McDATA 316095-B21 - StorageWorks Edge Switch 2/24 Manual page 495

An identifier that uniquely identifies a Message Processing Model of
Description
the Message Processing Subsystem within a SNMP Management
Architecture.
The values for messageProcessingModel are allocated as follows:
• Values between 0 and 255, inclusive, are reserved for
standards-track Message Processing Models and are managed by
the Internet Assigned Numbers Authority (IANA).
• Values greater than 255 are allocated to enterprise-specific
Message Processing Models. An enterprise
messageProcessingModel value is defined to be: enterpriseID *
256 + messageProcessingModel within enterprise
For example, the fourth Message Processing Model defined by the
enterprise whose enterpriseID is 1 would be 260. The eight bits allow
a maximum of 256 standards based Message Processing Models.
Similarly, they allow a maximum 256 Message Processing Models per
enterprise.
It is believed that the assignment of new messageProcessingModel
values will be rare in practice because the larger the number of
simultaneously utilized Message Processing Models, the larger the
chance that interoperability will suffer. 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 256 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 messageProcessingModels. This limits the ability to
define new proprietary implementations of Message Processing
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 essageProcessingModel
defined for use with SNMP. They are as follows:
0 reserved for SNMPv1
SNMP Framework MIB
SNMP Framework MIB
F
F-5