INTERNET-DRAFT ISDN MIB October 1995 ISDN Management Information Base draft-ietf-isdnmib-snmp-isdn-mib-01.txt Fri Oct 6 11:53:57 MET 1995 Guenter Roeck Conware GmbH roeck@conware.de Status of this Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its Areas, and its Working Groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as a "work in progress". To learn the current status of any Internet-Draft, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Expires April 1996 [Page 1] INTERNET-DRAFT ISDN MIB October 1995 1. Introduction This draft defines an experimental portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it defines a minimal set of managed objects for SNMP-based management of ISDN interfaces. ISDN interfaces are supported on a variety of equipment (for data and voice) including terminal adapters, bridges, hosts, and routers. The set of objects will be consistent with the SNMP framework and existing SNMP standards. This document is a product of the ISDN MIB working group within the Internet Engineering Task Force. Comments are solicited and should be addressed to the working group's mailing list at isdn-mib@combinet.com and/or the author. Expires April 1996 [Page 2] INTERNET-DRAFT ISDN MIB October 1995 2. The SNMPv2 Network Management Framework The SNMPv2 Network Management Framework consists of four major components. They are: o RFC 1442 [1] which defines the SMI, the mechanisms used for describing and naming objects for the purpose of management. o STD 17, RFC 1213 [2] defines MIB-II, the core set of managed objects for the Internet suite of protocols. o RFC 1445 [3] which defines the administrative and other architectural aspects of the framework. o RFC 1448 [4] which defines the protocol used for network access to managed objects. The Framework permits new objects to be defined for the purpose of experimentation and evaluation. 2.1. Object Definitions Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the subset of Abstract Syntax Notation One (ASN.1) defined in the SMI. In particular, each object type is named by an OBJECT IDENTIFIER, an administratively assigned name. The object type together with an object instance serves to uniquely identify a specific instantiation of the object. For human convenience, we often use a textual string, termed the descriptor, to refer to the object type. Expires April 1996 [Page 3] INTERNET-DRAFT ISDN MIB October 1995 3. Overview 3.1. Structure of MIB For managing ISDN interfaces, the following information is necessary: o Information for managing physical interfaces. In case of ISDN primary rate, this will usually be T1 or E1 lines, being managed in the Trunk MIB. For Basic Rate lines, physical interfaces will be managed by this MIB. o Information for managing signalling channels, usually referred to as D channels. o Information for managing bearer channels, usually referred to as B channels. Within this document, this information has been structured into three groups, which will be described in the following chapters. In order to manage connections over ISDN lines, the management of neighbors and call history information is required as well. This information will be defined in the Dial Control MIB. The purpose for splitting the required information in two MIBs is to be able to use parts of this information for non-ISDN interfaces as well. In particular, the Dial Control MIB might also be used for other types of interfaces. 3.1.1. General Description This MIB controls signalling channels as well as B channels and physical Basic Rate interfaces. It consists of three groups. o The isdnMibBasicRateGroup is used to provide information regarding physical Basic Rate interfaces. o The isdnMibSignallingGroup is used to control ISDN signalling channels. It consists of two tables, the isdnSignallingTable for configuration information and the isdnSignallingStatsTable for statistics information. o The isdnBearerGroup is used to control bearer channels, usually referred to as B channels. It supports configuration parameters as Expires April 1996 [Page 4] INTERNET-DRAFT ISDN MIB October 1995 well as statistical information related to B channels. 3.2. Relationship to RFC 1573 RFC 1573, the Interface MIB Evolution, requires that any MIB module which is an adjunct of the Interface MIB, clarify specific areas within the Interface MIB. These areas were intentionally left vague in RFC 1573 to avoid over constraining the MIB module, thereby precluding management of certain media-types. Section 3.3 of RFC 1573 enumerates several areas which a media-specific MIB module must clarify. Each of these areas is addressed in a following subsection. The implementor is referred to RFC 1573 in order to understand the general intent of these areas. 3.2.1. Layering Model An ISDN interface usually consists of a signalling channel (D channel) and a number of bearer channels (B channels), all of which will be layered on top of a physical interface. This is accomplished in this MIB by creating a logical interface (ifEntry) for each of the D channels and a logical interface (ifEntry) for each of the B channels. These are then correlated to each other and to the physical interface using the ifStack table of RFC 1573. Expires April 1996 [Page 5] INTERNET-DRAFT ISDN MIB October 1995 The basic model, therefore, looks something like this: | | | | | | <== interface to upper +--+ +--+ +--+ +--+ +--+ +--+ layers, to be handled | D | | B | | B | by Dial Control MIB |channel| |channel| .... |channel| and ifStack table +--+ +--+ +--+ +--+ +--+ +--+ | | | | | | <== attachment to physical +--+ +--------+ +------------+ +----+ interfaces, to be provided | physical interface | by ifStack table | (S0/Uk0 or T1/E1) | +-----------------------------------+ Mapping of B/D channels to physical interfaces IfEntries are maintained for D channels and for each B channel. The D channel's interface ifType is one of the ISDN interface types; the B channel ifType is isdn(63). The ifType for physical interfaces is the matching IANA ifType, usually T1 or E1 for physical Primary Rate interfaces and >>to be assigned<< for physical Basic Rate interfaces. The ifStackTable is used to map B and D channels to physical interfaces. Conceivably, X.25 or Frame Relay interface MIBs could then be layered on the D channel. Mapping of B channels to upper interface layers will usually be done using the Dial Control MIB. For example, mapping on top of B channels might look as follows: Expires April 1996 [Page 6] INTERNET-DRAFT ISDN MIB October 1995 +-------------------------------------------------------+ | Network Layer Protocol | +------+ +-------+ +-------+ +-------+ +-------+ +------+ | | | | | | | | | | <== appears active +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ | PPP | | PPP | | F/R | | PPP | | F/R | | for | | for | | for | | for | | for | ifEntry with |Nbr 1| |Nbr 2| |switch |Nbr 3| |switch shadow | | | | | A | | | | B | NeighborEntry +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ | | | | <== some actually are +--+ +--+ +--+ +--+ +--+ +--+ +--+ +--+ +--+ +--+ | B | | B | | B | | B | | B | |channel| |channel| |channel| |channel| |channel| +--+ +--+ +--+ +--+ +--+ +--+ +--+ +--+ +--+ +--+ | | | | | | | | | | +------+ +-------+ +-------+ +-------+ +-------+ +------+ | Basic/Primary Rate Interface | +-------------------------------------------------------+ Mapping of IP interfaces to Called Neighbors to B Channels In this model, ifEntries are maintained for each neighbor. Each neighbor is required to have an associated ifEntry. This interface can be of any kind, e.g. PPP or LAPB. 3.2.2. ifTestTable The ifTestTable is not supported by this MIB. 3.2.3. ifRcvAddressTable The ifRcvAddressTable is not supported by this MIB. Expires April 1996 [Page 7] INTERNET-DRAFT ISDN MIB October 1995 3.2.4. ifEntry 3.2.4.1. ifEntry for a Basic Rate hardware interface The ifGeneralGroup of RFC 1573 is being supported for Basic Rate hardware interfaces. ifTable Comments ============== =========================================== ifIndex Each ISDN Basic Rate hardware interface is represented by an ifEntry. ifDescr Textual port description. ifType An IANA value to be assigned. ifSpeed The overall bandwidth of this interface. ifPhysAddress Return zero. ifAdminStatus The desired administrative status of the ISDN interface. ifOperStatus The current operational status of this interface. If the operational status is dormant(5), the interface is in standby mode, i.e. connnected to the network, but without call activity. If the operational status is down(2), the hardware has detected that there is no level 1 connection to the switch. ifLastChange Refer to RFC 1573. ifLinkUpDownTrapEnable Refer to RFC 1573. ifConnectorPresent Refer to RFC 1573. ifHighSpeed Return zero. ifName Refer to RFC 1573. Expires April 1996 [Page 8] INTERNET-DRAFT ISDN MIB October 1995 3.2.4.2. ifEntry for a D channel (signalling channel) The ifEntry for a D channel supports the ifGeneralGroup and the ifPacketGroup of RFC 1573. ifTable Comments ============== =========================================== ifIndex Each ISDN D channel is represented by an ifEntry. ifDescr Textual port description. ifType The IANA value of basicISDN(20) or primaryISDN(21), depending on the media type. ifSpeed The bandwidth of this D channel. Usually, this will be the value of 16000 for basic rate interfaces or 64000 for primary rate interfaces. ifPhysAddress The ISDN address assigned to this signalling interface. This is a copy of isdnSigTblCalledAddress. ifAdminStatus The desired administrative status of the ISDN interface. ifOperStatus The current operational status of the ISDN UNI (User Network Interface) interface. If the operational status is dormant(5), the D channel is in standby mode (see [5], Annex F, D channel backup procedures). ifLastChange Refer to RFC 1573. ifLinkUpDownTrapEnable Refer to RFC 1573. ifConnectorPresent Refer to RFC 1573. ifHighSpeed Return zero. ifName Refer to RFC 1573. ifMtu The size of the largest frame which can be sent/received on this D Channel, specified in octets. Expires April 1996 [Page 9] INTERNET-DRAFT ISDN MIB October 1995 ifInOctets The total number of octets received on this D channel. ifInUcastPkts The number of frames received on this D channel whose address is not TEI=127. ifInNUcastPkts Deprecated. Return the number of frames received on this D channel which is targeted TEI=127. ifInDiscards The total number of received frames which have been discarded. The possible reasons are: buffer shortage. ifInErrors The number of inbound frames that contained errors preventing them from being deliverable to LAPD. ifInUnknownProtos The number of frames with this interface's TEI, but unknown SAPI. ifOutOctets The total number of octets transmitted on this D channel. ifOutUcastPkts The number of frames transmitted on this D channel whose address is not TEI=127. ifOutNUcastPkts Deprecated. Return the number of frames transmitted on this D channel which have TEI=127. ifOutDiscards The total number of outbound frames which were discarded. Possible reasons are: buffer shortage. ifOutErrors The number of frames which could not be transmitted due to errors. ifOutQlen Deprecated. Return zero. ifSpecific Deprecated. Return {0 0}. Expires April 1996 [Page 10] INTERNET-DRAFT ISDN MIB October 1995 3.2.4.3. ifEntry for a B channel (bearer channel) The ifEntry for a B channel supports the ifGeneralGroup and the ifPacketGroup of RFC 1573. ifTable Comments ============== =========================================== ifIndex Each ISDN B channel is represented by an ifEntry. ifDescr Textual port description. ifType The IANA value of isdn(63). ifSpeed The bandwidth of this B channel. Usually, this will be the value of 56000 or 64000. For ISDN leased lines (or eventually hyperchannels), this will be the total capacity of this interface. ifPhysAddress The ISDN address assigned to this port. This is a copy of isdnBearerCalledAddress. ifAdminStatus The desired administrative status of the ISDN port. ifOperStatus The current operational status of the ISDN port. Note that dormant(5) is explicitely being used as defined in RFC 1573. ifLastChange Refer to RFC 1573. ifLinkUpDownTrapEnable Refer to RFC 1573. ifConnectorPresent Refer to RFC 1573. ifHighSpeed Return zero. ifName Refer to RFC 1573. ifMtu The size of the largest frame which can be sent/received on this B Channel, specified in octets. Expires April 1996 [Page 11] INTERNET-DRAFT ISDN MIB October 1995 ifInOctets The total number of octets received on this B channel. ifInUcastPkts The number of frames received on this B channel. ifInNUcastPkts Deprecated. Return zero. ifInDiscards The total number of received frames discards. The possible reasons are: buffer shortage. ifInErrors The number of inbound frames that contained errors preventing them from being deliverable to a higher-layer protocol. ifInUnknownProtos The number of inbound frames with unknown upper layers. ifOutOctets The total number of octets transmitted on this B channel. ifOutUcastPkts The number of frames transmitted on this B channel. ifOutNUcastPkts Deprecated. Return zero. ifOutDiscards The total number of outbound frames which were discarded. Possible reasons are: buffer shortage. ifOutErrors The number of frames which could not be transmitted due to errors. ifOutQlen Deprecated. Return zero. ifSpecific Deprecated. Return {0 0}. Expires April 1996 [Page 12] INTERNET-DRAFT ISDN MIB October 1995 3.3. ISDN interface specific information 3.3.1. ISDN leased lines ISDN leased lines on Basic Rate interfaces can be specified by setting the value of isdnBasicTblConnectionType to one of the leased line types. There will be no signalling table entry for leased lines, since there is no signalling channel available. Thus, only B channel interfaces will exist in this case. For Primary Rate interfaces, a leased line does not have any ISDN specifics. Therefore, Primary Rate leased lines will entirely be handled by the according MIB for this kind of interfaces, i.e. the Trunk MIB for E1/T1 interfaces. No ISDN ifEntries will exist in this case. 3.3.2. Hyperchannels The switch protocol in use will define if hyperchannels are being supported, and the actual support will be implementation dependent. Hyperchannel connections itself will be requested by the interface user, e.g. by the neighbor connection handling procedures. In the ISDN MIB, the isdnBearerStatsMultirate object of isdnBearerStatsTable can be used to check if hyperchannels are being used for an active call. 3.3.3. D channel backup and NFAS trunks D channel backup is defined in [5], Annex F. It describes non- associated signalling and its use and functionality is basically identical to NFAS trunks. Non Facility Accociated Signalling (NFAS) basically means that a D channel on a PRI interface is used to manage calls on other PRI trunks. This is required in North America for H11 channels, since all 24 time slots are being used for bearer channels. According to [5], Annex F, the D channel backup feature can be provided on a subscription basis and is network dependent. The D channel backup procedure is described in detail in [5]. In case of D channel backup or NFAS trunks, the isdnSigTblPhysInterface object defines the physical interface the D channel resides on. Using Expires April 1996 [Page 13] INTERNET-DRAFT ISDN MIB October 1995 the ifStack table, the active D channel is layered on top of all physical interfaces being managed by this D channel. In case of D channel backup, inactive D channels will have an operational status of dormant(5). 3.3.4. X.25 data transfer in D channel Transfer of X.25 data over D channels can be handled by attaching an X.25 interface to a D channel using the ifStack table of RFC 1573. 3.3.5. SPID handling Service Profile IDentifiers (SPID) are defined for BRI interfaces only, and being used in North America. SPIDs are required for DMS-100 and NI- 1, and are optional for 5ESS. A switch can define up to 8 SPIDs per BRI. Usually, each B channel has one SPID assigned. It is normally built from the party number (calling address for outgoing calls) with a number of digits prepended and appended. Since each network appears to be different, both the calling address and the SPID have to be stored. The SPID identifies the particular services that have been provisioned for a terminal. If there are two B channels on a BRI, there can be two SPIDs, one for each of the two B channels. The SPID gets registered with the switch after link establishment. There is one data link for each SPID. As part of terminal registration, an EID (Endpoint IDentifier) is defined by the switch. On incoming calls, the switch may provide the EID, a called party number, or both, depending on the ISDN code implemented in the switch. The EID has two bytes: USID (User Service IDentifier) and TID (Terminal IDentifier). These are later used by some of the software versions running on the switch side (e.g. compliant with NI-1, 5ESS custom) to broadcast SETUP messages with these included, so the correct endpoint would accept the call. Other switch software versions identify the endpoint with the Called Party Number. In the ISDN MIB, the SPID can be entered using the isdnBearerIfSpid object of isdnBearerTable. The isdnBearerCallingAddress, already being used to specify the calling number, cannot be used for this purpose, since both may differ and be required in parallel. Expires April 1996 [Page 14] INTERNET-DRAFT ISDN MIB October 1995 3.3.6. Closed User Groups Closed User Groups (CUG), as defined in [5], chapter 4.6.1, are being supported for circuit mode calls at least by ETSI and 1TR6. In this networks, an ISDN address can have one or more CUG numbers assigned. To such addresses, only calls from attached Closed User Groups will be accepted by the network. Thus, Closed User Groups are a parameter for neighbor entries and will thus be defined in the Dial Control MIB. A neighbor entry attached to a Closed User Group will have to point to an ISDN interface which belongs to the Closed User group in question. 3.3.7. Provision of point-to-point line topology In the ISDN standards, there are two different meanings for the term "point-to-point". In ISDN standards, the term point-to-point will usually be used for data link connections, i.e. layer 2 connections, where each layer 2 connection from the TE to the network is a single point-to-point connection. Multiple connections of this kind may exist on one physical (layer 1) connection, however, and in case of Basic Rate interfaces there may be several TE's connected to one physical line to the network. The second meaning of "point-to-point" refers to the line topology, i.e. to layer 1 connections. For Primary Rate interfaces, the layer 1 connection will always be of the point-to-point type. For Basic Rate interfaces, layer 1 point-to-point connections do exist in several countries, usually being used for connecting PBX systems to the network. The second meaning (layer 1 connections) is what will be referred to as "point-to-point" connection throughout this document. The isdnSignallingTable object isdnSigTblLineTopology can be used to select the line topology. In case of Primary Rate interfaces, this object will always have a value of pointToPoint(1). 3.3.8. Speech and audio bearer capability information elements The objects speech(1), audio_31() and audio_7(), as being used in isdnBearerStatsInfoType, refer to the Speech, 3.1 kHz Audio and old 7 kHz Audio (now Multi-use) bearer capabilities for ISDN, as defined in Expires April 1996 [Page 15] INTERNET-DRAFT ISDN MIB October 1995 [5], chapter 4.5.5, octet 3 of bearer capability information element. These capabilities are signaling artifices that allow networks to do certain things with the call. It is up to the network to decide what to do. The Speech Bearer Capability means that speech is being carried over the channel, as in two people talking. This would be POTS-type speech. The network may compress this, encrypt it or whatever it wants with it as long as it delivers POTS quality speech to the other end. In other words, a modem is not guaranteed to work over this connection. The 3.1 kHz Audio capability indicates that the network carries the 3.1 kHz bandwidth across the network. This would (theoretically) allow modem signals to be carried across the network. In the US, the network automatically enters a capability of 3.1 kHz Audio on calls coming into the ISDN from a POTS network. This capability restricts the network from messing with the data channel in a way that would corrupt the 3.1 kHz VoiceBand data. 7 kHz Audio was meant to signal the use of a higher quality audio connection (e.g., music from radio). It got changed to Multi-Use capability to allow it to be used for videoconferencing with fall back to audio or something like that. In some cases, the Speech or 3.1 kHz Bearer Capability provides a 56 kbit/s data path through the network. Therefore, some people are setting up calls with the Speech or 3.1 kHz BC and transmitting 56 kbit/s data over the connection. This is usually to take advantage of favorable tariffs for Speech as opposed to Data. On the incoming side, the equipment is usually configured to ignore the Bearer Capability and either answer all Speech calls as 56 kbit/s data or to use one Directory Number for real speech and another for data. Expires April 1996 [Page 16] INTERNET-DRAFT ISDN MIB October 1995 4. Definitions ISDN-MIB DEFINITIONS ::= BEGIN IMPORTS MODULE-IDENTITY, OBJECT-TYPE, Counter32, Integer32 FROM SNMPv2-SMI DisplayString, TruthValue, TimeStamp, TEXTUAL-CONVENTION FROM SNMPv2-TC MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF ifIndex, InterfaceIndex FROM IF-MIB transmission FROM RFC1213-MIB; isdnMib MODULE-IDENTITY LAST-UPDATED "9510061157Z" ORGANIZATION "IETF ISDN MIB Working Group" CONTACT-INFO " Guenter Roeck Postal: Conware GmbH Killisfeldstrasse 64 76227 Karlsruhe Germany Tel: +49 721 9495 0 E-mail: roeck@conware.de" DESCRIPTION "The MIB module to describe the management of ISDN interfaces." ::= { transmission 20 } -- The ISDN hardware interface (BRI or PRI) will be represented -- by a media specific ifEntry. -- -- For basic rate lines, the media specifics for the physical interface Expires April 1996 [Page 17] INTERNET-DRAFT ISDN MIB October 1995 -- will be defined in the physical interface group of the ISDN MIB. -- The ifType for physical basic rate interfaces will be tbd(xxx). -- -- For primary rate, the media specifics will be defined in the Trunk MIB. -- The ifType will be one of E1 or T1, depending on the line type. -- Each signalling channel, also called D channel, will be represented -- by an entry in the isdnSignallingTable. -- This will have an ifType value of basicISDN(20) -- or primaryISDN(21), refer to RFC 1213. -- Each B channel will also be represented as an entry -- in the ifTable. The B channels will have an ifType value -- of isdn(63). -- This model will be used while defining objects and tables -- for management. -- The ISDN MIB will allow sub-layers. For example, the data transfer -- over a B channel may take place with PPP encapsulation. While the -- ISDN MIB will describe the D and B channels, a media specific MIB for -- PPP can be used on a layered basis. This will be as per RFC 1573. -- Textual conventions IsdnSignallingProtocol ::= TEXTUAL-CONVENTION STATUS current DESCRIPTION "This data type is used as the syntax of the isdnSigTblSignallingProtocol object in the definition of ISDN-MIB's isdnSignallingTable. The definition of this textual convention with the addition of newly assigned values is published periodically by the IANA, in either the Assigned Numbers RFC, or some derivative of it specific to Internet Network Management number assignments. (The latest arrangements can be obtained by contacting the IANA.) Requests for new values should be made to IANA via email (iana@isi.edu)." SYNTAX INTEGER { other(1), -- none of the following dss1(2), -- ITU DSS1 (formerly CCITT) Q.931 etsi(3), -- Europe / ETSI ETS300-102 -- plus supplementary services -- (ETSI 300-xxx) Expires April 1996 [Page 18] INTERNET-DRAFT ISDN MIB October 1995 -- note that NET3, NET5 define -- test procedures for ETS300-102 -- and have been replaced by -- I-CTR 3 and I-CTR 4. btnr(4), -- U.K. / BTNR (BRI ?) (retired ?) dass2(5), -- U.K. / DASS2 (PRI) ess4(6), -- U.S.A. / AT&T 4ESS ess5(7), -- U.S.A. / AT&T 5ESS dms100(8), -- U.S.A. / Northern Telecom DMS100 dms250(9), -- U.S.A. / Northern Telecom DMS250 ni1(10), -- U.S.A. / National ISDN 1 (BRI) ni2(11), -- U.S.A. / National ISDN 2 (BRI, PRI) ni3(12), -- U.S.A. / next one ? vn2(13), -- France / VN2 vn3(14), -- France / VN3 vn4(15), -- France / VN4 (ETSI with changes) vn6(16), -- France / VN6 (ETSI with changes) -- delta document CSE P 10-21 A -- test document CSE P 10-20 A kdd(17), -- Japan / KDD ins64(18), -- Japan / NTT INS64 ins1500(19), -- Japan / NTT INS1500 itr6(20), -- Germany/ 1TR6 (BRI, PRI) cornet(21), -- Germany/ Siemens HiCom CORNET tad2(22), -- ??? / (BRI) tad30(23), -- ??? / (PRI) ts013(24), -- Australia / TS013 (formerly TPH 1962, BRI) ts014(25), -- Australia / TS014 (formerly TPH 1856, PRI) dpnss(26), -- ??? qsig(27) -- Q.SIG } -- Isdn Mib objects definitions isdnMibObjects OBJECT IDENTIFIER ::= { isdnMib 1 } -- ISDN physical interface group -- This group describes physical basic rate interfaces. -- Basic rate interfaces can either be dialup lines, -- supporting B channels as well as having an active signalling -- channel, or leased line interfaces connecting up to two B channels -- and one D channel directly to a neighbor. -- In case of leased line interfaces, there will be no signalling Expires April 1996 [Page 19] INTERNET-DRAFT ISDN MIB October 1995 -- protocol active and thus be no isdnSignallingTable entry -- layered on top of the physical interface. isdnBasicRateGroup OBJECT IDENTIFIER ::= { isdnMibObjects 1 } isdnBasicRateTable OBJECT-TYPE SYNTAX SEQUENCE OF IsdnBasicRateTableEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "Table containing configuration and operational parameters for all physical Basic Rate interfaces on this managed device." ::= { isdnBasicRateGroup 1 } isdnBasicRateTableEntry OBJECT-TYPE SYNTAX IsdnBasicRateTableEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "An entry in the ISDN Basic Rate Table." INDEX { ifIndex } ::= { isdnBasicRateTable 1 } IsdnBasicRateTableEntry ::= SEQUENCE { isdnBasicTblIfType INTEGER, isdnBasicTblConnectionType INTEGER } isdnBasicTblIfType OBJECT-TYPE SYNTAX INTEGER { isdnS0(1), isdnUk0(2) } MAX-ACCESS read-write STATUS current DESCRIPTION "The physical interface type." ::= { isdnBasicRateTableEntry 1 } isdnBasicTblConnectionType OBJECT-TYPE SYNTAX INTEGER { dialup(1), -- dialup line, with active signalling channel leased1B(2), -- leased line, 1B channel leased1B1D(3), -- leased line, 1B+D Expires April 1996 [Page 20] INTERNET-DRAFT ISDN MIB October 1995 leased2B(4), -- leased line, 2B leased2B1D(5) -- leased line, 2B+D } MAX-ACCESS read-write STATUS current DESCRIPTION "The particular connection being handled over this physical interface." ::= { isdnBasicRateTableEntry 2 } -- ISDN signalling group isdnSignallingGroup OBJECT IDENTIFIER ::= { isdnMibObjects 2 } -- Assumptions being made: -- - BRI/PRI definition will be handled in ifTable, thus not -- be required here. -- D channel configuration table -- There is one entry for each D channel (also called signalling -- channel) in this table. -- -- D channel backup and NFAS trunks will be handled using the -- ifStack table. isdnSignallingTable OBJECT-TYPE SYNTAX SEQUENCE OF IsdnSignallingTableEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "ISDN signalling table containing configuration and operational parameters for all ISDN signalling interfaces on this managed device." ::= { isdnSignallingGroup 1 } isdnSignallingTableEntry OBJECT-TYPE SYNTAX IsdnSignallingTableEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "An entry in the ISDN Signalling Table." INDEX { ifIndex } ::= { isdnSignallingTable 1 } Expires April 1996 [Page 21] INTERNET-DRAFT ISDN MIB October 1995 IsdnSignallingTableEntry ::= SEQUENCE { isdnSigTblPhysInterface InterfaceIndex, isdnSigTblSignallingProtocol IsdnSignallingProtocol, isdnSigTblLineTopology INTEGER, isdnSigTblCalledAddress DisplayString, isdnSigTblCallingAddress DisplayString, isdnSigTblSubAddress DisplayString, isdnSigTblBchannelCount Integer32, isdnSigTblOperStatus INTEGER } isdnSigTblPhysInterface OBJECT-TYPE SYNTAX InterfaceIndex MAX-ACCESS read-only STATUS current DESCRIPTION "ifIndex value of the physical interface the D channel resides on. In case of NFAS trunks, this object is required to define the physical interface the D channel resides on, since the attached ifEntry will be layered on top of all interfaces being managed by this signalling channel." ::= { isdnSignallingTableEntry 1 } -- -- Editor's note: -- We decided to have IANA supporting the signalling protocols. -- Thus, each switch manufacturer or anyone needing a new protocol -- entry will be responsible for getting a value from IANA. -- The definition has thereby been moved into a textual convention -- defined above. isdnSigTblSignallingProtocol OBJECT-TYPE SYNTAX IsdnSignallingProtocol MAX-ACCESS read-write STATUS current DESCRIPTION "The particular protocol type supported by the switch providing access to the ISDN network to which this signalling interface is connected." ::= { isdnSignallingTableEntry 2 } isdnSigTblLineTopology OBJECT-TYPE SYNTAX INTEGER { pointToPoint(1), pointToMultipoint(2) Expires April 1996 [Page 22] INTERNET-DRAFT ISDN MIB October 1995 } MAX-ACCESS read-write STATUS current DESCRIPTION "The line topology to be used for this interface. On Primary Rate interfaces, this object must have a value of pointToPoint(1) and should be read-only." ::= { isdnSignallingTableEntry 3 } isdnSigTblCalledAddress OBJECT-TYPE SYNTAX DisplayString MAX-ACCESS read-write STATUS current DESCRIPTION "This object specifies the number being passed by the switch on incoming call setup messages as 'Called Number information element'. This can be an EAZ (1TR6), a called number (DSS1, ETSI) or any other number necessary to identify a signalling interface. If there is no such number defined or required, this is a zero length string. It is represented in DisplayString form. This parameter can be specified on a per-B-channel or per-D-channel base. If specified here (e.g. on PRI interfaces), all incoming calls will have to be addressed to this number. Called numbers for incoming calls can also be defined on a per-B-channel base, thus enabling structured access to B channels. " ::= { isdnSignallingTableEntry 4 } isdnSigTblCallingAddress OBJECT-TYPE SYNTAX DisplayString MAX-ACCESS read-write STATUS current DESCRIPTION "The ISDN Address to be assigned to this signalling interface. More specific, 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 called number (DSS1, ETSI) or any other number necessary to identify a signalling interface. If there is no such number defined or required, Expires April 1996 [Page 23] INTERNET-DRAFT ISDN MIB October 1995 or if the called number on incoming calls is identical to the calling number on outgoing calls, this is a zero length string. It is represented in DisplayString form. This parameter can be specified on a per-B-channel or per-D-channel base. If specified here (e.g. on PRI interfaces), all outgoig calls will use this number as 'calling address'. Calling numbers for outgoing calls can also be defined on a per-B-channel base, thus enabling structured access to B channels. " ::= { isdnSignallingTableEntry 5 } isdnSigTblSubAddress OBJECT-TYPE SYNTAX DisplayString MAX-ACCESS read-write STATUS current DESCRIPTION "Supplementary information to the ISDN address assigned to this interface. Usually, this will be the subaddress as defined in Q.931. If there is no such number defined or required, this is a zero length string. The subaddress will be used for incoming calls as well as for outgoing calls. It is represented in DisplayString form." ::= { isdnSignallingTableEntry 6 } isdnSigTblBchannelCount OBJECT-TYPE SYNTAX Integer32 (1..65535) MAX-ACCESS read-write STATUS current DESCRIPTION "The total number of B channels (bearer channels) managed by this signalling interface." ::= { isdnSignallingTableEntry 7 } isdnSigTblOperStatus OBJECT-TYPE SYNTAX INTEGER { inactive (1), l1_active (2), l2_active (3), l3_active (4) } Expires April 1996 [Page 24] INTERNET-DRAFT ISDN MIB October 1995 MAX-ACCESS read-only STATUS current DESCRIPTION "The operational status of this signalling interface: inactive all layers are inactive l1_active layer 1 is activated, layer 2 datalink not established l2_active layer 1 is activated, layer 2 datalink established, no layer 3 call activity l3_active layer 1 is activated, layer 2 datalink established, layer 3 engaged in call activity " ::= { isdnSignallingTableEntry 8 } -- Signalling channel statistics table -- There is one entry for each signalling connection -- in this table. -- Note that the ifEntry also has some statistics information. isdnSignallingStatsTable OBJECT-TYPE SYNTAX SEQUENCE OF IsdnSignallingStatsEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "ISDN signalling table containing statistics information for all ISDN signalling interfaces on this managed device. Only statistical information which is not being counted in the ifTable is being defined in this table." ::= { isdnSignallingGroup 2 } isdnSignallingStatsEntry OBJECT-TYPE SYNTAX IsdnSignallingStatsEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "An entry in the ISDN Signalling statistics Table" INDEX { ifIndex } ::= { isdnSignallingStatsTable 1 } IsdnSignallingStatsEntry ::= SEQUENCE { isdnSigStatsLapdPeerSabme Counter32, Expires April 1996 [Page 25] INTERNET-DRAFT ISDN MIB October 1995 isdnSigStatsLapdRecvdFrmr Counter32, isdnSigStatsInCalls Counter32, isdnSigStatsInConnected Counter32, isdnSigStatsOutCalls Counter32, isdnSigStatsOutConnected Counter32, isdnSigStatsChargedUnits Counter32 } isdnSigStatsLapdPeerSabme OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of peer SABME frames received on all data links associated with the D-channel of this interface. This is the number of peer-initiated new connections on this interface." ::= { isdnSignallingStatsEntry 1 } isdnSigStatsLapdRecvdFrmr OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of LAPD FRMR response frames received. This is the number of framing errors on this interface." ::= { isdnSignallingStatsEntry 2 } isdnSigStatsInCalls OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of incoming calls on this interface." ::= { isdnSignallingStatsEntry 3 } isdnSigStatsInConnected OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of incoming calls on this interface which were actually connected." ::= { isdnSignallingStatsEntry 4 } Expires April 1996 [Page 26] INTERNET-DRAFT ISDN MIB October 1995 isdnSigStatsOutCalls OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of outgoing calls on this interface." ::= { isdnSignallingStatsEntry 5 } isdnSigStatsOutConnected OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of outgoing calls on this interface which were actually connected." ::= { isdnSignallingStatsEntry 6 } isdnSigStatsChargedUnits OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "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, will be counted here." ::= { isdnSignallingStatsEntry 7 } -- The B channel (bearer channel) group -- -- Note that disconnects can explicitely be handled using the -- ifStack table. If a connection is to be disconnected, -- the according ifStack entry has to be removed. -- More specific, the ifStackTable entry which binds the high-layer -- ifTable entry (and related dialCtlNbrCfgTable entry) to the -- B channel ifTable entry (and related isdnBearerTable entry) -- during an active call has to be removed. isdnBearerGroup OBJECT IDENTIFIER ::= { isdnMibObjects 3 } isdnBearerTable OBJECT-TYPE SYNTAX SEQUENCE OF IsdnBearerEntry Expires April 1996 [Page 27] INTERNET-DRAFT ISDN MIB October 1995 MAX-ACCESS not-accessible STATUS current DESCRIPTION "This table defines port specific control data for ISDN B channels. Each entry in this table describes one B (bearer) channel." ::= { isdnBearerGroup 1 } isdnBearerEntry OBJECT-TYPE SYNTAX IsdnBearerEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "Configuration information relating to one port. A port is a single B channel." INDEX { ifIndex } ::= { isdnBearerTable 1 } IsdnBearerEntry ::= SEQUENCE { isdnBearerCalledAddress DisplayString, isdnBearerCallingAddress DisplayString, isdnBearerSubAddress DisplayString, isdnBearerIfSpid DisplayString, isdnBearerOperStatus INTEGER } isdnBearerCalledAddress OBJECT-TYPE SYNTAX DisplayString MAX-ACCESS read-write STATUS current DESCRIPTION "The ISDN address for incoming calls which is assigned to this B channel. This can be the EAZ (1TR6), the called number (DSS1) for incoming calls or any other necessary specification for other types of switch protocols. If no address is to be assigned to this interface, this object will be a zero length string." ::= { isdnBearerEntry 1 } isdnBearerCallingAddress OBJECT-TYPE SYNTAX DisplayString MAX-ACCESS read-write STATUS current DESCRIPTION Expires April 1996 [Page 28] INTERNET-DRAFT ISDN MIB October 1995 "The ISDN address for outgoing calls which is assigned to this B channel. This can be the EAZ (1TR6), the calling number (DSS1) for outgoung calls or any other necessary specification for other types of switch protocols. If no address is to be assigned to this interface, or if the address to be assigned is identical to isdnBearerCalledAddress, this object will be a zero length string." ::= { isdnBearerEntry 2 } isdnBearerSubAddress OBJECT-TYPE SYNTAX DisplayString MAX-ACCESS read-write STATUS current DESCRIPTION "The ISDN subaddress assigned to this B channel, according to Q.931. If no subaddress is being used or defined for the signalling protocol being used, this can be a zero length string." ::= { isdnBearerEntry 3 } isdnBearerIfSpid OBJECT-TYPE SYNTAX DisplayString MAX-ACCESS read-write STATUS current DESCRIPTION "The SPID information required to configure a B channel. This information has to be defined in addition to the local number for some switch types. If this object is not required, it will be a zero length string." ::= { isdnBearerEntry 4 } isdnBearerOperStatus OBJECT-TYPE SYNTAX INTEGER { idle (1), connecting (2), connected (3), active (4) } MAX-ACCESS read-only STATUS current DESCRIPTION "The current call control state for this port. Expires April 1996 [Page 29] INTERNET-DRAFT ISDN MIB October 1995 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." ::= { isdnBearerEntry 5 } isdnBearerStatsTable OBJECT-TYPE SYNTAX SEQUENCE OF IsdnBearerStatsEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "This table defines port specific statistics and active call data for ISDN B channels. Each entry in this table describes one B (bearer) channel." ::= { isdnBearerGroup 2 } isdnBearerStatsEntry OBJECT-TYPE SYNTAX IsdnBearerStatsEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "Statistics information relating to one port. A port is a single B channel." INDEX { ifIndex } ::= { isdnBearerStatsTable 1 } IsdnBearerStatsEntry ::= SEQUENCE { isdnBearerStatsPeerAddress DisplayString, isdnBearerStatsPeerSubAddress DisplayString, isdnBearerStatsCallOrigin INTEGER, isdnBearerStatsInfoType INTEGER, isdnBearerStatsMultirate TruthValue, isdnBearerStatsCallSetupTime TimeStamp, isdnBearerStatsCallConnectTime TimeStamp, isdnBearerStatsChargedUnits Integer32 } isdnBearerStatsPeerAddress OBJECT-TYPE SYNTAX DisplayString MAX-ACCESS read-only STATUS current Expires April 1996 [Page 30] INTERNET-DRAFT ISDN MIB October 1995 DESCRIPTION "The ISDN address the current or last call is or was connected to. If the peer ISDN address is not available, this object it will have a length of zero." ::= { isdnBearerStatsEntry 1 } isdnBearerStatsPeerSubAddress OBJECT-TYPE SYNTAX DisplayString MAX-ACCESS read-only STATUS current DESCRIPTION "The ISDN subaddress the current or last call is or was connected to. If the peer subaddress is not available, this object it will have a length of zero." ::= { isdnBearerStatsEntry 2 } isdnBearerStatsCallOrigin OBJECT-TYPE SYNTAX INTEGER { originate(1), answer(2), callback(3) } MAX-ACCESS read-only STATUS current DESCRIPTION "The call origin for the current or last call. If there was no call up to now on this interface, this object will have a value of zero." ::= { isdnBearerStatsEntry 3 } isdnBearerStatsInfoType OBJECT-TYPE SYNTAX INTEGER { speech(1), unrestrictedDigital(2), -- as defined in [5] unrestrictedDigital_56(3), -- with 56k rate adaption restrictedDigital(4), audio_31(5), -- 3.1 kHz audio audio_7(6), -- 7 kHz audio video(7), packetSwitched(8) } MAX-ACCESS read-only STATUS current DESCRIPTION "The Information Transfer Capability for the current Expires April 1996 [Page 31] INTERNET-DRAFT ISDN MIB October 1995 or last call, as defined in [5], chapter 4.5.5, octet 3 of bearer capability information element, combined with the User Rate (as defined in octet 5 and 5a to 5d), if rate adaption is being used. speech(1) refers to a non-data connection, whereas audio_31(5) and audio_7(6) refer to data mode connections. Note that [5], chapter 4.5.5, originaly defined audio_7(6) as '7 kHz audio' and now defines it as 'Unrestricted digital information with tones/announcements'. " ::= { isdnBearerStatsEntry 4 } isdnBearerStatsMultirate OBJECT-TYPE SYNTAX TruthValue MAX-ACCESS read-only STATUS current DESCRIPTION "This flag describes if the current or last call used multirate as defined in [5], chapter 4.5.5. The actual information transfer rate, in detail specified in octet 4.1 (rate multiplier), will be defined in ifSpeed for this interface." ::= { isdnBearerStatsEntry 5 } isdnBearerStatsCallSetupTime OBJECT-TYPE SYNTAX TimeStamp MAX-ACCESS read-only STATUS current DESCRIPTION "The value of sysUpTime when the ISDN setup message for the current or last call was sent or received." ::= { isdnBearerStatsEntry 6 } isdnBearerStatsCallConnectTime OBJECT-TYPE SYNTAX TimeStamp MAX-ACCESS read-only STATUS current DESCRIPTION "The value of sysUpTime when the ISDN connect message for the current or last call was sent or received." ::= { isdnBearerStatsEntry 7 } isdnBearerStatsChargedUnits OBJECT-TYPE Expires April 1996 [Page 32] INTERNET-DRAFT ISDN MIB October 1995 SYNTAX Integer32 MAX-ACCESS read-only STATUS current DESCRIPTION "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 will be zero." ::= { isdnBearerStatsEntry 8 } -- -- conformance information -- isdnMibConformance OBJECT IDENTIFIER ::= { isdnMib 2 } isdnMibCompliances OBJECT IDENTIFIER ::= { isdnMibConformance 1 } isdnMibGroups OBJECT IDENTIFIER ::= { isdnMibConformance 2 } -- compliance statements isdnMibCompliance MODULE-COMPLIANCE STATUS current DESCRIPTION "The compliance statement for entities which implement the ISDN MIB. Note that the isdnMibBasicRateGroup is mandatory only for entities supporting Basic Rate interfaces." MODULE -- this module MANDATORY-GROUPS { isdnMibBasicRateGroup, isdnMibSignallingGroup, isdnMibBearerGroup } OBJECT isdnBasicTblIfType MIN-ACCESS read-only DESCRIPTION "It is conformant to implement this object as read-only." OBJECT isdnBasicTblConnectionType MIN-ACCESS read-only DESCRIPTION "It is conformant to implement this object as read-only." OBJECT isdnSigTblLineTopology Expires April 1996 [Page 33] INTERNET-DRAFT ISDN MIB October 1995 MIN-ACCESS read-only DESCRIPTION "It is conformant to implement this object as read-only. For Primary Rate ISDN interfaces, this object must be implemented as read-only and has to return the value of pointToPoint(1)." ::= { isdnMibCompliances 1 } -- units of conformance isdnMibBasicRateGroup OBJECT-GROUP OBJECTS { isdnBasicTblIfType, isdnBasicTblConnectionType } STATUS current DESCRIPTION "A collection of objects required for ISDN basic rate physical interface configuration and statistics." ::= { isdnMibGroups 1 } isdnMibSignallingGroup OBJECT-GROUP OBJECTS { isdnSigTblPhysInterface, isdnSigTblSignallingProtocol, isdnSigTblLineTopology, isdnSigTblCalledAddress, isdnSigTblCallingAddress, isdnSigTblSubAddress, isdnSigTblBchannelCount, isdnSigTblOperStatus, isdnSigStatsLapdPeerSabme, isdnSigStatsLapdRecvdFrmr, isdnSigStatsInCalls, isdnSigStatsInConnected, isdnSigStatsOutCalls, isdnSigStatsOutConnected, isdnSigStatsChargedUnits } STATUS current DESCRIPTION "A collection of objects required for ISDN signalling interface configuration and statistics." ::= { isdnMibGroups 2 } Expires April 1996 [Page 34] INTERNET-DRAFT ISDN MIB October 1995 isdnMibBearerGroup OBJECT-GROUP OBJECTS { isdnBearerCalledAddress, isdnBearerCallingAddress, isdnBearerSubAddress, isdnBearerIfSpid, isdnBearerOperStatus, isdnBearerStatsPeerAddress, isdnBearerStatsPeerSubAddress, isdnBearerStatsCallOrigin, isdnBearerStatsInfoType, isdnBearerStatsMultirate, isdnBearerStatsCallSetupTime, isdnBearerStatsCallConnectTime, isdnBearerStatsChargedUnits } STATUS current DESCRIPTION "A collection of objects required for ISDN bearer channel interface control and statistics." ::= { isdnMibGroups 3 } END Expires April 1996 [Page 35] INTERNET-DRAFT ISDN MIB October 1995 5. Acknowledgements This document was produced by the ISDN MIB Working Group. Special thanks is due to the following persons: Ed Alcoff Fred Baker Bibek A. Das Ken Grigg Jeffrey T. Johnson Glenn Kime Oliver Korfmacher Kedar Madineni Bill Miskovetz David M. Piscitello Lisa A. Phifer Randy Roberts Hascall H. Sharp Robert Snyder Ron Stoughton James Watt 6. References [1] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Structure of Management Information for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1442, SNMP Research,Inc., Hughes LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon University, April 1993. [2] McCloghrie, K., and M. Rose, Editors, "Management Information Base for Network Management of TCP/IP-based internets: MIB-II", STD 17, RFC 1213, Hughes LAN Systems, Performance Systems International, March 1991. [3] Galvin, J., and K. McCloghrie, "Administrative Model for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1445, Trusted Information Systems, Hughes LAN Systems, April 1993. [4] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol Operations for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1448, SNMP Research,Inc., Hughes LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon University, April 1993. Expires April 1996 [Page 36] INTERNET-DRAFT ISDN MIB October 1995 [5] ITU-T Recommendation "Digital subscriber Signalling System No. 1 (DSS 1) - ISDN user-network interface layer 3 specification for basic call control", Rec. Q.931(I.451), March 1993 [6] ITU-T Recommendation "Generic procedures for the control of ISDN supplementary services ISDN user-network interface layer 3 specification", Rec. Q.932(I.452) [7] ITU-T Recommendation "Digital subscriber Signalling System No. 1 (DSS 1) - Signalling specification for frame-mode basic call control", Rec. Q.933 7. Security Considerations Security issues are not discussed in this memo. 8. Author's Address Guenter Roeck Conware GmbH Killisfeldstrasse 64 76137 Karlsruhe, Germany Phone: (49) 721 9495-0 Email: roeck@conware.de Expires April 1996 [Page 37] INTERNET-DRAFT ISDN MIB October 1995 Table of Contents 1 Introduction .................................................... 2 2 The SNMPv2 Network Management Framework ......................... 3 2.1 Object Definitions ............................................ 3 3 Overview ........................................................ 4 3.1 Structure of MIB .............................................. 4 3.1.1 General Description ......................................... 4 3.2 Relationship to RFC 1573 ...................................... 5 3.2.1 Layering Model .............................................. 5 3.2.2 ifTestTable ................................................. 7 3.2.3 ifRcvAddressTable ........................................... 7 3.2.4 ifEntry ..................................................... 8 3.2.4.1 ifEntry for a Basic Rate hardware interface ............... 8 3.2.4.2 ifEntry for a D channel (signalling channel) .............. 9 3.2.4.3 ifEntry for a B channel (bearer channel) .................. 11 3.3 ISDN interface specific information ........................... 13 3.3.1 ISDN leased lines ........................................... 13 3.3.2 Hyperchannels ............................................... 13 3.3.3 D channel backup and NFAS trunks ............................ 13 3.3.4 X.25 data transfer in D channel ............................. 14 3.3.5 SPID handling ............................................... 14 3.3.6 Closed User Groups .......................................... 15 3.3.7 Provision of point-to-point line topology ................... 15 3.3.8 Speech and audio bearer capability information elements ..... 15 4 Definitions ..................................................... 17 5 Acknowledgements ................................................ 36 6 References ...................................................... 36 7 Security Considerations ......................................... 37 8 Author's Address ................................................ 37 Expires April 1996 [Page 38]