[MIB-DOCTORS] Fw: Octet String as Index longer than 128 OIDs, 8021X-REV MIB issue

Hi Dan and Bert,

I am trying to resolve this issue to define a TC. Not sure it is workable. Can you help me to review the TC I proposed.

OctetStringInOIDEncoding ::= TEXTUAL-CONVENTION

DISPLAY-HINT "255t"

STATUS current

DESCRIPTION "This is a textual convention designed to represent

an octet string containing administrative

information, but encoded in the OBJECT IDENTIFIER

format.

Each sub-identifier must not exceed the value

2^32 - 1 (4294967295 decimal) [RFC2578] with 4

bytes space needed to store the value. An object

sub-identifier can hold 4 octets information, each

octet (8-bit byte). Therefore, encoding 4 octets

into a sub-identifier in the index field can reduce

the length of OIDs of the columar objects.

The purpose of this textual convention is to help

increase the maximum length of an OCTET STRING object

,as an index, to 256 octets long. Currently, the

sub-identifiers of an instance of a columar

object is limited 128 [RFC2578]. If using the

OCTET STRING object as the INDEX, the mximum length

of the OCTET STRING index will be limited less than

128. By encoding the OCTET STRING information into

OBJECT IDENTIFIER, the longer OCTET STRING can be used.

The encodeing rules is as following :

Octets are numbered by their position in one

sub-identifier, starting at zero. Position zero

is the high order (or left-most) byte in the

first sub-identifier of the list of

sub-identifiers. Position 3 is the low order

(or right-most) byte of the first sub-identifier

of the list of sub-identifers. Position 4 is

the high order byte in the second sub-identifier

of the list of sub-identifiers, and so on. When

the number of bytes is not a multipple of four,

then there will be remaining bytes in the final

sub-identifier. When a value of the octet string

is encoded into OID list format, the remaining

bytes, if any, of the final sub-identifier are

set to zero. The octet string values are grouped

four per sub-identifier (4-byte integer).

Encoding of 'n' octets string, numbered 0 to

(n - 1) octets string are in (n + 3) / 4

sub-identifier. And any remaining octets in the

last sub-identifier should be zero.

This textual convention should be only used for

the object as INDEX object(s) of a conceptual

table.

SYNTAX OBJECT IDENTIFIER (SIZE (1..64))

Thanks,

Frank

From: Frank Chao (fchao)
Sent: Monday, August 03, 2009 2:50 PM
To: 'Romascanu, Dan (Dan)'
Subject: Octet String as Index longer than 128 OIDs

Hi Dan,

Need your help to resolve this problem.

I am working on the .1X-REV MIB and have a problem as you have reviewed. One object is defined (1,,253) octet string and will be used as INDEX, apparently, the maximum OIDs length is more then 28 as standard specified. But people in the .1 security group still think that it is possible the length of the object could be 253 octet when people configured this object information. The original thought was to divide into 2 objects but after deep thinking, it is the same because they both will be in the index field. Do you have any experience about this or you have solution for this ?

Thanks a lot,

Frank