BITS or BIT STRING

[Chris J. <cj...@cy...>]

Hello,

I have version 5.0.8 running as a agent with a custom MIB. The MIB has a BITS object 
defined similar to:

myStatus OBJECT-TYPE
   SYNTAX BITS {
     inTest (0),
     outTest (1),
     oneAlarm (2),
     twoAlarm (3),
     loopback (4),
     inFail (5),
     outFail (6),
     shutdown (7)
   }
   MAX-ACCESS read-only
   STATUS current
   DESCRIPTION
     "The latched status of the device."
   ::= { status 1 }

The code uses 'ASN_BIT_STR' to encode the variable. I can see the MIB element with:

  $ snmpget -c enterprise 10.10.10.133 myStatus.0
  MY-MIB::myStatus.0 = BITS: 00

A commercial SNMP management product is having trouble viewing the MIB element. The 
feedback from the support person is (and quoting):

   "BITS is a mib construct that maps onto an OCTET STRING data type in
    the SNMP PDU.
    BIT STRING is not a mib construct. It is an actual data type that has
    the same size as an INTEGER, but the SNMP PDU actually carries this as a
    special type."

We were also told this is in the RFCs but I cannot find any reference to 'BIT STRING' 
only BITS. Also I can only find 'ASN_BIT_STR' to encode the variable.

I would like to know if more than one way exists to encode BITS and if so where I can 
find the specific RFCs.

Regards

-- 
  Chris Johns, cjohns at cybertec . com . au