Re: [Iot-directorate] Iotdir telechat review of draft-ietf-core-dev-urn-09

[Dave Thaler <[e-mail]>]

One comment below in response to Russ.  I will send my own review later today:

>    Section 3.2.1 says:

>

>       ... and a MAC address could be represented either with

>       uppercase or lowercase hexadecimal digits.

>

>    This is not allowed by the ABNF:

>

>       hexstring = 1*(hexdigit hexdigit)

>       hexdigit = DIGIT / "a" / "b" / "c" / "d" / "e" / "f"

>

>    If both cases are to be supported, the upper case letters need to be

>    added to the ABNF to permit them.



That is not correct.  It is already allowed by the ABNF.

RFC 5234 explains:



ABNF strings are case insensitive and the character set for these

      strings is US-ASCII.



   Hence:



         rulename = "abc"



   and:



         rulename = "aBc"



   will match "abc", "Abc", "aBc", "abC", "ABc", "aBC", "AbC", and

   "ABC".



      To specify a rule that is case sensitive, specify the characters

      individually.



   For example:



         rulename    =  %d97 %d98 %d99



   or



         rulename    =  %d97.98.99



   will match only the string that comprises only the lowercase

   characters, abc.



Dave