3.1 Introduction

3.2 Chassis Representation

3.3 MIB Structure

3.3.1 Introduction

3.3.2 Chassis Configuration Table

3.3.3 Bus Segment Table

3.3.4 Board Access Table

3.3.5 Board Table

3.3.6 Traps Group

3.4 Using the Chassis MIB

3.4.1 Traps

3.4.2 Hot Swap

3.4.3 Board Status

3.4.4 Linking to the Trunk MIB

3.5 Node Tables

chassMIBRevision 51

chassConfig 52

chassType 53

chassDescr 54

chassSegmentBusCount 55

busSegmentTable 56

busSegmentEntry 57

busSegmentIndex 58

busSegmentType 59

busSegmentDescr 60

busSegmentSlotsOccupied 61

chassBoardAccess 62

slotTable 63

slotEntry 64

slotBusSegmentIndex 65

slotIndex 66

slotBoardIndex 67

slotStatus 68

chassBoard 70

chassBoardCount 71

chassBoardTrapEnable 72

boardTable 73

boardEntry 74

boardIndex 75

boardBusSegmentType 76

boardBusSegmentNumber 77

boardSlotNumber 78

boardModel 79

boardModelText 81

boardFamilyId 83

boardFamilyNumber 84

boardDescr 85

boardStatus 86

boardCommand 87

boardTrunkCount 88

boardRevision 89

boardSerialNumber 90

boardManufDate 91

boardStatusLastChange 92

boardStatusChangeTrapEnable 93

3.1 Introduction

This chapter provides a detailed description of the structure and use of the NMS Chassis MIB. Section 3.5 provides a list of managed objects contained within the NMS Chassis MIB, ordered according to the MIB structure described in Figure 8.

3.2 Chassis Representation

The Chassis MIB represents the boards installed in an NMS chassis. Boards and lines (trunks) are numbered sequentially, and are assigned to tables.

The Chassis agent detects each NMS board that has both been registered to OAM (agmon for CT Access 3.x) and has booted correctly, and monitors its operational status. The board model, type, revision, bus segment and slot, and logical ID are represented. Removing or inserting a board (hot swap) is also monitored, and traps are sent if the status of a board changes.

3.3 MIB Structure

This section describes the tables in the Chassis MIB, and the relationship between the tables.

3.3.1 Introduction

The Chassis MIB represents a chassis as single managed node that consists of the buses, slots, and devices installed in a chassis. There are five major tables within the Chassis MIB:

Table	Description
Chassis Configuration	Provides information about the chassis.
Bus Segment	Provides information about the bus segments in this chassis.
Board Access by bus slot	Provides an index into the Bus Segment table and the Board table.
Board	Provides information about each board.
Board Access by backplane	Not implemented. (Reserved for future use.)

Figure 7 shows how the tables in the Chassis MIB are related to one another:

Figure 7. Chassis MIB Table Relations

Figure 7 shows that a busSegmentCount value of 5 in the Chassis Configuration table results in five entries in the Bus Segment table. Bus segment 3 has four occupied slots, so there are four entries in the Board Access table for that bus segment. Each entry in the Board Access table has a boardIndex field, whose value is an index into the Board table for that board.

Two fields in the Board table match parts of dsx1CircuitIdentifier in the Trunk MIB. For more information about how the Chassis MIB and Trunk MIB can be used together, see Section 3.4.

The sequence of objects in the Chassis MIB (with relative OIDs for table objects) is shown in Figure 8:

Figure 8. Chassis MIB Objects

3.3.2 Chassis Configuration Table

The Chassis Configuration table contains the following information:

• Type of chassis

• Description

• Number of bus segments within the chassis

Information about each bus segment, such as type of bus segment, description, and number of occupied slots, is contained within an object block that makes up the Bus Segment table. The objects in this table are under the chassConfig table of the Chassis MIB, as shown in Figure 8. Values are assigned to these objects by the NMS Chassis agent.

The objects in the Chassis Configuration table are:

Object	Description
chassConfig	Top of the table.
chassType	Chassis type.
chassDescr	Description of the chassis.
chassSegmentBusCount	Number of bus segments within the chassis.

3.3.3 Bus Segment Table

The Bus Segment table contains information about each bus segment, such as type of bus segment, description, and number of occupied slots. There can only be one ISA bus segment, but there can be many PCI (or compact PCI) bus segments.

Each busSegmentEntry object is identified by a busSegmentIndex object, whose value is assigned by the NMS Chassis agent.

busSegmentEntry objects are added to the table when a board is added to a new bus segment. If all boards are extracted, that bus segment will be deleted from the table.

Note: ISA boards are not supported by CT Access version 4.0 and later.

The objects in the Bus Segment table are:

Object	Description
busSegmentTable	Starts the Bus Segment table.
busSegmentEntry	Starts a row of the Bus Segment table.
busSegmentIndex	Number of this row in the Bus Segment table.
busSegmentType	Bus type.
busSegmentDescr	Describes the bus segment.
busSegmentSlotsOccupied	Number of occupied slots in this bus segment.

3.3.4 Board Access Table

The Board Access table simplifies access to the Board table's variables. The Board table can be sequentially accessed by using a series of get-next commands starting from the beginning of the table. But this type of access is not convenient for all types of queries. For example, an application may be interested in the trunk count of all boards on PCI segment 2. Using get-next commands, the application must traverse the entire table in order to ensure that all boards are accounted for. With the index table, the application only needs to find the first entry with the busSegmentNumber that matches PCI segment 2, and the rest of that segment's boards will be listed next.

The Board Access table provides an index into the Board table that allows an application to directly access specific boards using get commands, based on the board's bus type, bus segment number, or logical slot number.

Object	Action
Bus Type	Examine the Bus Segment table to find the bus segment type you are interested in. Look for that entry's busSegmentIndex value in the Board Access table, and use each matching entry's slotBoardIndex value to find the entry in the Board table.
Bus Segment Number	Find the matching slotBusSegmentNumber in the Board Access table, and use that entry's slotBoardIndex value to find the entry in the Board table.
Slot Number	Find the slotIndex value for a chosen bus segment, and use that row's boardIndex value to index into the Board table.

The objects in the Board Access/Slot table are:

Object	Description
chassBoardAccess	Starts the Board Access table.
slotTable	Starts the rows of the Board Access table.
slotEntry	Starts a row in the Board Access table.
slotBusSegmentIndex	Number of the bus segment this board is in.
slotIndex	Logical slot index of a board in the bus segment.
slotBoardIndex	Index into the Board table for this bus segment.
slotStatus	Status of the slot (hot swap status).

3.3.5 Board Table

Each boardEntry object in the Board table contains information about a single board in the chassis. This group of objects includes the board model, a textual description of the board model, a family identifier, the board's status, the trunk count, the board revision, the board's serial number, and the board's date of manufacture. Each boardEntry is identified by the boardIndex object, whose value is assigned by the NMS Chassis agent. New boardEntry objects are added to this table and configured for OAM (or added in agmon for CT Access 3.x) when a board is added to the chassis.

Entries in the Board table are removed if a board physically is extracted. If a board is inserted, a new entry will be added to the Board table using the next free index. Whenever a board is inserted or extracted, a trap is sent (if traps have been enabled).

The objects in the Board table are:

Object	Description
chassBoard	Start of the board descriptions.
chassBoardCount	Number of boards in the chassis.
boardTable	Starts the Board table.
boardEntry	Starts a row of the Board table.
boardIndex	Number of this row in the Board table.
boardBusSegmentType	Type of bus segment.
boardBusSegmentNumber	Number of the bus segment this board is in.
boardSlotNumber	Number of the slot.
boardModel	Model of this board (numeric).
boardModelText	Model of this board (textual).
boardFamilyId	Family of the board.
boardFamilyNumber	Logical number of the board.
boardDescr	Board description.
boardStatus	Board status (online or offline).
boardTrunkCount	Number of trunks on this board.
boardRevision	Board revision.
boardSerialNumber	Board serial number.
boardManufDate	Date the board was manufactured.
boardStatusLastChange	When the status of the board last changed.
boardStatusChangeTrapEnable	Determines if boardStatusLastChange traps will be generated.

3.3.6 Traps Group

This is used by the agent to specify trap information. It has a valid Object Identifier, but does not contain usable information for developers.

3.4 Using the Chassis MIB

This section describes how to use the values in the Chassis MIB and provides other information common to more than one table.

3.4.1 Traps

Traps can be enabled to report a change in board status. The boardStatusChangeTrapEnable object in the Board table can be set to enable or disable traps. Traps must also be configured. See Chapter 2 for more information about configuring traps.

3.4.2 Hot Swap

Extracting a board causes the entry for that board in the Board table to be removed. If all the boards in a bus segment are extracted, that bus segment entry will be removed from the Bus Segment table. If the removed entry creates a
non-contiguous numerical sequence, that number will be used the next time a board is inserted (and recognized by the agent). The Hot Swap software sees an inserted board before the agent has access to it.

Note: Hot Swap only works with the CompactPCI bus. The Hot Swap functionality described above is available only if the Hot Swap Manager is running. For more information on running the Hot Swap Manager, refer to the OAM System User's Manual. (If using CT Access 3.x, refer to the Hot Swap Developer's Manual.)

3.4.3 Board Status

Board status differs depending on which version of CT Access you are using.

• When using CT Access 3.x, two board status objects are used: boardStatus in the Board table, and slotStatus in the Board Access by slot table. boardStatus provides a simple (online, offline, or pending) message, and slotStatus gives a finer grain value, the Hot Swap state. For more information about Hot Swap states, see the OAM System User's Manual. (If using CT Access 3.x, refer to the Hot Swap Developer's Manual.)

• In CT Access 4.0 (or later), boardStatus and slotStatus are identical, and their functionality is equivalent to that of slotStatus under CT Access 3.x.

The two objects tie together by an index value. boardIndex in the Board table matches the slotBoardIndex in the Board Access by slot table.

3.4.4 Linking to the Trunk MIB

dsx1CircuitIdentifier in the Trunk MIB (RFC 2495) contains the name of the board that the line is on, as well as a board number and trunk number. The board text portion maps to the boardFamilyId in the Chassis MIB, and the board number maps to the boardIndex in the Chassis MIB (both objects are in the Board table).

For example:

dsx1CircuitIdentifier = AG_Dual_T1_02_01

boardModelText = AG_Dual_T1

boardFamilyNumber = 2

In this example, dsx1CircuitIdentifier says that the trunk is on an AG_Dual_T1 board, the family number is 2, and the trunk number is 1 (trunk number has no direct match in the Chassis MIB).

3.5 Node Tables

The following sections describe the objects in this MIB. A typical object description includes:

Managed Object
Syntax	The datatype of the object is shown. SNMP data types include:
	· Integer	16-bit signed.
	· DisplayString	ASCII text.
	· Gauge	Positive integer from 0 to 4294967295 (232 - 1).
	· Object	Another object type from this MIB.
	· TimeStamp	Positive integer from 0 to 4294967295 (232 - 1).
Access	The type of access allowed for this object. Options are:
	Read-only	This object can not be modified by SNMP.
	Read-write	SNMP can configure this object.
OID	The OID defines the path from the root to this object. All OIDs start with p, where p is is 1.3.6.1.4.1.2628.2.2 (the OID for the Chassis MIB).
Description	Describes the object.
Configuration	Describes how to configure the object.