CURRENT_MEETING_REPORT_
Reported by Ed Alcoff/Combinet and Guenter Roeck/Conware
Minutes of the ISDN MIB Working Group (ISDNMIB)
Executive Summary
The working group met twice to discuss the most recent Internet-Draft
<draft-ietf-isdnmib-snmp-isdn-mib-00.txt> for the ISDN MIB
specification under development. Several open issues were identified
and discussed. Approximately 22 participants were present at the first
meeting.
Deliverables
The ISDN MIB deliverables will consist of two documents: Call Control
MIB and ISDN MIB. The next Internet-Draft is to delivered no later than
30 September 1995.
Minutes
The following changes to the current Internet-Draft were proposed and
accepted:
ISDN MIB
o Change the OID in the isdnMib MODULE-IDENTITY from fexperimental
98g to ftransmission 20g for the ISDN MIB and ftransmission 21g for
the Call Control MIB as listed in RFC 1573.
o Will coordinate with RFC 1573, and will use ifIndex as an index to
other MIBs, which will also require ifIndex to be included with the
IMPORTS.
o Remove the object isdnFirmwareVersion.
o The isnSubTblDchannelIndex needs to have a MAX-ACCESS of
``read-write.'' Also, isdnSubTblIfAddress would be changed so as
not to include both an address and a subaddress, and a new object,
isdnSubTblIfSubAddress will be defined.
Action: The editor understands the changes as described above.
o To designate ISDN switch types, an IANA-approved designator should
be used.
Action: The working group chair will apply to IANA.
o The object isdnSubTblFlags will be removed.
o Change the name of isdnSubscriberStatsTable to isdnSignallingTable
and remove the following objects:
- isdnSubStatsLapdUnsolicResp
- isdnSubStatsLapdN200Errors
- isdnSubStatsLapdNrSeqErrors
- isdnSubStatsLapdCntlErrors
- isdnSubStatsLapdInfoErrors
- isdnSubStatsLapdWrongSize
- isdnSubStatsLapdN201Errors
o Change the DESCRIPTION for isdnSubStatsLapdPeerSabme to:
``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.''
o The isdnPortTable will be renamed to the isdnBearerTable with the
following changes:
- Delete isdnPortSubIfIndex and use the ifStackTable
- Delete isdnPortIfIndex and use ifIndex
- Add object for subaddress
- Add SPID object for B and/or D channels
- Delete isdnPortAdminStatus and use ifStacktable
(treat as ``up'' for routing status, but do not send messages)
Ed Alcoff asked if an object is needed for the Directory Number?
Action: The editor understands the changes as described above. A
question about Directory Number object will be posed to the mailing
list.
o The enumerated values for the object isdnPortOperStatus will be
limited to idle(1), connecting(2), connected(3) and active(4). A
description of each of these states will be added.
o Add object isdnPortRemoteSubAddress after the object
isdnPortRemoteAddress.
o The object isdnPortcause will have a pointer to the History Table.
o isdnPortInfoType DESCRIPTION clause needs to provide brief text on
the difference between ``speech'' and ``audio.''
o Change isdnPortInfoRate to isdnPortMultiRate. tr_multirate(5) needs
to be of type BOOLEAN.
There was agreement that ifSpeed from RFC 1573 needs to have a
MAX-ACCESS of read-write for an ISDN neighbor. (To represent the
actual speed of an interface).
o isdnPortChargedUnits will be removed as it is a part of the History
Table.
Action: The editor understands the changes as described above.
o For NFAS (Non-Facility Associated Signalling), the ifStackTable
shall be used and an explanation of how this maps will be provided.
Simply shown:
_________
| |
| D ch |
| |
_________
| |
1st entry | | 2nd entry
| |
_________ | ________
| | | |
| T-1 | | T-1 |
| | | |
_________ ________
o After discussions in the TRUNKMIB Working Group, the following
changes were proposed by Guenter Roeck and Fred Baker:
- No RowStatus object in isdnSignallingTable, since there will be
no RowStatus object in the Trunk MIB. Row creation will be
handled as in the Trunk MIB.
- Since we have a physical interface for Primary Rate Interfaces,
we also need a physical interface for Basic Rate Interfaces.
This will need an interface type of ``ISDN basic rate'' to be
assigned by IANA.
[Note: It is not clear at this time if we will need two
interface types, one for S0 interfaces and one for UP0
interfaces. This has to be discussed on the mailing list.]
Action: This will be discussed on the mailing list.
- To be able to handle the basic rate interfaces, we will need a
new table in the MIB, describing such interfaces. It will be
named isdnBasicRateTable and be used to describe physical
interfaces.
- Since the isdnSignallingTable is now used to describe a
signalling protocol entity (D channel), leased line information
does not belong in this table. This information will be
removed. ISDN leased lines can now be handled using the new
physical interface table.
Call Control MIB
o Discussion started with the Call Control MIB, which will now be
called Dial Control MIB.
Fred Baker described how the neighbor table fits into the overall
system structure. This will have to be described and clarified in
much more detail in the MIB.
In Fred's approach, it is not possible to accept incoming calls if
no neighbor table entry exists. Fred thinks this is necessary for
router systems. The MIB should not rely on this, since not all
vendors might think so and there might be systems where this does
not apply.
Action: The editor understands the changes as described above.
o Rina Nathaniel wanted to have an additional table in the MIB, named
phoneDirectoryTable and describing a list of phone numbers, to
avoid several tables with the same objects. The working group did
not agree with this opinion, for security reasons, and that it is
not required.
[Note: Maybe we should note that having objects in a MIB does not
mean there is a need to have the actual data several times. Or is
this implementation experience? ]
Action: This will be discussed on the mailing list.
o David Perkins will send a note concerning NbrId; he wants to limit
the INTEGER to 64k entries. The working group did not agree with
this; a limit of 2^31 will be defined.
o Time definitions will be changed to TimeStamp as appropriate.
Usage of RTC times (time since 1/1/70) is not a good idea since not
all systems will support a RTC.
Action: The editor understands the changes as described above.
o The description element ``UNITS'' will be removed from the MIB; it
is not part of the SMI for SNMPv2.
o Additional objects in the NbrTable will be:
- NbrCarrierDelay with DEFVAL 0; 0 will mean that the call
timeout as specified for the media in question will apply.
- NbrRetryDelay
- NbrDelayAfterFailure
There will be a description added to the text describing what
is expected to happen if a neighbor cannot be reached. In this
case, we expect the ifOperState to change to down to have an
interface down trap generated. The interface should be put
into up or dormant state only if the neighbor in question can
be reached again.
- NbrMinDuration
This will be defined as the ``Minimum duration of a call,
starting from the time the call is connected until the call is
disconnected.'' This is to accomplish the fact that in most
countries charging applies to units of time, which should be
matched as closely as possible.
- NbrTotalChargedUnits
This object will define the total amount of charging units
applying to this neighbor. Only the charging units which apply
to the local interface, i.e., for originated calls or calls
with ``Advice of Charge'' being active, will be counted here.
- NbrTotalConnectTime
- NbrSubAddress -- Same definition as in isdnBearerTable.
Action: The editor understands the changes as described above.
o Fred Baker wanted the NbrIfType object definition to be changed to
refer to ifType. It has to checked by the editor if the ifType
definition applies to this; the working group had some doubts about
it.
Action: The editor will research this.
o Neighbor table will be indexed by NbrLogIf.
The usage of both NbrId and NbrLogIf will have to be clarified.
NbrId specifies a neighbor, and there may be multiple entries into
this table for a single neighbor, thus permitting backup lines as
well as multilink.
o ACC wanted to have NbrAddress specified as OCTET STRING instead of
DisplayString. The working group could not figure out why this
might be necessary; this has to be clarified on the mailing list.
Action: This will be discussed on the mailing list.
o NbrAddress will be split into OriginateAddress, which is the
address being called if a call is originated, and AnswerAddress,
the address which is being passed from the PBX or switch for
incoming calls.
o NbrInfoType and NbrInfoRate will be replaced by an integer
describing the desired speed in bit/second for this neighbor.
Action: The editor understands the changes as described above.
o The enumeration of NbrPermission will be changed to originate(1),
answer(2), both(3) and callback(4).
It will have to be clarified in more detail text that callback(4)
is supposed to control charging, not security, and applies to
callback prior to accepting a call. Callback for security reasons
can be handled using PPP callback.
o David or Ian [from Spider Systems] wanted to have another
enumeration, callback-request, which is supposed to call a neighbor
and explicitly expect a reject. The working group had doubts if
this cannot be handled using both(3).
Action: This will be discussed on the mail list.
o NbrClearReason, NbrClearCode and NbrLastAttempt will be removed.
There will be a new object pointing to the respective entry in the
history table.
Action: The editor understands the changes as described above.
Call History MIB
o The call control and call history MIBs will be merged to a single
MIB.
o The call history MIB will be used to store completed calls, and to
store call attempts as well. This is required since the neighbor
table and Bearer channel table both point into this MIB and it is
supposed to be used to log both types of information.
o If the call history MIB is defined to be empty (to have no history
entries at all), the respective statistics information related to
the last call or call attempt will not be saved.
o The limits for callHistoryTableMaxLength and callHistoryRetainTimer
will be replaced by 2^31.
o callHistoryCalledNumber will be removed.
o callHistoryCallingNumber will be replaced by callHistoryPeerAddress
and
callHistoryPeerSubadress.
o Concerning callHistoryStartTime, callHistoryConnectTime and
callHistoryDisconnectTime, the editor will send mail to the list
stating that there are three objects and two of them seem to be
redundant.
Since there is a small difference between StartTime and
ConnectTime, the working group will have to decide if one of those
objects can be removed. The difference will be described in detail
in the mail.
o The usage of callHistoryIntefaceNumber to be the ifIndex of the
according neighbor table entry will have to be clarified.
o A new object named callHistoryPhysIfIndex will be added, describing
the physical interface the call was attached to.
o callHistoryDestinationAddress and callHistoryDestinationHostName
will be removed.
o callHistoryDisconnectCause will be defined as an OCTET STRING, as
X.21 may use than one character (up to 3) to describe the
disconnect reason.
o There will be a new object in the table, describing the disconnect
reason in text form (callHistoryDisconnectText or equivalent).
Action: The editor understands the changes as described above.