  = {RFC 2474: Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers},
  author = {{WarmTransfer}},
  year   = {1998},
  url    = {https://warmtransfer.net/knowledge/sources/rfc-2474-ds-field},
  note   = {IETF / RFC Editor, accessed 2026-09-24}
}