HP StorageWorks 64 FW 07.00.00/HAFM SW 08.06.00 McDATA E/OS SNMP Support Manua - Page 384

SNMP Framework MIB D • Values greater than 255 are allocated to enterprise-specific Security Models. An enterprise-specific securityModel value is defined to be: enterpriseID * 256 + security model within enterprise. For example, the fourth Security Model defined by the enterprise whose enterpriseID is 1 would be 260. The eight bits allow a maximum of 255 (256-1 reserved) standards based Security Models. Similarly, they allow a maximum of 255 Security Models per enterprise. It is believed that the assignment of new securityModel values will be rare in practice because the larger the number of simultaneously utilized Security Models, the larger the chance that interoperability will suffer. Consequently, it is believed that such a range will be sufficient. In the unlikely event that the standards committee finds this number to be insufficient over time, an enterprise number can be allocated to obtain an additional 255 possible values. Note that the most significant bit must be zero; hence, there are 23 bits allocated for various Organizations to design and define non-standard securityModels. This limits the ability to define new proprietary implementations of Security Models to the first 8,388,608 enterprises. It is worthwhile to note that, in its encoded form, the securityModel value will normally require only a single byte since, in practice, the leftmost bits will be zero for most messages and sign extension is suppressed by the encoding rules. As of this writing, there are several values of securityModel defined for use with SNMP or reserved for use with supporting MIB Objects. They are as follows: 0 reserved for 'any' 1 reserved for SNMPv1 2 reserved for SNMPv2c 3 User-Based Security Model (USM) SnmpMessageProcessingModel Syntax INTEGER(0..2147483647) Status current D-4 E/OS SNMP Support Manual