doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 1 MIB Attribute Recommendations Date: Authors:
doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 2 MIB Background MIB is Management Information Base Purpose is to manage STAs and entities within STAs to allow proper and useful interoperation in a wireless network Such management is provided by interaction between entities to provide status and exert control –This is management interaction, not functional interaction provided by primitives –MIB attributes (a.k.a. “objects” or “variables”) provide an implicit interface between entities through read (“GET”) and write (“SET”) operations
doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 3 Uses of MIB attributes Read and Write –One or more entities may read an attribute –At most one entity shall write an attribute (multiple writers creates interlock uncertainty) –The entity to which the attribute applies may or may not write it Static and Dynamic –Dynamic attributes can be written while STA in in operation, affecting management changes –Static attributes are not written during operation Not local variables –Attributes accessed solely within the entity do not provide any management function. They are an implementation issue to ensure the entity’s state-based behaviors conform to the Standard. Such variables are inappropriate in the MIB.
doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 4 Types of MIB attributes Three types: –Capability: Static, initialized by entity as part of instantiation, read by other entities –Status: Dynamic, written by the entity to expose current conditions to reading entities –Control: Dynamic, written by other entities to control the entity’s manageable behaviors The definition and described usage of each attribute should be clear about its type, and which entities use the interaction for read and write Consider discussion about how and when changes to dynamic attributes are allowed/caused, and affect of the change
doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 5 Derivation of attribute types Read by other entity(ies) Written by other entity(ies) Read by applicable entity CapabilityControl Written by applicable entity StatusNot used
doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 6 Examples of types Capability – dot11CFPollable, dot11ManufacturerID, xxxImplemented, dot11RadioMeasurementCapable?, dot11ChannelAgilityPresent?, dot11RRMMeasurementPilotCapability? Status – xxxCount, xxxSelected, xxxEnabled, xxxSupported Control – dot11RTSThreshold, dot11ShortRetryLimit, dot11LongRetryLimit, dot11FragmentationThreshold, dot11PrivacyInvoked, dot11WEPDefaultKeyID, dot11CurrentFrequency
doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 7 Examples of Local Variables Local variables (currently not in MIB) – NAV, used_time, admitted_time, aXxxXxx (e.g. aSlotTime), CW, SSRC, SLRC Local variables (shouldn’t be in MIB) – dot11EDCATable, dot11EDCATableCWmin, etc. (for non-AP STA), dot11PowerManagementMode, dot11RRMNeighborReportTable, dot11BeaconPeriod -- Many of these could be controversial
doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 8 Dataflows for MIB attributes Not recommended to pass copies of MIB attribute values between entities –Have each entity read the value –Avoids duplicate “copies” that can be incorrect, or at least out-of- synch with the master –Corollary: Don’t pass MIB attribute values in primitives’ parameters Not more than one writer for any given attribute –Thus, control attributes are controlled by only one outside entity –Multiple entities can have control only by requesting writes through a single coordinating entity
doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 9 Dataflow example for “dot11XCapable”
doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 10 Dataflow example for “dot11XCapable”
doc.: IEEE /0427r1 Submission April 2009 Mark Hamilton, Polycom, Inc. Slide 11 Dataflow example for “dot11XCapable”