RFC中的「過時」和「更新」有什麼區別？

Question

的rfc-editor說

• 「淘汰了XXXX」 是指這一個替代其他RFC。
• 「更新xxxx」是指此更新但不能替代的其他RFC。

但是這引發了一個問題......爲什麼RFC更新另一個RFC而不更換它？

是否「更新」是指一些較早的信息在舊的RFC矛盾，但其他信息仍然是標準？這似乎很奇怪。

Answer 1

「更新xxxx」只是將定義添加到現有RFC中。現有RFC的內容不被新的RFC無效，仍需要實現的協議。例如，如果沒有必要重新定義完整的協議，但需要一些說明。

「過時xxxx」是一個協議的完整redefinitio。如果沒有其他原因，沒有必要爲你閱讀廢棄RFC理解/正確執行協議。

Answer 2

術語更新和淘汰了用於通過RFC 2223定義，但它是由RFC 7322，其沒有明確地定義這些術語過時。

我覺得早前的RFC定義做了這些方面的一個好工作。

RFC 2223 —淘汰了：1543，1111，825

的RFC 2223，1543和1111，這是所有重要的 「指令到RFC作者」，定義了這些術語作爲他們的 「關係到其他RFC」。 RFC 825是一個非常早期的版本，並沒有明確的條款。

RFC 2223 — 6. Relation to other RFCs

6. Relation to other RFCs 

    Sometimes an RFC adds information on a topic discussed in a previous 
    RFC or completely replaces an earlier RFC. There are two terms used 
    for these cases respectively, Updates and Obsoletes. A document that 
    obsoletes an earlier document can stand on its own. A document that 
    merely updates an earlier document cannot stand on its own; it is 
    something that must be added to or inserted into the previously 
    existing document, and has limited usefulness independently. The 
    terms Supercedes and Replaces are no longer used. 

    Updates 

     To be used as a reference from a new item that cannot be used 
     alone (i.e., one that supplements a previous document), to refer 
     to the previous document. The newer publication is a part that 
     will supplement or be added on to the existing document; e.g., an 
     addendum, or separate, extra information that is to be added to 
     the original document. 

    Obsoletes 

     To be used to refer to an earlier document that is replaced by 
     this document. This document contains either revised information, 
     or else all of the same information plus some new information, 
     however extensive or brief that new information is; i.e., this 
     document can be used alone, without reference to the older 
     document. 

     For example: 

     On the Assigned Numbers RFCs the term Obsoletes should be used 
     since the new document actually incorporate new information 
     (however brief) into the text of existing information and is 
     more up-to-date than the older document, and hence, replaces it 
     and makes it Obsoletes. 

    In lists of RFCs or the RFC-Index (but not on the RFCs themselves) 
    the following may be used with early documents to point to later 
    documents. 

    Obsoleted-by 

     To be used to refer to the newer document(s) that replaces the 
     older document. 

    Updated-by 

     To be used to refer to the newer section(s) which are to be added 
     to the existing, still used, document. 

RFC 7322 —淘汰了：2223

RFC 7322沒有定義的RFC 「相對於其他的RFC」 像早期的RFC一樣。

我只找到幾個提到的術語：

• https://tools.ietf.org/html/rfc7322#section-4.1.4

  4.1.4. Updates and Obsoletes 
  
      When an RFC obsoletes or updates a previously published RFC or RFCs, 
      this information is included in the document header. For example: 
  
       "Updates: nnnn" or "Updates: nnnn, ..., nnnn" 
  
       "Obsoletes: nnnn" or "Obsoletes: nnnn, ... , nnnn" 
  
      If the document updates or obsoletes more than one document, numbers 
      will be listed in ascending order. 
  

• https://tools.ietf.org/html/rfc7322#section-4.1。

  4.1. First-Page Header 
  
      Headers will follow the format described in "RFC Streams, Headers, 
      and Boilerplates" [RFC5741] and its successors. In addition, the 
      following conventions will apply. 
  

RFC 5741提及，這是由RFC 7841過時。它描述了RFC「與其他RFC的關係」的標題格式，但它僅指RFC 7322。

RFC 7841 — header format for an RFCs "Relation to other RFCs"

... 

[<RFC relation>:<RFC number[s]>] Some relations between RFCs in the 
    series are explicitly noted in the RFC header. For example, a new 
    RFC may update one or more earlier RFCs. Currently two 
    relationships are defined: "Updates" and "Obsoletes" [RFC7322]. 
    Variants like "Obsoleted by" are also used (e.g, in [RFC5143]). 
    Other types of relationships may be defined by the RFC Editor and 
    may appear in future RFCs.