Code review request: Drop obsolete RFC-791 markings for QoS markings

[Philip Prindeville]

Not sure what your point is: lots of things are marked "proposed standard" that are prevalent and ubiquitous.

PPP-IPCP and Telnet Linemode are "proposed standard" status, but you won't find an implementation of PPP or Telnet that omits either.

Of the network operators doing traffic shaping, more do QoS (DSCP) than do ToS.


On 2/18/11 3:04 PM, Iain Morgan wrote:
> According to www.rfc-editor.org, RFC 791 is not obsolete and is still a
> standard, although it is updated by RFC 1349. Whereas RFC 2474 is only a
> proposed standard.
>
> Is that correct?
>
> On Fri, Feb 18, 2011 at 16:03:44 -0600, Philip Prindeville wrote:
>> Here's the bug and proposed patch.  It's pretty trivial.
>>
>> https://bugzilla.mindrot.org/show_bug.cgi?id=1856
>>
>>
>> Quoting RFC-2474:
>>
>>      A replacement header field, called the DS field, is defined, which is intended to supersede the existing definitions of the IPv4 TOS octet [RFC791] and the IPv6 Traffic Class octet [IPv6]. [...] The structure of the DS field shown above is incompatible with the existing definition of the IPv4 TOS octet in [RFC791].
>>
>> and:
>>
>>      No attempt is made to maintain backwards compatibility with the "DTR" or TOS bits of the IPv4 TOS octet, as defined in [RFC791].
>>
>> Also note that the patch that was originally proposed (but not accepted as-is) for bug 1733 attempted to disallow user setting of the QoS bits, also in accordance with RFC-2474:
>>
>>      Correct operational procedure SHOULD follow [RFC791], which states: "If the actual use of these precedence designations is of concern to a particular network, it is the responsibility of that network to control the access to, and use of, those precedence designations."
>>
>>