I think most people aren't aware of the history of AAA protocols in the iETF. 
 This message summarizes relevant documents in the area, and makes an appeal to 
the WG to remove the document as a WG document.

  RADIUS was standardized in 2000 in RFC 2058, after years of WG discussion.  
The original protocol goes back to 1993, unlike the TACACS+ draft, which was 
submitted in 1997.

  Diameter was standardized in 2003 in RFC 3588, again after years of WG 
discussion.  TACACS+ was never considered by the IETF as an AAA protocol.

  The IETF created a process to specify requirements for AAA protocols.  This 
process is documented in RFC 2989 [1] (2000), which had about 20 authors from 
all major networking companies at the time.  It solicited submissions, and 
established a panel to evaluate the submissions.  The results are documented 
inRFC 3127 [2] (2003).  TACACS+ was not even considered, as it did not meet the 
requirements set out in RFC 2989.

  What is happening here is that a single WG is re-visiting a multi-year 
process which involved dozens of experts in the area.  A process which 
established IETF consensus.  A process which was started almost two decades 
ago, and finished 13 years ago.

 While RFC 2989 and RFC 3127 are "informational", they are only informational 
because they do not document a protocol design.  They do, however, document 
IETF consensus.

  Standardizing a new AAA protocol without IETF-wide discussion means we're 
ignoring the requirements of RFC 2989, and discarding the results shown in RFC 
3127.

  Standardizing TACACS+ is like a single WG standardizing IPv8 on it's own, 
after decades of work on IPv6, without achieving wider IETF consensus, or even 
updating the WG charter.  It's one WG doing a complete end-run around IETF 
consensus.

  The document draft-ietf-opsawg-tacacs-00.txt *explicitly* describes itself as 
an AAA protocol in it's abstract.  Despite the authors stating it is for 
"device administration", that phrase *does not appear in the document*.  
Despite claims that it is not an AAA protocol, the document itself claims 
TACACS+ is an AAA protocol.  The document discusses user authentication, 
authorization, and accounting, in a manner which overlaps 100% with RADIUS.

  In fact, RADIUS has more capability than TACACS+.  RADIUS is standardized to 
transport many more attributes which describe hundreds of possible pieces of 
information.  The TACACS+ document documents little more than the base 
protocol, and a less than 30 kinds of information it can transport.

  The TACACS+ functionality therefore *explicitly* overlaps 100% with RADIUS.  
It is explicitly *not* "device authorization".  It is uniformly inferior to 
RADIUS in functionality and capability.  It meets none of the requirements set 
out in RFC 2989, and wasn't even considered in RFC 3127.

  The only *technical* capability that TACACS+ has which RADIUS doesn't is 
"device administration".  Perhaps what is meant here is "command 
authorization", in which individual administrator commands are authorized via 
the AAA protocol.  However, this capability is *not* documented in the draft, 
which means that any "device administration" remains a proprietary vendor 
extension, and entirely outside of the control of the IETF.


  The document overturns nearly two decades of IETF consensus.  It competes 
directly with an established IETF protocol.  It's functionality is explicitly 
inferior to RADIUS.  It's suggested use-case is entirely undocumented in the 
draft.

  Therefore, I ask the WG, chairs, and AD, to withdraw this document as a WG 
item.  It is entirely inappropriate for a standards track document.


[1] https://tools.ietf.org/html/rfc2989

[2] https://tools.ietf.org/html/rfc3127

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