Subject: Re: <draft-ietf-disman-remops-mib-06.txt>

From: Alan Luchuk <[email-masked]>
Date: Mon, 16 Aug 1999 15:59:28 -0400 (EDT)

>> >> The HostAddress textual convention is specified like this:
>> >>
>> >>    HostAddress ::= TEXTUAL-CONVENTION
>> >>       STATUS  current
>> >>       DESCRIPTION
>> >>           "The textual convention for specifying a host
>> >>           address.  The type of address can be determined
>> >>           by examining the value of the preceding
>> >>           HostAddressType object:
>> >>
>> >>              HostAddressType   OCTETs    ADDRESS TYPE
>> >>                 none(0)         0        not specified
>> >>                 dnsName(1)      1-255    DNS name
>> >>                 ipv4(2)         4        ipv4
>> >>                 ipv6(3)         16       ipv6"
>> >>       SYNTAX OCTET STRING (SIZE (0..255))
>> >>
>
>What was it about the DESCRIPTION text that led to the conclusion that
>the user interface would use hex notation for ipv4 or ipv6 addresses?
>Why wouldn't that same logic lead one to believe that DNS names would
>be entered in hex?  :-)

The description clause describes, if not specifies, the number of
octets for each of the address types.  Specifically, for the IPv4
address type, the description says the length of HostAddress octet
string is 4 octets.  

The only way I can think of to encode an IPv4 address in a 4-octet 
octet string is to use the hex form.  Even the shortest human-friendly 
textual representation of a dotted-decimal IPv4 address is 7 octets 
(e.g.,  0.0.0.0), and the longest is 15 octets (255.255.255.255).
So the only way I can see to encode the IPv4 addresses in a 4-octet
string is to convert each integer (0-255) to it's corresponding hex 
value and stuff each integer into a single octet of the 4-octet 
string.

Please educate me:  what have I overlooked?

Regards,
--Alan

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 Alan Luchuk       SNMP Research, Inc.                 Voice:  +1 423 573 1434
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---

From: Bob Natale <[email-masked]>
Date: Mon, 16 Aug 1999 16:22:47 -0400

At 8/16/99:03:59 PM, Alan Luchuk wrote:

Hi Alan,

 >Please educate me:  what have I overlooked?

The difference between representation and encoding, I suppose.

Dec:  255.255.255.255  (unsigned)
       -1.-1.-1.-1      (signed...not applicable to IP addresses)
Hex:  FF.FF.FF.FF
Bin:  11111111.11111111.11111111.11111111

Are all representations of the same four-octet value.

Cordially,

BobN
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