4.1 Introduction

4.2 MIB Structure

4.2.1 Known Limitations

4.3 Node Tables

4.3.1 Configuration Table

dsx1ConfigTable 103

dsx1ConfigEntry 104

dsx1LineIndex 105

dsx1IfIndex 106

dsx1TimeElapsed 107

dsx1ValidIntervals 108

dsx1LineType 109

dsx1LineCoding 110

dsx1SendCode 111

dsx1CircuitIdentifier 112

dsx1LoopbackConfig 114

dsx1LineStatus 115

dsx1SignalMode 116

dsx1TransmitClockSource 117

dsx1Fdl 118

dsx1InvalidIntervals 119

dsx1LineLength 120

dsx1StatusLastChange 121

dsx1LineStatusChangeTrapEnable 122

dsx1LoopbackStatus 123

dsx1Ds1ChannelNumber 124

dsx1Channelization 125

4.3.2 Current Table

dsx1CurrentTable 127

dsx1CurrentEntry 128

dsx1CurrentIndex 129

dsx1CurrentESs 130

dsx1CurrentSESs 131

dsx1CurrentSEFSs 132

dsx1CurrentUASs 133

dsx1CurrentCSSs 135

dsx1CurrentPCVs 136

dsx1CurrentLESs 137

dsx1CurrentBESs 138

dsx1CurrentDMs 139

dsx1CurrentLCVs 140

4.3.3 Interval Table

dsx1IntervalNumber 142

dsx1IntervalValidData 143

4.3.4 Total Table

4.4 Trap Group

dsx1LineStatusChange 145

4.1 Introduction

This chapter describes the Natural MicroSystems implementation of the
Trunk MIB (RFC 2495). The organization of the tree, detailed descriptions of the nodes, and the available functions are also provided. Compliance to the Trunk MIB (RFC 2495) is also detailed.

All the boards in a chassis are represented as one managed node. Each trunk is represented by a numerical index, which is generated by sequentially numbering the trunks on all the boards.

RFC 2495 defines the near end and far end of each DS1 interface. The near end is the interface on the board that the agent is monitoring. The far end is the remote end of the trunk connected to that interface. Support is defined for the near end.

4.2 MIB Structure

The RFC 2495 MIB defines the following groups:

Group	Description
DS1 Near End Group	Contains configuration information about the DS1 interfaces, and statistics collected from the near end interface.
DS1 Far End Group	Optional and not supported.
Fractional Table	Optional and not supported.
Channel Mapping Table	Optional and not supported.
Trap Group	Enables a trap to be sent when the status of the interface changes.

4.2.1 Known Limitations

RFC 1573 defines an ifTable for all the interfaces in the system as part of MIB2. The ifTable is not accessible by the NMS SNMP agent. Therefore some portions of the RFC 2495 MIB are not supported.

The dsx1ChannelMappingTable is also not available.

The DS1 Near End Group consists of four tables:

Table	Description
Configuration	Contains information about each DS1 interface such as the number of bits per second that the circuit can reasonably carry, variety of Zero Code Suppression, and the vendor's circuit identifier.
Current	Contains statistics for the current 15-minute interval.
Interval	Contains statistics collected by each DS1 interface for the last 24 hours of operation. The past 24 hours are broken into 96 15-minute intervals. After 24 hours, the next interval pushes the oldest one out of the table.
Total	Contains the cumulative sum of the statistics for the period of time since this MIB was first started. Each field in this table contains the sum of the fields in the Current table for a particular interface.

The information in the Current table refreshes continuously. Every 15 minutes, the current table's contents are copied to the Interval table, and the sum of values from the Current table are added to the Total table. The Total table never resets, so the values are sums from the first time you started the DTM agent.

Figure 9 shows how the tables for DS1 relate:

Figure 9. 2495 MIB Table Relationships

Figure 9 shows a logical view of the tables for three DS1 interfaces. The Configuration table has an entry for each DS1 interface, which is identified by dsx1LineIndex. This index corresponds to the index in the other tables, such that all table entries with the same index number are for the same DS1 interface. Three DS1 interfaces are represented, so each table has three pages. Each column of values is started by an entry object.

Every 15 minutes, the values in the Current table are copied to the next available time slot (for example, if t1 was filled 15 minutes ago, t2 will be filled next) in the Interval table. The Current table values are added to the values in the Total table, which continue to add up until the agent is restarted.

If the Interval table is full when a new timeslot is added to the table, the last time slot (t97) is discarded, and the rest of the timeslots slide forward to make room for the new t1 timeslot.

Figure 10 shows a tree view of the sequence of objects in the Trunk MIB.

Figure 10. RFC 2495 MIB Tree

4.3 Node Tables

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

Managed Object
Syntax	The data type 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).
	· TruthValue	Integer value where 1 is True and 2 is False.
Access	The type of access allowed for this object. Options are:
	Read-only	This object can not be modified by SNMP.
	Read-write	You can modify this object with SNMP.
OID	Defines the path through the MIB tree to this object. The OID starts with p, which represents the OID for the Trunk MIB, and is 1.3.6.1.2.1.10.18.
Description	Describes the object.
Configuration	Describes how to configure the object.

4.3.1 Configuration Table

The following table summarizes each object in a dsx1ConfigEntry block of variables:

Object	Type	Description
dsx1LineIndex	Integer	Identifies a DS1 interface in this managed node.
dsx1IfIndex	Integer	Same as dsx1LineIndex.
dsx1TimeElapsed	Integer	Time of current measurement period.
dsx1ValidIntervals	Integer	Number of 15 minute measured intervals.
dsx1LineType	Integer	Type of DS1 interface.
dsx1LineCoding	Integer	Type of Zero Code Suppression for this interface.
dsx1SendCode	Integer	Type of code in the interface.
dsx1CircuitIdentifier	DisplayString	Transmission vendor's circuit identifier.
dsx1LoopbackConfig	Integer	Loopback configuration.
dsx1LineStatus	Integer	Interface status.
dsx1SignalMode	Integer	Circuit's signal mode.
dsx1TransmitClockSource	Integer	Source of the transmit clock.
dsx1Fdl	Integer	Describes the facilities data link.