ISDN-MIB

File: ISDN-MIB.mib (46030 bytes)

Imported modules

SNMPv2-SMI SNMPv2-TC SNMPv2-CONF
IF-MIB IANAifType-MIB RFC1213-MIB

Imported symbols

MODULE-IDENTITY NOTIFICATION-TYPE OBJECT-TYPE
Counter32 Gauge32 Integer32
DisplayString TruthValue TimeStamp
RowStatus TestAndIncr TEXTUAL-CONVENTION
MODULE-COMPLIANCE OBJECT-GROUP ifIndex
InterfaceIndex IANAifType transmission

Defined Types

IsdnSignalingProtocol  
TEXTUAL-CONVENTION    
  current INTEGER other(1), dss1(2), etsi(3), dass2(4), ess4(5), ess5(6), dms100(7), dms250(8), ni1(9), ni2(10), ni3(11), vn2(12), vn3(13), vn4(14), vn6(15), kdd(16), ins64(17), ins1500(18), itr6(19), cornet(20), ts013(21), ts014(22), qsig(23), swissnet2(24), swissnet3(25)

IsdnBasicRateEntry  
SEQUENCE    
  isdnBasicRateIfType INTEGER
  isdnBasicRateLineTopology INTEGER
  isdnBasicRateIfMode INTEGER
  isdnBasicRateSignalMode INTEGER

IsdnBearerEntry  
SEQUENCE    
  isdnBearerChannelType INTEGER
  isdnBearerOperStatus INTEGER
  isdnBearerChannelNumber INTEGER
  isdnBearerPeerAddress DisplayString
  isdnBearerPeerSubAddress DisplayString
  isdnBearerCallOrigin INTEGER
  isdnBearerInfoType INTEGER
  isdnBearerMultirate TruthValue
  isdnBearerCallSetupTime TimeStamp
  isdnBearerCallConnectTime TimeStamp
  isdnBearerChargedUnits Gauge32

IsdnSignalingEntry  
SEQUENCE    
  isdnSignalingIndex INTEGER
  isdnSignalingIfIndex InterfaceIndex
  isdnSignalingProtocol IsdnSignalingProtocol
  isdnSignalingCallingAddress DisplayString
  isdnSignalingSubAddress DisplayString
  isdnSignalingBchannelCount Integer32
  isdnSignalingInfoTrapEnable INTEGER
  isdnSignalingStatus RowStatus

IsdnSignalingStatsEntry  
SEQUENCE    
  isdnSigStatsInCalls Counter32
  isdnSigStatsInConnected Counter32
  isdnSigStatsOutCalls Counter32
  isdnSigStatsOutConnected Counter32
  isdnSigStatsChargedUnits Counter32

IsdnLapdEntry  
SEQUENCE    
  isdnLapdPrimaryChannel TruthValue
  isdnLapdOperStatus INTEGER
  isdnLapdPeerSabme Counter32
  isdnLapdRecvdFrmr Counter32

IsdnEndpointEntry  
SEQUENCE    
  isdnEndpointIndex INTEGER
  isdnEndpointIfIndex InterfaceIndex
  isdnEndpointIfType IANAifType
  isdnEndpointTeiType INTEGER
  isdnEndpointTeiValue INTEGER
  isdnEndpointSpid DisplayString
  isdnEndpointStatus RowStatus

IsdnDirectoryEntry  
SEQUENCE    
  isdnDirectoryIndex INTEGER
  isdnDirectoryNumber DisplayString
  isdnDirectorySigIndex INTEGER
  isdnDirectoryStatus RowStatus

Defined Values

isdnMib 1.3.6.1.2.1.10.20
The MIB module to describe the management of ISDN interfaces.
MODULE-IDENTITY    

isdnMibObjects 1.3.6.1.2.1.10.20.1
OBJECT IDENTIFIER    

isdnBasicRateGroup 1.3.6.1.2.1.10.20.1.1
OBJECT IDENTIFIER    

isdnBasicRateTable 1.3.6.1.2.1.10.20.1.1.1
Table containing configuration and operational parameters for all physical Basic Rate interfaces on this managed device.
OBJECT-TYPE    
  SEQUENCE OF  
    IsdnBasicRateEntry

isdnBasicRateEntry 1.3.6.1.2.1.10.20.1.1.1.1
An entry in the ISDN Basic Rate Table.
OBJECT-TYPE    
  IsdnBasicRateEntry  

isdnBasicRateIfType 1.3.6.1.2.1.10.20.1.1.1.1.1
The physical interface type. For 'S/T' interfaces, also called 'Four-wire Basic Access Interface', the value of this object is isdns(75). For 'U' interfaces, also called 'Two-wire Basic Access Interface', the value of this object is isdnu(76).
OBJECT-TYPE    
  INTEGER isdns(75), isdnu(76)  

isdnBasicRateLineTopology 1.3.6.1.2.1.10.20.1.1.1.1.2
The line topology to be used for this interface. Note that setting isdnBasicRateIfType to isdns(75) does not necessarily mean a line topology of point-to-multipoint.
OBJECT-TYPE    
  INTEGER pointToPoint(1), pointToMultipoint(2)  

isdnBasicRateIfMode 1.3.6.1.2.1.10.20.1.1.1.1.3
The physical interface mode. For TE mode, the value of this object is te(1). For NT mode, the value of this object is nt(2).
OBJECT-TYPE    
  INTEGER te(1), nt(2)  

isdnBasicRateSignalMode 1.3.6.1.2.1.10.20.1.1.1.1.4
The signaling channel operational mode for this interface. If active(1) there is a signaling channel on this interface. If inactive(2) a signaling channel is not available.
OBJECT-TYPE    
  INTEGER active(1), inactive(2)  

isdnBearerGroup 1.3.6.1.2.1.10.20.1.2
OBJECT IDENTIFIER    

isdnBearerTable 1.3.6.1.2.1.10.20.1.2.1
This table defines port specific operational, statistics and active call data for ISDN B channels. Each entry in this table describes one B (bearer) channel.
OBJECT-TYPE    
  SEQUENCE OF  
    IsdnBearerEntry

isdnBearerEntry 1.3.6.1.2.1.10.20.1.2.1.1
Operational and statistics information relating to one port. A port is a single B channel.
OBJECT-TYPE    
  IsdnBearerEntry  

isdnBearerChannelType 1.3.6.1.2.1.10.20.1.2.1.1.1
The B channel type. If the B channel is connected to a dialup line, this object has a value of dialup(1). In this case, it is controlled by an associated signaling channel. If the B channel is connected to a leased line, this object has a value of leased(2). For leased line B channels, there is no signaling channel control available.
OBJECT-TYPE    
  INTEGER dialup(1), leased(2)  

isdnBearerOperStatus 1.3.6.1.2.1.10.20.1.2.1.1.2
The current call control state for this port. idle(1): The B channel is idle. No call or call attempt is going on. connecting(2): A connection attempt (outgoing call) is being made on this interface. connected(3): An incoming call is in the process of validation. active(4): A call is active on this interface.
OBJECT-TYPE    
  INTEGER idle(1), connecting(2), connected(3), active(4)  

isdnBearerChannelNumber 1.3.6.1.2.1.10.20.1.2.1.1.3
The identifier being used by a signaling protocol to identify this B channel, also referred to as B channel number. If the Agent also supports the DS0 MIB, the values of isdnBearerChannelNumber and dsx0Ds0Number must be identical for a given B channel.
OBJECT-TYPE    
  INTEGER 1..30  

isdnBearerPeerAddress 1.3.6.1.2.1.10.20.1.2.1.1.4
The ISDN address the current or last call is or was connected to. In some cases, the format of this information can not be predicted, since it largely depends on the type of switch or PBX the device is connected to. Therefore, the detailed format of this information is not specified and is implementation dependent. If possible, the agent should supply this information using the E.164 format. In this case, the number must start with '+'. Otherwise, IA5 number digits must be used. If the peer ISDN address is not available, this object has a length of zero.
OBJECT-TYPE    
  DisplayString  

isdnBearerPeerSubAddress 1.3.6.1.2.1.10.20.1.2.1.1.5
The ISDN subaddress the current or last call is or was connected to. The subaddress is an user supplied string of up to 20 IA5 characters and is transmitted transparently through the network. If the peer subaddress is not available, this object has a length of zero.
OBJECT-TYPE    
  DisplayString  

isdnBearerCallOrigin 1.3.6.1.2.1.10.20.1.2.1.1.6
The call origin for the current or last call. If since system startup there was no call on this interface, this object has a value of unknown(1).
OBJECT-TYPE    
  INTEGER unknown(1), originate(2), answer(3), callback(4)  

isdnBearerInfoType 1.3.6.1.2.1.10.20.1.2.1.1.7
The Information Transfer Capability for the current or last call. speech(2) refers to a non-data connection, whereas audio31(6) and audio7(7) refer to data mode connections. Note that Q.931, chapter 4.5.5, originally defined audio7(7) as '7 kHz audio' and now defines it as 'Unrestricted digital information with tones/ announcements'. If since system startup there has been no call on this interface, this object has a value of unknown(1).
OBJECT-TYPE    
  INTEGER unknown(1), speech(2), unrestrictedDigital(3), unrestrictedDigital56(4), restrictedDigital(5), audio31(6), audio7(7), video(8), packetSwitched(9)  

isdnBearerMultirate 1.3.6.1.2.1.10.20.1.2.1.1.8
This flag indicates if the current or last call used multirate. The actual information transfer rate, in detail specified in octet 4.1 (rate multiplier), is the sum of all B channel ifSpeed values for the hyperchannel. If since system startup there was no call on this interface, this object has a value of false(2).
OBJECT-TYPE    
  TruthValue  

isdnBearerCallSetupTime 1.3.6.1.2.1.10.20.1.2.1.1.9
The value of sysUpTime when the ISDN setup message for the current or last call was sent or received. If since system startup there has been no call on this interface, this object has a value of zero.
OBJECT-TYPE    
  TimeStamp  

isdnBearerCallConnectTime 1.3.6.1.2.1.10.20.1.2.1.1.10
The value of sysUpTime when the ISDN connect message for the current or last call was sent or received. If since system startup there has been no call on this interface, this object has a value of zero.
OBJECT-TYPE    
  TimeStamp  

isdnBearerChargedUnits 1.3.6.1.2.1.10.20.1.2.1.1.11
The number of charged units for the current or last connection. For incoming calls or if charging information is not supplied by the switch, the value of this object is zero.
OBJECT-TYPE    
  Gauge32  

isdnSignalingGroup 1.3.6.1.2.1.10.20.1.3
OBJECT IDENTIFIER    

isdnSignalingGetIndex 1.3.6.1.2.1.10.20.1.3.1
The recommended procedure for selecting a new index for isdnSignalingTable row creation is to GET the value of this object, and then to SET the object with the same value. If the SET operation succeeds, the manager can use this value as an index to create a new row in this table.
OBJECT-TYPE    
  TestAndIncr  

isdnSignalingTable 1.3.6.1.2.1.10.20.1.3.2
ISDN signaling table containing configuration and operational parameters for all ISDN signaling channels on this managed device.
OBJECT-TYPE    
  SEQUENCE OF  
    IsdnSignalingEntry

isdnSignalingEntry 1.3.6.1.2.1.10.20.1.3.2.1
An entry in the ISDN Signaling Table. To create a new entry, only isdnSignalingProtocol needs to be specified before isdnSignalingStatus can become active(1).
OBJECT-TYPE    
  IsdnSignalingEntry  

isdnSignalingIndex 1.3.6.1.2.1.10.20.1.3.2.1.1
The index value which uniquely identifies an entry in the isdnSignalingTable.
OBJECT-TYPE    
  INTEGER 1..2147483647  

isdnSignalingIfIndex 1.3.6.1.2.1.10.20.1.3.2.1.2
The ifIndex value of the interface associated with this signaling channel.
OBJECT-TYPE    
  InterfaceIndex  

isdnSignalingProtocol 1.3.6.1.2.1.10.20.1.3.2.1.3
The particular protocol type supported by the switch providing access to the ISDN network to which this signaling channel is connected.
OBJECT-TYPE    
  IsdnSignalingProtocol  

isdnSignalingCallingAddress 1.3.6.1.2.1.10.20.1.3.2.1.4
The ISDN Address to be assigned to this signaling channel. More specifically, this is the 'Calling Address information element' as being passed to the switch in outgoing call setup messages. It can be an EAZ (1TR6), a calling number (DSS1, ETSI) or any other number necessary to identify a signaling interface. If there is no such number defined or required, this is a zero length string. It is represented in DisplayString form. Incoming calls can also be identified by this number. If the Directory Number, i.e. the Called Number in incoming calls, is different to this number, the isdnDirectoryTable has to be used to specify all possible Directory Numbers. The format of this information largely depends on the type of switch or PBX the device is connected to. Therefore, the detailed format of this information is not specified and is implementation dependent. If possible, the agent should implement this information using the E.164 number format. In this case, the number must start with '+'. Otherwise, IA5 number digits must be used.
OBJECT-TYPE    
  DisplayString  

isdnSignalingSubAddress 1.3.6.1.2.1.10.20.1.3.2.1.5
Supplementary information to the ISDN address assigned to this signaling channel. Usually, this is the subaddress as defined in Q.931. If there is no such number defined or required, this is a zero length string. The subaddress is used for incoming calls as well as for outgoing calls. The subaddress is an user supplied string of up to 20 IA5 characters and is transmitted transparently through the network.
OBJECT-TYPE    
  DisplayString  

isdnSignalingBchannelCount 1.3.6.1.2.1.10.20.1.3.2.1.6
The total number of B channels (bearer channels) managed by this signaling channel. The default value of this object depends on the physical interface type and is either 2 for Basic Rate interfaces or 24 (30) for Primary Rate interfaces.
OBJECT-TYPE    
  Integer32 1..65535  

isdnSignalingInfoTrapEnable 1.3.6.1.2.1.10.20.1.3.2.1.7
Indicates whether isdnMibCallInformation traps should be generated for calls on this signaling channel.
OBJECT-TYPE    
  INTEGER enabled(1), disabled(2)  

isdnSignalingStatus 1.3.6.1.2.1.10.20.1.3.2.1.8
This object is used to create and delete rows in the isdnSignalingTable.
OBJECT-TYPE    
  RowStatus  

isdnSignalingStatsTable 1.3.6.1.2.1.10.20.1.3.3
ISDN signaling table containing statistics information for all ISDN signaling channels on this managed device. Only statistical information which is not already being counted in the ifTable is being defined in this table.
OBJECT-TYPE    
  SEQUENCE OF  
    IsdnSignalingStatsEntry

isdnSignalingStatsEntry 1.3.6.1.2.1.10.20.1.3.3.1
An entry in the ISDN Signaling statistics Table.
OBJECT-TYPE    
  IsdnSignalingStatsEntry  

isdnSigStatsInCalls 1.3.6.1.2.1.10.20.1.3.3.1.1
The number of incoming calls on this interface.
OBJECT-TYPE    
  Counter32  

isdnSigStatsInConnected 1.3.6.1.2.1.10.20.1.3.3.1.2
The number of incoming calls on this interface which were actually connected.
OBJECT-TYPE    
  Counter32  

isdnSigStatsOutCalls 1.3.6.1.2.1.10.20.1.3.3.1.3
The number of outgoing calls on this interface.
OBJECT-TYPE    
  Counter32  

isdnSigStatsOutConnected 1.3.6.1.2.1.10.20.1.3.3.1.4
The number of outgoing calls on this interface which were actually connected.
OBJECT-TYPE    
  Counter32  

isdnSigStatsChargedUnits 1.3.6.1.2.1.10.20.1.3.3.1.5
The number of charging units on this interface since system startup. Only the charging units applying to the local interface, i.e. for originated calls or for calls with 'Reverse charging' being active, are counted here.
OBJECT-TYPE    
  Counter32  

isdnLapdTable 1.3.6.1.2.1.10.20.1.3.4
Table containing configuration and statistics information for all LAPD (D channel Data Link) interfaces on this managed device. Only statistical information which is not already being counted in the ifTable is being defined in this table.
OBJECT-TYPE    
  SEQUENCE OF  
    IsdnLapdEntry

isdnLapdEntry 1.3.6.1.2.1.10.20.1.3.4.1
An entry in the LAPD Table.
OBJECT-TYPE    
  IsdnLapdEntry  

isdnLapdPrimaryChannel 1.3.6.1.2.1.10.20.1.3.4.1.1
If set to true(1), this D channel is the designated primary D channel if D channel backup is active. There must be exactly one primary D channel configured. If D channel backup is not used, this object has a value of true(1).
OBJECT-TYPE    
  TruthValue  

isdnLapdOperStatus 1.3.6.1.2.1.10.20.1.3.4.1.2
The operational status of this interface: inactive all layers are inactive l1Active layer 1 is activated, layer 2 datalink not established l2Active layer 1 is activated, layer 2 datalink established.
OBJECT-TYPE    
  INTEGER inactive(1), l1Active(2), l2Active(3)  

isdnLapdPeerSabme 1.3.6.1.2.1.10.20.1.3.4.1.3
The number of peer SABME frames received on this interface. This is the number of peer-initiated new connections on this interface.
OBJECT-TYPE    
  Counter32  

isdnLapdRecvdFrmr 1.3.6.1.2.1.10.20.1.3.4.1.4
The number of LAPD FRMR response frames received. This is the number of framing errors on this interface.
OBJECT-TYPE    
  Counter32  

isdnEndpointGroup 1.3.6.1.2.1.10.20.1.4
OBJECT IDENTIFIER    

isdnEndpointGetIndex 1.3.6.1.2.1.10.20.1.4.1
The recommended procedure for selecting a new index for isdnEndpointTable row creation is to GET the value of this object, and then to SET the object with the same value. If the SET operation succeeds, the manager can use this value as an index to create a new row in this table.
OBJECT-TYPE    
  TestAndIncr  

isdnEndpointTable 1.3.6.1.2.1.10.20.1.4.2
Table containing configuration for Terminal Endpoints.
OBJECT-TYPE    
  SEQUENCE OF  
    IsdnEndpointEntry

isdnEndpointEntry 1.3.6.1.2.1.10.20.1.4.2.1
An entry in the Terminal Endpoint Table. The value of isdnEndpointIfType must be supplied for a row in this table to become active.
OBJECT-TYPE    
  IsdnEndpointEntry  

isdnEndpointIndex 1.3.6.1.2.1.10.20.1.4.2.1.1
The index value which uniquely identifies an entry in the isdnEndpointTable.
OBJECT-TYPE    
  INTEGER 1..2147483647  

isdnEndpointIfIndex 1.3.6.1.2.1.10.20.1.4.2.1.2
The ifIndex value of the interface associated with this Terminal Endpoint.
OBJECT-TYPE    
  InterfaceIndex  

isdnEndpointIfType 1.3.6.1.2.1.10.20.1.4.2.1.3
The interface type for this Terminal Endpoint. Interface types of x25ple(40) and isdn(63) are allowed. The interface type is identical to the value of ifType in the associated ifEntry.
OBJECT-TYPE    
  IANAifType  

isdnEndpointTeiType 1.3.6.1.2.1.10.20.1.4.2.1.4
The type of TEI (Terminal Endpoint Identifier) used for this Terminal Endpoint. In case of dynamic(1), the TEI value is selected by the switch. In case of static(2), a valid TEI value has to be entered in the isdnEndpointTeiValue object. The default value for this object depends on the interface type as well as the Terminal Endpoint type. On Primary Rate interfaces the default value is static(2). On Basic Rate interfaces the default value is dynamic(1) for isdn(63) Terminal Endpoints and static(2) for x25ple(40) Terminal Endpoints.
OBJECT-TYPE    
  INTEGER dynamic(1), static(2)  

isdnEndpointTeiValue 1.3.6.1.2.1.10.20.1.4.2.1.5
The TEI (Terminal Endpoint Identifier) value for this Terminal Endpoint. If isdnEndpointTeiType is set to static(2), valid numbers are 0..63, while otherwise the value is set internally. The default value of this object is 0 for static TEI assignment. The default value for dynamic TEI assignment is also 0 as long as no TEI has been assigned. After TEI assignment, the assigned TEI value is returned.
OBJECT-TYPE    
  INTEGER 0..255  

isdnEndpointSpid 1.3.6.1.2.1.10.20.1.4.2.1.6
The Service profile IDentifier (SPID) information for this Terminal Endpoint. The SPID is composed of 9-20 numeric characters. This information has to be defined in addition to the local number for some switch protocol types, e.g. Bellcore NI-1 and NI-2. If this object is not required, it is a zero length string.
OBJECT-TYPE    
  DisplayString  

isdnEndpointStatus 1.3.6.1.2.1.10.20.1.4.2.1.7
This object is used to create and delete rows in the isdnEndpointTable.
OBJECT-TYPE    
  RowStatus  

isdnDirectoryGroup 1.3.6.1.2.1.10.20.1.5
OBJECT IDENTIFIER    

isdnDirectoryTable 1.3.6.1.2.1.10.20.1.5.1
Table containing Directory Numbers.
OBJECT-TYPE    
  SEQUENCE OF  
    IsdnDirectoryEntry

isdnDirectoryEntry 1.3.6.1.2.1.10.20.1.5.1.1
An entry in the Directory Number Table. All objects in an entry must be set for a new row to become active.
OBJECT-TYPE    
  IsdnDirectoryEntry  

isdnDirectoryIndex 1.3.6.1.2.1.10.20.1.5.1.1.1
The index value which uniquely identifies an entry in the isdnDirectoryTable.
OBJECT-TYPE    
  INTEGER 1..7fffffff  

isdnDirectoryNumber 1.3.6.1.2.1.10.20.1.5.1.1.2
A Directory Number. Directory Numbers are used to identify incoming calls on the signaling channel given in isdnDirectorySigIndex. The format of this information largely depends on the type of switch or PBX the device is connected to. Therefore, the detailed format of this information is not specified and is implementation dependent. If possible, the agent should implement this information using the E.164 number format. In this case, the number must start with '+'. Otherwise, IA5 number digits must be used.
OBJECT-TYPE    
  DisplayString  

isdnDirectorySigIndex 1.3.6.1.2.1.10.20.1.5.1.1.3
An index pointing to an ISDN signaling channel. Incoming calls are accepted on this signaling channel if the isdnDirectoryNumber is presented as Called Number in the SETUP message.
OBJECT-TYPE    
  INTEGER 1..2147483647  

isdnDirectoryStatus 1.3.6.1.2.1.10.20.1.5.1.1.4
This object is used to create and delete rows in the isdnDirectoryTable.
OBJECT-TYPE    
  RowStatus  

isdnMibTrapPrefix 1.3.6.1.2.1.10.20.2
OBJECT IDENTIFIER    

isdnMibTraps 1.3.6.1.2.1.10.20.2.0
OBJECT IDENTIFIER    

isdnMibCallInformation 1.3.6.1.2.1.10.20.2.0.1
This trap/inform is sent to the manager under the following condidions: - on incoming calls for each call which is rejected for policy reasons (e.g. unknown neighbor or access violation) - on outgoing calls whenever a call attempt is determined to have ultimately failed. In the event that call retry is active, then this will be after all retry attempts have failed. - whenever a call connects. In this case, the object isdnBearerCallConnectTime should be included in the trap. Only one such trap is sent in between successful or unsuccessful call attempts from or to a single neighbor; subsequent call attempts result in no trap. If the Dial Control MIB objects dialCtlNbrCfgId and dialCtlNbrCfgIndex are known by the entity generating this trap, both objects should be included in the trap as well. The receipt of this trap with no dial neighbor information indicates that the manager must poll the callHistoryTable of the Dial Control MIB to see what changed.
NOTIFICATION-TYPE    

isdnMibConformance 1.3.6.1.2.1.10.20.3
OBJECT IDENTIFIER    

isdnMibCompliances 1.3.6.1.2.1.10.20.3.1
OBJECT IDENTIFIER    

isdnMibGroups 1.3.6.1.2.1.10.20.3.2
OBJECT IDENTIFIER    

isdnMibCompliance 1.3.6.1.2.1.10.20.3.1.1
It is conformant to implement this object as read-only.
MODULE-COMPLIANCE    

isdnMibBasicRateGroup 1.3.6.1.2.1.10.20.3.2.1
A collection of objects required for ISDN Basic Rate physical interface configuration and statistics.
OBJECT-GROUP    

isdnMibBearerGroup 1.3.6.1.2.1.10.20.3.2.2
A collection of objects required for ISDN Bearer channel control and statistics.
OBJECT-GROUP    

isdnMibSignalingGroup 1.3.6.1.2.1.10.20.3.2.3
A collection of objects required for ISDN D channel configuration and statistics.
OBJECT-GROUP    

isdnMibEndpointGroup 1.3.6.1.2.1.10.20.3.2.4
A collection of objects describing Terminal Endpoints.
OBJECT-GROUP    

isdnMibDirectoryGroup 1.3.6.1.2.1.10.20.3.2.5
A collection of objects describing directory numbers.
OBJECT-GROUP