Subject: [tcpm] [Errata Verified] RFC5925 (4365)

From: RFC Errata System <[email-masked]>
Date: Wed, 16 Dec 2015 13:30:47 -0800 (PST)

The following errata report has been verified for RFC5925,
"The TCP Authentication Option". 

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You may review the report below and at:
http://www.rfc-editor.org/errata_search.php?rfc=5925&eid=4365

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Status: Verified
Type: Technical

Reported by: Joe Touch <[email-masked]>
Date Reported: 2015-05-12
Verified by: Martin Stiemerling (IESG)

Section: 7.6

Original Text
-------------
   TCP\\\\'s 4-bit data offset requires that the options end 60 bytes (15
   32-bit words) after the header begins, including the 20-byte header.
   This leaves 40 bytes for options, of which 15 are expected in current
   implementations (listed below), leaving at most 25 for other uses.
   TCP-AO consumes 16 bytes, leaving 9 bytes for additional SYN options
   (depending on implementation dependant alignment padding, which could
   consume another 2 bytes at most).

   o  SACK permitted (2 bytes) [RFC2018][RFC3517]

   o  Timestamps (10 bytes) [RFC1323]

   o  Window scale (3 bytes) [RFC1323]

Corrected Text
--------------
   TCP\\\\'s 4-bit data offset requires that the options end 60 bytes (15
   32-bit words) after the header begins, including the 20-byte header.
   This leaves 40 bytes for options, of which 19 are expected in current
   implementations (listed below), leaving at most 21 for other uses.
   TCP-AO consumes 16 bytes, leaving 5 bytes for additional SYN options
   (depending on implementation dependent alignment padding, which could
   consume another 2 bytes at most).

   o  SACK permitted (2 bytes) [RFC2018][RFC3517]

   o  Timestamps (10 bytes) [RFC1323]

   o  Window scale (3 bytes) [RFC1323]

   o  Maximum Segment Size (4 bytes) [RFC793]

Notes
-----
MSS was missing in the original text. New text includes MSS and updates numbers accordingly.

Also corrects a spelling error (dependant -> dependent), which is non-technical but included in the revised text.

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RFC5925 (draft-ietf-tcpm-tcp-auth-opt-11)
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Title               : The TCP Authentication Option
Publication Date    : June 2010
Author(s)           : J. Touch, A. Mankin, R. Bonica
Category            : PROPOSED STANDARD
Source              : TCP Maintenance and Minor Extensions
Area                : Transport
Stream              : IETF
Verifying Party     : IESG