RFC 6790, "The Use of Entropy Labels in MPLS Forwarding", November 2012Source of RFC: mpls (rtg)
Errata ID: 3431
Status: Held for Document Update
Publication Format(s) : TEXT
Reported By: Jeff Wheeler
Date Reported: 2012-12-16
Held for Document Update by: Adrian Farrel
Section 5.2 says:
This is an optional, transitive BGP attribute of value 28.
It should say:
This is an optional, transitive BGP Attribute having Attribute Type Code 28, length 0, and no data.
"Value" is (slightly) confusing in this context. The text should also explicitly specify that there isn't Attribute Data and thus the length will be 0.
Ambiguity on this matter may lead implementations to utilize the data field in some unforeseen way. Other implementations may then reject the attribute, applying general attribute processing rules, with an Attribute Length Error (RFC 4271 S6.3 paragraph 4.)