CODEWITHSUNDEEP
snmpmib
user1578656
user1578656

Reputation: 131

Should the MAX-ACCESS field of the index (key) of a MIB table always be not-accessible?

Is it a hard and fast rule to set the index of a MIB table to be not-accessible?

Upvotes: 2

Views: 7028

Answers (2)

Michael Kirkham
Michael Kirkham

Reputation: 1070

MAX-ACCESS for INDEX objects should always be not-accessible in SMIv2 modules, except in certain circumstances. Per RFC 2578 (Structure of Management Information Version 2) section 7.7(6):

Objects which are both specified in the INDEX clause of a conceptual row and also columnar objects of the same conceptual row are termed auxiliary objects. The MAX-ACCESS clause for auxiliary objects is "not-accessible", except in the following circumstances:

(1) within a MIB module originally written to conform to SMIv1, and later converted to conform to SMIv2; or

(2) a conceptual row must contain at least one columnar object which is not an auxiliary object. In the event that all of a conceptual row's columnar objects are also specified in its INDEX clause, then one of them must be accessible, i.e., have a MAX-ACCESS clause of "read-only". (Note that this situation does not arise for a conceptual row allowing create access, since such a row will have a status column which will not be an auxiliary object.)

Upvotes: 5

Ayushi Jha
Ayushi Jha

Reputation: 4023

A MAX-ACCESS can take any of the four values: read-only, read-write, write-only, not-accessible. From this source:http://www.tcpipguide.com/free/t_TCPIPMIBObjectsObjectCharacteristicsandObjectTypes-2.htm

Table 205: SNMP SMI Version 2 Max-Access Values

Max-Access Value       Description

read-create            Object can be read, written or created.

read-write             Object can be read or written.

read-only              Object can only be read.

accessible-for-notify  Object can be used only using SNMP notification (SNMP traps).

not-accessible         Used for special purposes.

Here is an example where values other than not-accessible are used: https://www.ietf.org/rfc/rfc4625.txt :

t11FcRouteStorageType OBJECT-TYPE
SYNTAX      StorageType
MAX-ACCESS  read-create
STATUS      current
DESCRIPTION
       "The storage type for this conceptual row.
       Conceptual rows having the value 'permanent' need not
       allow write-access to any columnar objects in the row."
   DEFVAL { nonVolatile }
::= { t11FcRouteEntry 12 }

More information can be found here: http://www.simple-times.org/pub/simple-times/issues/1-4.html

The ACCESS clause has been renamed to MAX-ACCESS in order to clarify that it specifies the maximum access which makes ''protocol sense'', and the values are ordered, from least to greatest, as follows: ''not-accessible'', ''read-only'', ''read-write'', ''read-create''. The ''read-create'' value is used for write-able objects in a conceptual row for which new instances can be created via network management. Another change is the recommended use of ''not-accessible'' for auxiliary objects (those objects defined in a table solely for use in identifying a conceptual row).

Upvotes: 7

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