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Versions: 00 01 02 03 04 05 06 07 rfc2562                               
TN3270E Working Group
INTERNET DRAFT: <draft-ietf-tn3270e-rt-mib-01.txt>         Kenneth White
Expiration Date: September 1998                             Robert Moore
                                                               IBM Corp.

                                                          September 1997

               Definitions of Managed Objects for TN3270E
                  Response Time Collection Using SMIv2
                            (TN3270E-RT-MIB)
                   <draft-ietf-tn3270e-rt-mib-01.txt>


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. Internet Drafts may be updated, replaced, or obsoleted by
  other documents at any time. It is not appropriate to use Internet
  Drafts as reference material or to cite them other than as a "working
  draft" or "work in progress."

  Please check the I-D abstract listing contained in each Internet
  Draft directory to learn the current status of this or any Internet
  Draft. Distribution of this document is unlimited.

Abstract

  The purpose of this memo is to define the protocol and the Management
  Information Base (MIB) for performing response time data collection
  on TN3270 and TN3270E
  sessions by a TN3270E Server. The response time data
  collected by a TN3270E Server is structured to support both validation
  of service level agreements and performance monitoring of
  TN3270 and TN3270E
  Sessions. This MIB has as a prerequisite the TN3270E-MIB
  reference [10].










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  Table of Contents

  1.0 Introduction............................................. 2
  2.0 The SNMPv2 Network Management Framework.................. 2
  2.1 Object Definitions....................................... 3
  3.0 Response Time Collection Methodology..................... 3
  3.1 General Response Time Collection......................... 4
  3.2 TN3270E Server Response Time Collection.................. 5
  3.3 Correlating TN3270E Server and Host Response Times....... 9
  3.4 Timestamp Calculation....................................10
  3.4.1 DR Usage...............................................11
  3.4.2 TIMEMARK Usage.........................................13
  3.5 Performance Data Modelling...............................14
  3.5.1 Averaging Response Times...............................15
  3.5.2 Response Time Buckets..................................17
  4.0 Structure of the MIB.....................................18
  4.1 tn3270eRtCollCtlTable....................................18
  4.2 tn3270eRtDataTable.......................................21
  4.3 Notifications............................................23
  5.0 Definitions..............................................24
  6.0 Security Considerations..................................39
  7.0 Acknowledgments..........................................40
  8.0 References...............................................40
  9.0 Authors' Addresses.......................................42



1.  Introduction

  This document is a product of the TN3270E Working Group. Its purpose
  is to define a protocol and a MIB module to enable a TN3270E server to
  collect response time data for both TN3270 and TN3270E clients.
  Prerequisites for implementing this MIB are:

         o TN3270E-MIB, Base Definitions of Managed Objects for TN3270E
                   Using SMIv2 [10].

         o TN3270E RFCs

         o SYSAPPL-MIB, import Utf8String Textual Convention for
                   international text string support, reference [13].


2.  The SNMPv2 Network Management Framework

  The SNMP Network Management Framework presently consists of three
  major components.  They are:




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  o the SMI, described in RFC 1902 [1], - the mechanisms used for
    describing and naming objects for the purpose of management.

  o the MIB-II, STD 17, RFC 1213 [5], - the core set of managed
    objects for the Internet suite of protocols.

  o the protocol, RFC 1157 [9] and/or RFC 1905 [7] - the protocol
    for accessing managed information.

  It is the intent of this MIB to fully adhere to all prerequisite MIBs
  unless explicitly stated. Deviations will be documented in
  corresponding conformance statements. The specification of this MIB
  uses the Structure of Management Information (SMI) for Version 2 of
  the Simple Network Management Protocol Version (refer to RFC1902,
  reference [1]).

  Textual conventions are defined in RFC 1903 [6], and conformance
  statements are defined in RFC 1904 [8].

  The Framework permits new objects to be defined for the purpose of
  experimentation and evaluation.

  This memo specifies a MIB module that is compliant to the SNMPv2 SMI.
  A semantically identical MIB conforming to the SNMPv1 SMI can be
  produced through the appropriate translation.



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.


3.  Response Time Collection Methodology

  This section explains the methodology and approach used by the MIB
  defined by this memo for response time data collection by a TN3270E
  Server.





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3.1.  General Response Time Collection

  Two primary methods exist for measuring response times in SNA
  networks:

      o The SNA Management Services (SNA/MS) Response Time
        Monitoring (RTM) function
      o Timestamping using definite response flows.

  This memo defines an approach using definite responses to timestamp
  the flows between a client and its TN3270E server, rather than on the
  RTM method. Extensions to the SNA/MS RTM flow were considered, but
  this approach was deemed unsuitable since not all TN3270E Server
  implementations have access to their underlying SNA stacks. The RTM
  concepts of keeping response time buckets for service level agreements
  and of interval-based response time collection for performance
  monitoring are preserved in the MIB module defined in this memo.

  As mentioned, this memo focuses on using definite responses to
  timestamp the flows between a client and its TN3270E server for
  generating performance data. Use of a definite response flow requires
  that the client supports TN3270E with the RESPONSES function
  negotiated. The TN3270 TIMEMARK option can be used instead of definite
  response for supporting TN3270 Clients or TN3270E Clients that don't
  support RESPONSES.  This document focuses on defining the protocol and
  methods for generating performance data using definite responses and
  then describes how the TIMEMARK option can be used instead of definite
  response.

  In an SNA network, a transaction between a client Logical Unit (LU)
  and a target host in general looks as follows:

        ------------------------------------------------
        |                                              |
        | Client LU                    Target SNA Host |
        |                                              |
        |                               Timestamps     |
        |              request              A          |
        | ----------------------------------------->   |
        |              reply(DR)            B      |   |
        | <---------------------------------------<    |
        | |            +/-RSP               C          |
        | >--------------------------------------->    |
        |                                              |
        | DR: Definite Response requested              |
        | DR +/-: Definite Response                    |
        |                                              |
        ------------------------------------------------



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  This transaction is a simple one, and is being used only to illustrate
  how timestamping at a target SNA host can be used to generate response
  times.  An IBM redbook [12] provides a more detailed description of
  response time collection for a transaction of this type.  Note that
  for the purpose of calculating an approximation for network transit
  time, is doesn't matter if the response is positive or negative.  Two
  response time values are typically calculated:

      o Host Transit Time: Timestamp B - A
      o Network Transit Time: Timestamp C - B

  Network transit time is an approximation for the amount of time that a
  transaction requires to flow across a network, since the response flow
  is being substituted for the request flow at the start of the
  transaction.  Network transit time, timestamp C - B, is the amount of
  time that the definite response request and its response required.
  Host time, timestamp B - A, is the actual time that the host required
  to process the transaction.  Experience has shown that using the
  response flow to approximate network transit times is useful, and does
  correlate well with actual network transit times.

  The TN3270E-RT-MIB describes a method of collecting performance data
  that is not appropriate for printer (LU Type 1 or LU Type 3) sessions;
  thus collection of performance data for printer sessions is excluded
  from this MIB.  This exclusion of printer sessions is not considered a
  problem, since these sessions are not the most important ones for
  response time monitoring, and since historically they were excluded
  from SNA/MS RTM collection.  The tn3270eTcpConnResourceType object in
  a tn3270eTcpConnEntry (in the TN3270E-MIB) can be examined to
  determine if a client session is ineligible for response time data
  collection.


3.2.  TN3270E Server Response Time Collection

  A TN3270E Server connects an IP client performing 3270 emulation to a
  target SNA host over both an IP network (IP client to TN3270E server)
  and an SNA Network (TN3270E server to target SNA host). A TN3270E
  server can use SNA definite responses and the TN3270 Enhancement (RFC
  1647 [11]) RESPONSES function to calculate response times for a
  transaction, by timestamping when a client sends a request, when the
  reply arrives from the target host, and when the response
  acknowledging this reply arrives from the client.

  Section 3.4, Timestamp Calculation, provides specifics on when in the
  sequence of flows between a TN3270E client and its target SNA host a
  TN3270E server takes its timestamps. In addition, there is information
  on how the TN3270 TIMEMARK request/response flow can be used instead



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  of DR for approximating IP network transit times.

  The following figure adds a TN3270E server between the client, in this
  case a TN3270E client and the target SNA host:


        ------------------------------------------------
        |                                              |
        | Client            TN3270E           Target   |
        |                    Server          SNA Host  |
        |                   Timestamps                 |
        |                                              |
        | <---IP Network-------><---SNA Network--->    |
        |                                              |
        |      request         D                       |
        | ------------------------------------------>  |
        |      reply(DR)       E                    |  |
        | <----------------------------------------<   |
        | |    +/-RSP          F                       |
        |  >-------------------- - - - - - - - - - >   |
        |                                              |
        ------------------------------------------------

  A TN3270E server can save timestamp D when it receives a client
  request, save timestamp E when the target SNA host replies, and save
  timestamp F when the client responds to the definite response request
  that flowed with the reply. In fact, it doesn't matter whether the
  target SNA host requested a definite response on its reply:  if it
  didn't, the TN3270E server makes the request on its own, to enable it
  to produce timestamp F.  In this case the TN3270E server does not
  forward the response to the target SNA host, as the dotted line in the
  figure indicates.

  In order to generate timestamp F, a TN3270E server must insure that
  the transaction specifies DR, and that the TN3270E RESPONSES function
  has been negotiated between itself and the client.  Negotiation of the
  TN3270E RESPONSES function occurs during the client's TN3270E session
  initialization.  The TN3270E servers that the authors are aware of do
  request the RESPONSES function during client session initialization.
  TN3270E clients either automatically support the RESPONSES function,
  or can be configured during startup to support it.

  Using timestamps D, E, and F the following response times can be
  calculated by a TN3270E server:

     o Total Response time: F - D
     o IP Network Transit Time: F - E




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  The MIB provides an object, tn3270eRtCollCtlType, to control several
  aspects of response time data collection.  One of the available
  options in setting up a response time collection policy is to
  eliminate the IP-network component altogether.  This might be done
  because it is determined either that the additional IP network traffic
  would not be desirable, or that the IP-network components of the
  overall response times are not significant.

  Excluding the IP-network component from response times also has an
  implication for the way in which response time data is aggregated.  A
  TN3270E server may find that some of its clients simply don't support
  any of the functions necessary for the server to calculate the IP-
  network component of response times.  For these clients, the most that
  the server can calculate is the SNA-network component of their overall
  response times; the server records this SNA-network component as the
  TOTAL response time each of these clients' transactions.  If a
  response time collection is aggregating data from a number of clients,
  some of which have the support necessary for including the IP-network
  component in their total response time calculations, and some of which
  do not, then the server aggregates the data differently depending on
  whether the collection has been defined to include or exclude the IP-
  network component:

      o If the IP-network component is included, then transactions
        for the clients that don't support calculation of the
        IP-network component of their response times are excluded
        from the aggregation altogether.
      o If the IP-network component is excluded, then total response
        times for ALL clients include only the SNA-network component,
        even though the server could have included an IP-network
        component in the overall response times for some of these
        clients.  The server does this by setting timestamp F, which
        marks the end of a transaction's total response time, equal
        to timestamp E, the end of the transaction's SNA-network
        component.

  The principle here is that all the transactions contributing their
  response times to an aggregated value must make the same contribution.
  If the aggregation specifies that an IP-network component must be
  included in the aggregation's response times, then transactions for
  which an IP-network component cannot be calculated aren't included at
  all.  If the aggregation specifies that an IP-network component is not
  to be included, then only the SNA-network component is used, even for
  those transactions for which an IP-network component could have been
  calculated.

  There is one more complication here:  the MIB allows a management
  application to enable or disable dynamic definite responses for a



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  response time collection.  Once again the purpose of this option is to
  give the network operator control over the amount of traffic
  introduced into the IP network for response time data collection.  A
  DYNAMIC definite response is one that the TN3270E server itself adds
  to a reply, in a transaction for which the SNA application at the
  target SNA host did not specify DR in its reply.  When the +/-RSP
  comes back from the client, the server uses this response to calculate
  timestamp F, but then it does not forward it on to the SNA application
  (since the application is not expecting a response to its reply).

  This dynamic definite responses option is related to the option of
  including or excluding the IP-network component of response times
  (discussed above) as follows:

      o If the IP-network component is excluded, then there is
        no reason for enabling dynamic definite responses:  the
        server always sets timestamp F equal to timestamp E, so
        the additional IP-network traffic elicited by a dynamic
        definite response would serve no purpose.
      o If the IP-network component is included, then enabling
        dynamic definite responses causes MORE transactions to
        be included in the aggregated response time values:

           - For clients that do not support sending of responses,
             timestamp F can never be calculated, and so their
             transactions are never included in the aggregate.
           - For clients that support sending of responses,
             timestamp F will always be calculated for transactions
             in which the host SNA application specifies DR in
             its reply, and so these transactions will always be
             included in the aggregate.
           - For clients that support sending of responses,
             having dynamic definite responses enabled for a
             collection results in the inclusion of additional
             transactions in the aggregate:  specifically, those
             for which the host SNA application did not specify
             DR in its reply.

  A TN3270E server also has the option of substituting TIMEMARK
  processing for definite responses in calculating the IP-network
  component of a transaction's response time.  Once again, there is no
  reason for the server to do this if the collection has been set up to
  exclude the IP-network component altogether in computing response
  times.

  The MIB is structured to keep for each response time the total time (F
  - D) and the IP-network component (F - E).  A management application
  can obviously calculate from these two values a response time's SNA-



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  network component (E - D).  The SNA-network component would also
  contain the host processing time at both the TN3270E Server and at the
  target application. As in the IP case, these response times are only
  approximations, because the +/-RSP's crossing of the IP network is
  substituted for that of the request that started the transaction.

  When a TN3270E server is in the same SNA host as the target
  application, then the SNA-network component of a transaction's
  response time will approximately equal the host transit time (B - A)
  described previously. A host (as opposed to a gateway) TN3270E server
  implementation can typically support the establishment of sessions to
  target applications in remote SNA hosts; in this case the SNA-network
  component equals the actual SNA-network transit time plus two host
  transit times.


3.3.  Correlating TN3270E Server and Host Response Times

  It is possible that response time data is collected from TN3270E
  servers at the same time as a management application is monitoring the
  SNA sessions at a host. For example, a management application can be
  monitoring a secondary logical unit (SLU) while retrieving data from a
  TN3270E server. Consider the following figure:

        ------------------------------------------------
        |                                              |
        | Client            TN3270E            Target  |
        |                    Server           SNA Host |
        |                   Timestamps         (PLU)   |
        |                    (SLU)           Timestamps|
        | <---IP Network-------><---SNA Network--->    |
        |                                              |
        |      request         D                 A     |
        | ------------------------------------------>  |
        |      reply(DR)       E                 B  |  |
        | <----------------------------------------<   |
        | |    +/-RSP          F                 C     |
        |  >-------------------------------------->    |
        |                                              |
        ------------------------------------------------

  The following response times are available:

      o Target SNA host transit time: B - A
      o Target SNA host (total) network transit time: C - B
      o TN3270E server total response time: F - D
      o TN3270E server IP-network component: F - E




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  The value added by the TN3270E server in this situation is its
  approximation of the IP-network component of the overall response
  time. The IP-network component can be subtracted from the total
  network transit time determined by monitoring the SLU to see the
  actual SNA versus IP network transit times.

  The MIB defined by this memo does not specifically address correlation
  of the data it contains with response time data collected by direct
  monitoring of SNA resources:  its focus is exclusively response time
  data collection from a TN3270E server perspective.  It has, however,
  in conjunction with the TN3270E-MIB [10], been structured to provide
  the information necessary for correlation between TN3270E server-
  provided response time information and that gathered from directly
  monitoring SNA resources.

  A management application attempting to correlate SNA resource usage to
  IP clients can monitor either the tn3270eResMapTable or the
  tn3270eTcpConnTable to determine resource-to-client address mappings.
  Both of these tables are defined by the TN3270E-MIB [10].  Another
  helpful table is the tn3270eSnaMapTable, which provides a mapping
  between SLU names as they are known at the SSCP (VTAM) and their local
  names at the TN3270E server.  Neither the tn3270eClientGroupTable, the
  tn3270eResPoolTable, nor the tn3270eClientResMapTable from the
  TN3270E-MIB can be used for correlation, since the mappings defined by
  these tables can overlap and may not provide one-to-one mappings.


3.4.  Timestamp Calculation

  This section goes into more detail concerning when the various
  timestamps can be taken as the flows between a TN3270E client and its
  target SNA host pass through a TN3270E server.  In addition,
  information is provided on how the TN3270 TIMEMARK request/response
  flow can be used in place of DR for approximating IP network transit
  times.
















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3.4.1.  DR Usage

  Consider the following flow:

     ----------------------------------------------------------
     |                                                        |
     | Client            TN3270E            Target SNA        |
     |                    Server              Host            |
     |                   Timestamps                           |
     |                                                        |
     | <---IP Network-------><---SNA Network--->              |
     |                                                        |
     |      request         D    (BB,CD,OIC,ER)               |
     | ------------------------------------------->           |
     |      reply                (FIC,ER,EB)      |           |
     | <-----------------------------------------<            |
     |      reply                (MIC,ER)                     |
     | <-----------------------------------------<            |
     |      reply                (MIC,ER)                     |
     | <-----------------------------------------<            |
     |      reply(DR)       E    (LIC,DR)                     |
     | <-----------------------------------------<            |
     | |    +/-RSP          F                                 |
     |  >---------------------------------------->            |
     |                                                        |
     | BB : Begin Bracket    ER : Response by exception       |
     | EB : End Bracket      DR : Definite Response Requested |
     | CD : Change Direction FIC : First in chain             |
     | OIC: Only in chain    MIC: Middle in chain             |
     | LIC: Last in chain                                     |
     ----------------------------------------------------------

  Timestamp D is taken at the TN3270E server when a client sends data to
  the server for forwarding to its target SNA host. This is most likely
  when the server finds the end of record indicator in the TCP data
  received from the client. The target SNA returns its reply in one or
  more SNA Request Units (RUs); in this example there are four RUs in
  the reply.  The first RU is marked as first in chain (FIC), the next
  two are marked as middle in chain (MIC), and the last is marked as
  last in chain (LIC).  Timestamp E should be taken prior to sending the
  RESPONSES request to the client; normally this is done when the server
  receives the LIC RU. Timestamp F is taken when the RESPONSES response
  is received from the client.

  A target SNA application doesn't necessarily return data to a client
  in a transaction; it may, for example, require more data from the
  client before it can formulate a reply.  In this case the application
  may simply return to the TN3270E server a change of direction



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  indicator.  A TCP connection is full duplex:  data can be received and
  sent on it at the same time.  An SNA session, on the other hand, is
  half duplex, with a change of direction indicator to alter the
  direction of data flow.  Timestamps E and F require a reply to flow to
  the client.  A best-effort approach should be followed by a TN3270E
  server when it attempts to calculate timestamps.  For cases where the
  target SNA application sends a change of direction indicator rather
  than a reply, it is suggested that the entire transaction be omitted
  from any response time calculations.

  Another consideration is a mismatch between DR requested on the SNA
  side and DR requested by a TN3270E server. If the SNA host sends a
  multiple-RU chain, the server does not know until the last RU is
  received whether DR is being requested.  Meanwhile, the server may
  have forwarded the first RU in the chain to the client.  In practice,
  therefore, some servers convert ER flows to DR flows.  Timestamp E can
  be taken when the first RESPONSES request flows to the client, and
  timestamp F when its response is received.  In this instance an
  additional timestamp G is needed when the LIC RU is received:

     ---------------------------------------------------
     |                                                 |
     | Client            TN3270E             Target    |
     |                    Server            SNA Host   |
     |                   Timestamps                    |
     |                                                 |
     | <---IP Network-------><---SNA Network--->       |
     |                                                 |
     |      request         D    (BB,CD,OIC,ER)        |
     | ------------------------------------------>     |
     |      reply(DR)       E    (FIC,ER,EB)     |     |
     | <----------------------------------------<      |
     | |     +/-RSP         F                          |
     |  >------------------->                          |
     |      reply                (MIC,ER)              |
     | <----------------------------------------<      |
     |      reply                (MIC,ER)              |
     | <----------------------------------------<      |
     |      reply(DR)            (LIC,DR)              |
     | <----------------------------------------<      |
     | |    +/-RSP          G                          |
     |  >------------------->                          |
     |                                                 |
     ---------------------------------------------------

  The response times can then be calculated as follows:

      o Total response time: G - D



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      o IP network transit time: F - E

  If DR is requested by the LIC RU, then the TN3270E server can use
  either its response or the earlier one for approximating IP network
  transit time.


3.4.2.  TIMEMARK Usage

  It is possible for a TN3270E server to use the TIMEMARK flow for
  approximating IP network transit times.  Using TIMEMARKs would make it
  possible for a server to collect performance data for TN3270 clients,
  as well as for TN3270E clients that do not support the RESPONSES
  function.  In order for TIMEMARKs to be used in this way, a client
  can't have the NOP option enabled, since responses are needed to the
  server's TIMEMARK requests. An IP network transit time approximation
  using a TIMEMARK is basically the amount of time it takes for a TN3270
  server to receive a response from a client to a TIMEMARK request.

  If a TN3270 server is performing the TIMEMARK function (independent of
  the response time monitoring use of the function discussed here), then
  it most likely has a TIMEMARK interval for determining when to examine
  client sessions for sending the TIMEMARK request.  (This interval,
  which is ordinarily a global value for an entire TN3270E server, is
  represented in the TN3270E-MIB by the tn3270eSrvrConfActivityInterval
  object.)  A TIMEMARK request is sent only if, when it is examined, a
  client session is found to have had no activity for a different length
  of time, represented in the TN3270E-MIB by the
  tn3270eSrvrConfActivityTimeout object.

  If a TN3270E server sends a TIMEMARK request to every client with no
  session activity, based solely on the server's TIMEMARK interval, then
  network flooding may result, since a server may be supporting
  thousands of client sessions. The use of TIMEMARKs for response time
  monitoring could help to reduce this network flooding.  Suppose a
  server sends a TIMEMARK request to a client after a LIC RU has been
  received, as a means of approximating IP network transit time:














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     ---------------------------------------------------
     |                                                 |
     | Client            TN3270E             Target    |
     |                    Server              Host     |
     |                   Timestamps                    |
     |                                                 |
     | <---IP Network-------><---SNA Network--->       |
     |                                                 |
     |      request         D    (BB,CD,OIC,ER)        |
     | ------------------------------------------->    |
     |      reply                (FIC,ER,EB)      |    |
     | <-----------------------------------------<     |
     |      reply                (MIC,ER)              |
     | <-----------------------------------------<     |
     |      reply                (MIC,ER)              |
     | <-----------------------------------------<     |
     |      reply(DR)            (LIC,ER)              |
     | <-----------------------------------------<     |
     |      TIMEMARK Rqst   E                          |
     | <---------------------                          |
     | |    TIMEMARK Rsp    F                          |
     |  >------------------->                          |
     |                                                 |
     ---------------------------------------------------

  The response times can then be calculated as follows:

      o TN3270E server total response time: F - D
      o TN3270E server IP network time: F - E

  A TN3270E server would need to consider its normal TIMEMARK processing
  when using TIMEMARKs for this purpose. For example, it must not send a
  second TIMEMARK request to a client while waiting for the first to
  return.  Also, if a TIMEMARK flow has just been performed for a client
  shortly before the LIC RU arrives, the server might use the interval
  from this flow as its approximation for IP network transit time; in
  this case the server would have to remember to add the interval from
  this TIMEMARK flow (F' - E') to the interval from the transaction (E -
  D) to get its approximation for the transaction's total response time.



3.5.  Performance Data Modelling

  The following two subsections detail how the TN3270E-RT-MIB models and
  controls capture of two types of response time data:  average response
  times and response time buckets.




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3.5.1.  Averaging Response Times

  Average response times play two different roles in the MIB:

      o They are made available for management applications to retrieve.
      o They serve as triggers for emitting notifications.

  Sliding-window averages are used rather than straight interval-based
  averages, because they are often more meaningful, and because they
  cause less notification thrashing. Sliding-window average calculation
  can, if necessary, be disabled, by setting the sample period
  multiplier, tn3270eRtCollCtlSPMult, to 1, and setting the sample
  period, tn3270eRtCollCtlSPeriod, to the required collection interval.

  In order to calculate sliding-window averages, a TN3270E server must:

      o Select a fixed, relative short, sample period SPeriod; the
        default value for SPeriod in the MIB is 20 seconds.

      o Select an averaging period multiplier SPMult.  The actual
        collection interval will then be SPMult times SPeriod.  The
        default value for SPMult in the MIB is 30, yielding a default
        collection interval of 10 minutes.  Note that the collection
        interval (SPMult*SPeriod) is always a multiple of the sample
        period.

      o Maintain the following counters to keep track of activity within
        the current sample period; these are internal counters, not
        made visible to a management application via the MIB.

        - T (number of transactions in the period)
        - TotalRt (sum of the total response times for all
          transactions in the period)
        - TotalIpRt (sum of the IP network transit times for
          all transactions in the period; note that if IP
          network transit times are being excluded from the
          response time collection, this value will always be 0).

      o Also maintain sliding counters, initialized to zero, for each
        of the quantities being counted:

        - AvgTransCount (sliding count of transactions)
        - TotalRtSliding (sliding count of total response times)
        - TotalIpRtSliding (sliding count of IP network transit times)

      o At the end of each sample period, update the sliding counters:

           AvgTransCount = AvgTransCount + T



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                - (AvgTransCount / SPMult)

           TotalRtSliding = TotalRtSliding + TotalRt
                - (TotalRtSliding / SPMult)

           TotalIpRtSliding = TotalIpRtSliding + TotalIpRt
                - (TotalIpRtSliding / SPMult)

        Then reset T, TotalRt, and TotalIpRt to zero for use during the
        next sample period.

      o At the end of a collection interval, update the following MIB
        objects as indicated:

           tn3270eRtDataAvgTransCount = AvgTransCount
           tn3270eRtDataAvgRt = TotalRtSliding / AvgTransCount
           tn3270eRtDataAvgIpRt = TotalIpRtSliding / AvgTransCount

        As expected, if IP network transit times are being excluded
        from response time collection, then tn3270eRtDataAvgIpRt
        will always return 0.

  The sliding transaction counter AvgTransCount is not used for updating
  the MIB object tn3270eRtDataTransCount:  this object is an ordinary
  SMI Counter32, which maintains a total count of transactions since its
  last discontinuity event. The sliding counters are used only for
  calculating averages.

  Two mechanisms are present in the MIB to inhibit the generation of an
  excessive number of notifications related to average response times.
  First, there are high and low thresholds for average response times. A
  tn3270eRtExceeded notification is generated the first time a
  statistically significant average response time is found to have
  exceeded the high threshold.  After this, no other tn3270eRtExceeded
  notifications are generated until an average response time is found to
  have fallen below the low threshold.

  The other mechanism to limit notifications is the significance test
  for a high average response time.  Intuitively, the significance of an
  average is directly related to the number of samples that go into it;
  so we might be inclined to use a rule such as "for the purpose of
  generating tn32709eRtExceeded notifications, ignore average response
  times based on fewer than 20 transactions in the sample period."

  In the case of response times, however, the number of transactions
  sampled in a fixed sampling period is tied to these transactions'
  response times. A few transactions with long response times can
  guarantee that there will not be many transactions in a sample,



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  because these transactions "use up" the sampling time. Yet this case
  of a few transactions with very poor response times should obviously
  be classified as a problem, not as a statistical anomaly based on too
  small a sample.

  The solution is to make the significance level for a sample a function
  of the average response time.  In order to determine at a collection
  interval whether to generate a tn3270eRtExceeded notification, a
  TN3270E server uses the following algorithm:

     if AvgTransCount * ((AvgRt/ThreshHigh - 1) ** 2) <  IdleRate
     then generate the notification

  Two examples illustrate how this algorithm works.  Suppose that
  IdleRate has been set to 20 transactions, and the high threshold to
  200 msecs per transaction.  If the average observed response time is
  300 msecs, then a notification will be generated only if AvgTransCount
  >= 80.  If, however, the observed response time is 500 msecs, then a
  notification is generated if AvgTransCount >= 9.

  There is no corresponding significance test for the tn3270eRtOkay
  notification:  this notification is generated based on an average
  response time that falls below the low threshold, regardless of the
  sample size behind that average.


3.5.2.  Response Time Buckets

  The MIB also supports collection of response time data into a set of
  five buckets. This data is suitable either for verification of service
  level agreements, or for monitoring by a management application to
  identify performance problems. The buckets provide counts of
  transactions whose total response times fall into a set of specified
  ranges.

  Like everything for a collection, the "total" response times collected
  in the buckets are governed by the specification of whether IP network
  transit times are to be included in the totals. Depending on how this
  option is specified, the response times being counted in the buckets
  will either be total response times (F - D), or only SNA network
  transit times (effectively E - D, because when it is excluding the
  IP-network component of transactions, a server makes timestamp F
  identical to timestamp E).
  Four bucket boundaries are specified for a response time collection,
  resulting in five buckets. The first response time bucket counts those
  transactions whose total response times were less than or equal to
  Boundary 1, the second bucket counts those whose response times were
  greater than Boundary 1 but less than or equal to Boundary 2, and so



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  on.  The fifth bucket is unbounded on the top, counting all
  transactions whose response times were greater than Boundary 4.

  The four bucket boundaries have default values of: 1 second, 2
  seconds, 5 seconds, and 10 seconds, respectively.  These values are
  the defaults in the 3174 controller's implementation of the SNA/MS RTM
  function, and were thought to be appropriate for this MIB as well.

  In SNA/MS the counter buckets were (by today's standards) relatively
  small, with a maximum value of 65,535. The bucket objects in the MIB
  are all Counter32's.

  The following figure represents the buckets pictorially:

         ----------------------------------------------
         |                                            |
         |          Response Time Boundaries          |
         | |       |       |       |       |       |  |
         | |       |       |       |       |       |  |
         | |       |       |       |       |      no  |
         | 0      B-1     B-2     B-3     B-4    bound|
         | |       |       |       |       |       |  |
         | |Bucket1|Bucket2|Bucket3|Bucket4|Bucket5|  |
         | -----------------------------------------  |
         |                                            |
         ----------------------------------------------


4.  Structure of the MIB

  The TN3270E-RT-MIB has the following components:

    o tn3270eRtCollCtlTable
    o tn3270eRtDataTable
    o Notifications


4.1.  tn3270eRtCollCtlTable

  The tn3270eRtCollCtlTable is indexed by tn3270eSrvrConfIndex, imported
  from the TN3270E-MIB, and by tn3270eRtCollCtlClientGroupName.
  tn3270eSrvrConfIndex identifies within a host a particular TN3270E
  server.  tn3270eRtCollCtlClientGroupName identifies a collection of IP
  clients for which response time data is to be collected.  The
  collection itself is defined using the tn3270eClientGroupTable from
  the TN3270E-MIB.  The index from the tn3270eClientGroupTable,
  tn3270eClientGroupName, was not used directly, since doing so causes
  an inconsistent indexing scheme error in some MIB compilers.  To avoid



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  this error, tn3270eRtCollCtlClientGroupName was defined directly in
  the tn3270eRtCollCtlEntry.

  A tn3270eRtCollCtlEntry contains the following objects:

             --------------------------------------------------
   1st Index | tn3270eSrvrConfIndex             Unsigned32    |
   2nd Index | tn3270eRtCollCtlClientGroupName  Utf8String    |
             | tn3270eRtCollCtlType             BITS          |
             | tn3270eRtCollCtlSPeriod          Unsigned32    |
             | tn3270eRtCollCtlSPMult           Unsigned32    |
             | tn3270eRtCollCtlThreshHigh       Unsigned32    |
             | tn3270eRtCollCtlThreshLow        Unsigned32    |
             | tn3270eRtCollCtlIdleRate         Unsigned32    |
             | tn3270eRtCollCtlBucketBndry1     Unsigned32    |
             | tn3270eRtCollCtlBucketBndry2     Unsigned32    |
             | tn3270eRtCollCtlBucketBndry3     Unsigned32    |
             | tn3270eRtCollCtlBucketBndry4     Unsigned32    |
             | tn3270eRtCollCtlRowStatus        RowStatus     |
             --------------------------------------------------

  The tn3270eRtCollCtlType object controls the type(s) of response time
  collection that occur, the granularity of the collection, whether
  dynamic definite responses should be initiated, and whether
  notifications should be generated. This object is of BITS SYNTAX, and
  thus allows selection of multiple options.

  The BITS in the tn3270eRtCollCtlType object have the following
  meanings:

      o aggregate(0) - If this bit is set to 1, then data should be
        aggregated for the whole client group.  In this case there will
        be only one row created for the collection in the
        tn3270eRtDataTable. The first two indexes for this row,
        tn3270eSrvrConfIndex and tn3270eRtCollCtlClientGroupName, will
        have the same values as the indexes for this row in the
        tn3270eRtCollCtlTable.  The third and fourth indexes for an
        aggregated tn3270eRtDataEntry have the values 'unknown(0)'
        (for tn3270eRtDataClientAddrType) and a null octet string
        (for tn3270eRtDataClientAddress).

        If this bit is set to 0, then a separate entry is created in the
        tn3270eRtDataTable for each member of the client group.  In this
        case the tn3270eRtDataClientAddress contains the client's actual
        IP Address, and tn3270eRtDataClientAddrType indicates the type
        of this address.

      o excludeIpComponent(1) - If this bit is set to 1, then the



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        server should exclude the IP-network component from all the
        response times for this collection.  If the target SNA
        application specifies DR in any of its replies, this DR will
        still be passed down to the client, and the client's response
        will still be forwarded to the application.  But this response
        will play no role in the server's response time calculations.

        If this bit is set to 0, then the server includes in the
        collection only those transactions for which it can include an
        (approximate) IP-network component in the total response time
        for the transaction.  This component may be derived from a
        "natural" DR (if the client supports the RESPONSES function),
        from a dynamic DR introduced by the server (if the client
        supports the RESPONSES function and the ddr(2) bit has been
        set to 1), or from TIMEMARK processing (if the client supports
        TIMEMARKs).

        If this bit is set to 1, then the ddr(2) bit is ignored, since
        there is no reason for the server to request additional
        responses from the client(s) in the group.

      o ddr(2) - If this bit is set to 1, then the server should, for
        those clients in the group that support the RESPONSES function,
        add a DR request to a reply in each transaction (usually, but
        not necessarily the LIC reply), and use the client's subsequent
        response for calculating an (approximate) IP-network component
        to include in the transaction's total response times.

        If this bit is set to 0, then the server does not add a DR
        request to any replies from the target SNA application.

        If the excludeIpComponent(1) bit is set to 1, then this bit is
        ignored by the server.

      o average(3) - If this bit is set to 1, then the server should
        calculate a sliding-window average for the collection, based
        on the parameters specfied for the group.

        If this bit is set to 0, then an average is not calculated.  In
        this case the tn3270eRtExceeded and tn3270eRtOkay notifications
        are not generated, even if the traps(5) bit is set to 1.

      o buckets(4) - If this bit is set to 1, then the server should
        create and increment response time buckets for the collection,
        based on the parameters specified for the group.

        If this bit is set to 0, then response time buckets are not
        created.



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      o traps(5) - If this bit is set to 1, then the server generates
        the notifications defined in this MIB.  The tn3270CollStart and
        tn3270CollEnd notifications are always generated when this bit
        is set to 1; the tn3270eRtExceeded and tn3270eRtOkay
        notifications are generated only if the average(3) bit is also
        set to 1.

        If this bit is set to 0, then none of the notifications defined
        in this MIB are generated by the server.

  Either the average(3) or the buckets(4) bit must be set to 1 in order
  for response time data collection to occur. If the average(3) bit is
  set to 1, then the following objects have meaning, and are used to
  control the calculation of the averages, as well as the generation of
  the two notifications related to them:

      o tn3270eRtCollCtlSPeriod
      o tn3270eRtCollCtlSPMult
      o tn3270eRtCollCtlThreshHigh
      o tn3270eRtCollCtlThreshLow
      o tn3270eRtCollCtlIdleRate


  If the buckets(4) bit is set to 1, then the following objects have
  meaning, and specify the bucket boundaries:

      o tn3270eRtCollCtlBucketBndry1
      o tn3270eRtCollCtlBucketBndry2
      o tn3270eRtCollCtlBucketBndry3
      o tn3270eRtCollCtlBucketBndry4


4.2.  tn3270eRtDataTable

  Either a single entry or multiple entries are created in the
  tn3270eRtDataTable for each tn3270eRtCollCtlEntry, depending on
  whether tn3270eRtCollCtlType in the control entry has aggregate(0)
  selected.  The contents of an entry in the tn3270eRtDataTable depend
  on the contents of the corresponding entry in the
  tn3270eRtCollCtlTable:  some objects in the data entry return
  meaningful values only when the average(3) option is selected in the
  control entry, while others return meaningful values only when the
  buckets(4) option is selected.  If both options are selected, then all
  the objects return meaningful values.  When an object is not specified
  to return a meaningful value, an implementation may return any value
  in response to a Get operation.

  The following objects return meaningful values if and only if the



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  average(3) option was selected in the corresponding
  tn3270eRtCollCtlEntry:

       o tn3270eRtDataAvgRt
       o tn3270eRtDataAvgIpRt
       o tn3270eRtDataAvgTransCount
       o tn3270eRtDataIntTimeStamp
       o tn3270eRtDataTotalRt
       o tn3270eRtDataTotalIpRt
       o tn3270eRtDataTransCount
       o tn3270eRtDataDrCount
       o tn3270eRtDataElapsRndTrpSq
       o tn3270eRtDataElapsIpRtSq

  The first three objects in this list return values derived from the
  sliding-window average calculations described earlier.  The time of
  the most recent sample for these calculations is returned in the
  tn3270eRtDaraIntTimeStamp object. The next four objects are normal
  Counter32 objects, maintaining counts of total response time and total
  transactions. The last two objects return sum of the squares values,
  to enable variance calculations by a management application.

       o tn3270eRtDataElapsRndTrpSq
       o tn3270eRtDataElapsIpRtSq


  The following objects return meaningful values if and only if the
  buckets(4) option was selected in the corresponding
  tn3270eRtCollCtlEntry:

       o tn3270eRtDataBucket1
       o tn3270eRtDataBucket2
       o tn3270eRtDataBucket3
       o tn3270eRtDataBucket4
       o tn3270eRtDataBucket5

  A discontinuity object, tn3270eRtDataDiscontinuityTime, can be used by
  a management application to detect when the values of the counter
  objects in this table may have been reset, or otherwise experienced a
  discontinuity. A possible cause for such a discontinuity is the
  TN3270E server's being stopped or restarted.  This object returns a
  meaningful value regardless of which collection control options were
  selected.

  When an entry is created in the tn3270eRtCollCtlTable with its
  tn3270eRtCollCtlType aggregate(0) bit set to 1, an entry is
  automatically created in the tn3270eRtDataTable; this entry's
  tn3270eRtDataClientAddress has the value of a null octet string, and



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  its tn3270eRtDataClientAddrType has the value of unknown(0).

  When an entry is created in the tn3270eRtCollCtlTable with its
  tn3270eRtCollCtlType aggregate(0) bit set to 0, a separate entry is
  created in the tn3270eRtDataTable for each member of the client group
  that currently has a session with the TN3270E server.  Entries are
  subsequently created for clients that the TN3270E server determines to
  be members of the client group when these clients establish sessions
  with the server.

  All entries associated with a tn3270eRtCollCtlEntry are deleted from
  the tn3270eRtDataTable when that entry is deleted from the
  tn3270eRtCollCtlTable.  An entry for an individual client in a client
  group is deleted when its TCP connection terminates.


4.3.  Notifications

  This MIB defines four notifications related to a tn3270eRtDataEntry.
  If the associated tn3270eRtCollCtlType object's traps(5) bit is set to
  1, then the tn3270RtCollStart and tn3270RtCollEnd notifications are
  generated when, respsectively, the tn3270eRtDataEntry is created and
  deleted.  If, in addition, this tn3270eRtCollCtlType object's
  average(3) bit is set to 1, then the the tn3270eRtExceeded and
  tn3270eRtOkay notifications are generated when the conditions they
  report occur.

  The following notifications are defined by this MIB:

      o tn3270eRtExceeded - The purpose of this notification is to
        signal that a performance problem has been detected. If
        average(3) response time data is being collected, then this
        notification is generated whenever (1) an average response
        time is first found, on a collection interval boundary, to
        have exceeded the high threshold tn3270eRtCollCtlThreshHigh
        specified for the client group, AND (2) the sample on which the
        average is based is determined to have been a significant one,
        via the significance algorithm described earlier. This
        notification is not generated again for a tn3270eRtDataEntry
        until an average response time falling below the low
        threshold tn3270eRtCollCtlThreshLow specified for the client
        group has occured for the entry.

      o tn3270eRtOkay - The purpose of this notification is to signal
        that a previously reported performance problem has been
        resolved. If average(3) response time data is being collected,
        then this notification is generated whenever (1) a
        tn3270eRtExceeded notification has already been generated, AND



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        (2) an average response time is first found, on a collection
        interval boundary, to have fallen below the low threshold
        tn3270eRtCollCtlThreshLow specified for the client group.
        This notification is not generated again for a
        tn3270eRtDataEntry until an average response time
        exceeding the high threshold tn3270eRtCollCtlThreshHigh
        specified for the client group has occurred for the entry.

  Taken together, the two preceding notifications serve to minimize the
  generation of an excessive number of traps in the case of an average
  response time that oscillates about its high threshold.

      o tn3270eRtCollStart - This notification is generated whenever
        data collection begins for a client group, or when a new
        tn3270eRtDataEntry becomes active.  The primary purpose of
        this notification is signal to a management application that
        a new client TCP session has been established, and to provide
        the IP-to-resource mapping for the session. This notification
        is not critical when average(3) data collection is not being
        performed for the client group.

      o tn3270eRtCollEnd - This notification is generated whenever
        a data collection ends. For an aggregate collection, this
        occurs when the corresponding tn3270eRtCollCtlEntry is
        deleted.  For an individual collection, this occurs either
        when the tn3270eRtCollCtlEntry is deleted, or when the
        client's TCP connection terminates.  The purpose of this
        notification is to enable a management application to
        complete a monitoring function that it was performing, by
        returning final values for the collection's data objects.


5.  Definitions

  TN3270E-RT-MIB DEFINITIONS ::= BEGIN

  IMPORTS
      MODULE-IDENTITY, OBJECT-TYPE, NOTIFICATION-TYPE,
      experimental, Counter32, BITS, Unsigned32,
      Gauge32
                  FROM SNMPv2-SMI
      RowStatus, DateAndTime, TimeStamp
                  FROM SNMPv2-TC
      MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
                  FROM SNMPv2-CONF
      Tn3270eAddrType, Tn3270eTAddress, tn3270eSrvrConfIndex,
      tn3270eResMapElementName, tn3270eResMapElementType
                  FROM TN3270E-MIB



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      Utf8String
                  FROM SYSAPPL-MIB;

  tn3270eRtMIB   MODULE-IDENTITY
      LAST-UPDATED "9709240000Z" -- September 24, 1997
      ORGANIZATION "TN3270E Working Group"
      CONTACT-INFO
        "Kenneth White (kennethw@vnet.ibm.com)
         IBM Corp. - Dept. BRQA/Bldg. 503/C117
         P.O. Box 12195
         3039 Cornwallis
         RTP, NC 27709-2195
         (919) 254-0102

         Robert Moore (remoore@us.ibm.com)
         IBM Corp. - Dept. BRQA/Bldg. 501/G114
         P.O. Box 12195
         3039 Cornwallis
         RTP, NC 27709-2195
         (919) 254-7507"
      DESCRIPTION
        "This module defines a portion of the management information
         base (MIB) that enables monitoring of TN3270 and TN3270E
         clients' response times by a TN3270E server."
      ::= { experimental 81 }

  -- Top level structure of the MIB

  tn3270eRtNotifications   OBJECT IDENTIFIER  ::= { tn3270eRtMIB 0 }
  tn3270eRtObjects         OBJECT IDENTIFIER  ::= { tn3270eRtMIB 1 }
  tn3270eRtConformance     OBJECT IDENTIFIER  ::= { tn3270eRtMIB 3 }

  -- MIB Objects

  -- Response Time Control Table

  tn3270eRtCollCtlTable  OBJECT-TYPE
      SYNTAX       SEQUENCE OF Tn3270eRtCollCtlEntry
      MAX-ACCESS   not-accessible
      STATUS       current
      DESCRIPTION
        "The response time monitoring collection control table, which
         allows a management application to control the types of
         response time data being collected, and the clients for which
         it is being collected.

         This table is indexed by tn3270eSrvrConfIndex, imported from
         the TN3270E-MIB, and by tn3270eRtCollCtlClientGroupName.



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         tn3270eSrvrConfIndex indicates within a host which TN3270E
         server an entry applied to.

         tn3270eRtCollCtlClientGroupName is equivalent to the
         tn3270eClientGroupName index in the TN3270E-MIB; it identifies
         the collection of IP clients for which response time data
         is being collectedr. The particular IP clients making up the
         collection are identified in the tn3270eClientGroupTable in
         the TN3270E-MIB."
      ::= { tn3270eRtObjects 1}

  tn3270eRtCollCtlEntry    OBJECT-TYPE
      SYNTAX        Tn3270eRtCollCtlEntry
      MAX-ACCESS    not-accessible
      STATUS        current
      DESCRIPTION
        "Entry in the TN3270E response time monitoring collection
         control table. To handle the case of multiple TN3270E servers
         on the same host, the first index of this table is the
         tn3270eSrvrConfIndex from the TN3270E-MIB."
      INDEX {
        tn3270eSrvrConfIndex,             -- Server's index
        tn3270eRtCollCtlClientGroupName } -- What to collect on
      ::= { tn3270eRtCollCtlTable 1 }

  Tn3270eRtCollCtlEntry ::= SEQUENCE {
      tn3270eRtCollCtlClientGroupName   Utf8String,
      tn3270eRtCollCtlType              BITS,
      tn3270eRtCollCtlSPeriod           Unsigned32,
      tn3270eRtCollCtlSPMult            Unsigned32,
      tn3270eRtCollCtlThreshHigh        Unsigned32,
      tn3270eRtCollCtlThreshLow         Unsigned32,
      tn3270eRtCollCtlIdleRate          Unsigned32,
      tn3270eRtCollCtlBucketBndry1      Unsigned32,
      tn3270eRtCollCtlBucketBndry2      Unsigned32,
      tn3270eRtCollCtlBucketBndry3      Unsigned32,
      tn3270eRtCollCtlBucketBndry4      Unsigned32,
      tn3270eRtCollCtlRowStatus         RowStatus   }

  tn3270eRtCollCtlClientGroupName OBJECT-TYPE
      SYNTAX      Utf8String (SIZE(1..24))
      MAX-ACCESS  not-accessible
      STATUS      current
      DESCRIPTION
          "The name of a client group. Membership in a client group is
           specified via the TN3270E-MIB's tn3270eClientGroupTable.
           The index for that table, tn3270eClientGroupName, is
           equivalent to this object; it was not imported because



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           doing so results in MIB compiler errors."

      ::= { tn3270eRtCollCtlEntry 1 }

  tn3270eRtCollCtlType  OBJECT-TYPE
      SYNTAX    BITS {
                    aggregate(0),
                    excludeIpComponent(1),
                    ddr(2),
                    average(3),
                    buckets(4),
                    traps(5)
                     }
      MAX-ACCESS   read-create
      STATUS       current
      DESCRIPTION
        "This object controls what types of response time data to
         collect, whether to summarize the data across the members
         of a client group or keep it individually, whether to
         introduce dynamic definite responses, and whether to
         generate traps.

         aggregate(0)          - Aggregate response time data for the
                                 client group as a whole. If this bit is
                                 set to 0, then maintain response time
                                 data separately for each member of the
                                 client group.
         excludeIpComponent(1) - Do not include the IP-network component
                                 in any response times.
         ddr(2)                - Enable dynamic definite response.
         average(3)            - Produce an average response time based
                                 on a specified collection interval.
         buckets(4)            - Maintain tn3270eRtDataBucket values in
                                 a corresponding tn3270eRtDataEntry,
                                 based on the bucket boundaries
                                 specified in the
                                 tn3270eRtDataBucketBndry objects.
         traps(5)              - generate the traps specified in this
                                 MIB module. The tn3270eRtExceeded and
                                 tn3270eRtOkay are generated only if
                                 average(3) is also specified."
      ::= { tn3270eRtCollCtlEntry 2 }

  tn3270eRtCollCtlSPeriod OBJECT-TYPE
      SYNTAX  Unsigned32 -- 15 second minimum to 24 hour max
      UNITS   "seconds"
      MAX-ACCESS   read-create
      STATUS       current



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      DESCRIPTION
        "The number of seconds that defines the sample period.
         The actual interval is defined as tn3270eRtCollCtlSPeriod
         times tn3270eRtCollCtlSPMult.

         The value of this object is used only if the corresponding
         tn3270eRtCollCtlType has the average(3) setting."
      DEFVAL   {20}    -- 20 seconds
      ::= { tn3270eRtCollCtlEntry 3 }

  tn3270eRtCollCtlSPMult OBJECT-TYPE
      SYNTAX  Unsigned32 -- should be > 1
      UNITS   "count"
      MAX-ACCESS   read-create
      STATUS       current
      DESCRIPTION
        "The sample period multiplier; this value is multiplied by the
         sample period, tn3270eRtCollCtlSPeriod, to determine the
         collection interval.

         The value of this object is used only if the corresponding
         tn3270eRtCollCtlType has the average(3) setting."
      DEFVAL   { 30 }    -- yields an interval of 10 minutes when
                         -- used with the default SPeriod value
      ::= { tn3270eRtCollCtlEntry 4 }

  tn3270eRtCollCtlThreshHigh  OBJECT-TYPE
      SYNTAX            Unsigned32
      UNITS             "seconds"
      MAX-ACCESS        read-create
      STATUS            current
      DESCRIPTION
        "The threshold for generating a tn3270eRtExceeded notification,
        signalling that a monitored total response time has exceeded the
        specified limit.  A value of zero for this object suppresses
        generation of this notification.  The value of this object is
        used only if the corresponding tn3270eRtCollCtlType has
        average(3) and traps(5) selected."
       ::= { tn3270eRtCollCtlEntry 5 }

  tn3270eRtCollCtlThreshLow   OBJECT-TYPE
      SYNTAX            Unsigned32
      UNITS             "seconds"
      MAX-ACCESS        read-create
      STATUS            current
      DESCRIPTION
        "The threshold for generating a tn3270eRtOkay notification,
        signalling that a monitored total response time has fallen below



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        the specified limit.  A value of zero for this object suppresses
        generation of this notification.  The value of this object is
        used only if the corresponding tn3270eRtCollCtlType has
        average(3) and traps(5) selected."
      ::= { tn3270eRtCollCtlEntry 6 }

  tn3270eRtCollCtlIdleRate   OBJECT-TYPE
      SYNTAX            Unsigned32
      UNITS             "transaction count"
      MAX-ACCESS        read-create
      STATUS            current
      DESCRIPTION
        "The value of this object is used to determine whether a sample
         that yields an average response time exceeding the value of
         tn3270eRtCollCtlThreshHigh was a statistically valid one.  If
         the following statement is true, then the sample was
         statistically valid, and so a tn3270eRtExceeded notification
         should be generated:

            AvgTransCount * ((AvgRt/ThreshHigh - 1) ** 2) <  IdleRate

         This comparison is done only if the corresponding
         tn3270eRtCollCtlType has average(3) and traps(5) selected."
      DEFVAL { 1 }
      ::= { tn3270eRtCollCtlEntry 7 }

  tn3270eRtCollCtlBucketBndry1   OBJECT-TYPE
      SYNTAX            Unsigned32
      UNITS             "tenths of seconds"
      MAX-ACCESS        read-create
      STATUS            current
      DESCRIPTION
        "The value of this object defines the range of transaction
         response times counted in the Tn3270eRtDataBucket1 object:
         those less than or equal to this value."
      DEFVAL { 10 }
      ::= { tn3270eRtCollCtlEntry 8 }

  tn3270eRtCollCtlBucketBndry2   OBJECT-TYPE
      SYNTAX            Unsigned32
      UNITS             "tenths of seconds"
      MAX-ACCESS        read-create
      STATUS            current
      DESCRIPTION
        "The value of this object, together with that of the
        tn3270eRtCollCtlBucketBndry1 object, defines the range of
        transaction response times counted in the Tn3270eRtDataBucket2
        object:  those greater than the value of the



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        tn3270eRtCollCtlBucketBndry1 object, and less than or equal to
        the value of this object."
      DEFVAL { 20 }
      ::= { tn3270eRtCollCtlEntry 9 }

  tn3270eRtCollCtlBucketBndry3   OBJECT-TYPE
      SYNTAX            Unsigned32
      UNITS             "tenths of seconds"
      MAX-ACCESS        read-create
      STATUS            current
      DESCRIPTION
        "The value of this object, together with that of the
        tn3270eRtCollCtlBucketBndry2 object, defines the range of
        transaction response times counted in the Tn3270eRtDataBucket3
        object:  those greater than the value of the
        tn3270eRtCollCtlBucketBndry2 object, and less than or equal to
        the value of this object."
      DEFVAL { 50 }
      ::= { tn3270eRtCollCtlEntry 10 }

  tn3270eRtCollCtlBucketBndry4   OBJECT-TYPE
      SYNTAX            Unsigned32
      UNITS             "tenths of seconds"
      MAX-ACCESS        read-create
      STATUS            current
      DESCRIPTION
        "The value of this object, together with that of the
        tn3270eRtCollCtlBucketBndry3 object, defines the range of
        transaction response times counted in the Tn3270eRtDataBucket4
        object:  those greater than the value of the
        tn3270eRtCollCtlBucketBndry3 object, and less than or equal to
        the value of this object.

        The value of this object also defines the range of transaction
        response times counted in the Tn3270eRtDataBucket5 object:
        those greater than the value of this object."
      DEFVAL { 100 }
      ::= { tn3270eRtCollCtlEntry 11 }

  tn3270eRtCollCtlRowStatus  OBJECT-TYPE
      SYNTAX            RowStatus
      MAX-ACCESS        read-create
      STATUS            current
      DESCRIPTION
        "This object allows entries to be created and deleted
         in the tn3270eRtCollCtlTable.  An entry in this table
         is deleted by setting this object to destroy(6).
         Deleting an entry in this table has the side-effect



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         of removing all entries from the tn3270eRtDataTable
         that are associated with the entry being deleted."
      ::= { tn3270eRtCollCtlEntry 12 }


  -- TN3270E Response Time Data Table

  tn3270eRtDataTable  OBJECT-TYPE
      SYNTAX       SEQUENCE OF Tn3270eRtDataEntry
      MAX-ACCESS   not-accessible
      STATUS       current
      DESCRIPTION
        "The response time data table. Entries in this table are
         created based on entries in the tn3270eRtCollCtlTable."
      ::= { tn3270eRtObjects 2 }

  tn3270eRtDataEntry  OBJECT-TYPE
      SYNTAX        Tn3270eRtDataEntry
      MAX-ACCESS    not-accessible
      STATUS        current
      DESCRIPTION
        "An entry in this table is created based upon the
         tn3270eRtCollCtlTable.  A single entry is created with a
         tn3270eRtDataClientAddrType of 'unknown(0)' and a null octet
         string value for tn3270eRtDataClientAddress when the
         corresponding tn3270eRtCollCtlType has aggregate(0) specified.
         When aggregate(0) is not specified, then a separate entry is
         created for each client.

         Note that the following objects defined within an
         entry in this table can wrap:
            tn3270eRtDataTotalRt
            tn3270eRtDataTotalIpRt
            tn3270eRtDataTransCount
            tn3270eRtDataDrCount
            tn3270eRtDataElapsRnTrpSq
            tn3270eRtDataElapsIpRtSq
            tn3270eRtDataBucket1
            tn3270eRtDataBucket2
            tn3270eRtDataBucket3
            tn3270eRtDataBucket4
            tn3270eRtDataBucket5"
      INDEX {
         tn3270eSrvrConfIndex,            -- Server's local index
         tn3270eRtCollCtlClientGroupName, -- Target of data collection
         tn3270eRtDataClientAddrType,
         tn3270eRtDataClientAddress }
      ::= { tn3270eRtDataTable 1 }



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  Tn3270eRtDataEntry ::= SEQUENCE {
         tn3270eRtDataClientAddrType        Tn3270eAddrType,
         tn3270eRtDataClientAddress         Tn3270eTAddress,
         tn3270eRtDataDiscontinuityTime     TimeStamp,
         tn3270eRtDataAvgRt                 Gauge32,
         tn3270eRtDataAvgIpRt               Gauge32,
         tn3270eRtDataAvgTransCount         Counter32,
         tn3270eRtDataIntTimeStamp          DateAndTime,
         tn3270eRtDataTotalRt               Counter32,
         tn3270eRtDataTotalIpRt             Counter32,
         tn3270eRtDataTransCount            Counter32,
         tn3270eRtDataDrCount               Counter32,
         tn3270eRtDataElapsRndTrpSq         Unsigned32,
         tn3270eRtDataElapsIpRtSq           Unsigned32,
         tn3270eRtDataBucket1               Counter32,
         tn3270eRtDataBucket2               Counter32,
         tn3270eRtDataBucket3               Counter32,
         tn3270eRtDataBucket4               Counter32,
         tn3270eRtDataBucket5               Counter32
     }

  tn3270eRtDataClientAddrType   OBJECT-TYPE
      SYNTAX    Tn3270eAddrType
      MAX-ACCESS   not-accessible
      STATUS       current
      DESCRIPTION
        "Indicates the type of address that following in the
         instance OID represented by tn3270eRtDataClientAddress."
      ::= { tn3270eRtDataEntry 1 }

  tn3270eRtDataClientAddress   OBJECT-TYPE
      SYNTAX    Tn3270eTAddress
      MAX-ACCESS   not-accessible
      STATUS       current
      DESCRIPTION
        "Contains the IP address of the TN3270 client being
         monitored. A null octet string is used if the aggregate
         of the Client Group is being collected "
      ::= { tn3270eRtDataEntry 2 }

  tn3270eRtDataDiscontinuityTime OBJECT-TYPE
      SYNTAX      TimeStamp
      MAX-ACCESS  read-only
      STATUS      current
      DESCRIPTION
          "The value of sysUpTime on the most recent occasion at
           which any one or more of this entry's objects
           suffered a discontinuity. One possibility of this is



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           when a TN3270E Server is stopped and then restarted
           where local methods are used to setup collection
           policy (tn3270eRtCollCtlTable entries).

           In order to prevent a TN3270E Server from caching this
           object it is recommended that the TN3270E Server's
           startup time be used as the objects initial value."
      ::= { tn3270eRtDataEntry 3 }

  tn3270eRtDataAvgRt OBJECT-TYPE
      SYNTAX       Gauge32
      UNITS        "tenths of seconds"
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "The average total response time measured over the last
         collection interval."
      DEFVAL { 0 }
      ::= { tn3270eRtDataEntry 4 }

  tn3270eRtDataAvgIpRt OBJECT-TYPE
      SYNTAX       Gauge32
      UNITS        "tenths of seconds"
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "The average IP response time measured over the last
         collection interval."
      DEFVAL { 0 }
      ::= { tn3270eRtDataEntry 5 }

  tn3270eRtDataAvgTransCount   OBJECT-TYPE
      SYNTAX       Counter32
      UNITS        "transactions"
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "The sliding transaction count used for calculating the values
         of the tn3270eRtDataAvgRt and tn3270eRtDataAvgIpRt objects.
         The actual transaction count is available in the
         tn3270eRtDataTransCount object."
      ::= { tn3270eRtDataEntry 6 }

  tn3270eRtDataIntTimeStamp   OBJECT-TYPE
      SYNTAX       DateAndTime
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION



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        "The date and time of the last interval that tn3270eRtDataAvgRt,
         tn3270eRtDataAvgIpRt, and tn3270eRtDataAvgTransCount were
         calculated."
      ::= { tn3270eRtDataEntry 7 }

  tn3270eRtDataTotalRt   OBJECT-TYPE
      SYNTAX       Counter32
      UNITS        "tenths of seconds"
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "A count of the total response time collected."
      ::= { tn3270eRtDataEntry 8 }

  tn3270eRtDataTotalIpRt   OBJECT-TYPE
      SYNTAX       Counter32
      UNITS        "tenths of seconds"
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "A count of the total IP-network response time collected."
      ::= { tn3270eRtDataEntry 9 }

  tn3270eRtDataTransCount   OBJECT-TYPE
      SYNTAX       Counter32
      UNITS        "transactions"
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "A count of the total number of transactions detected."
      ::= { tn3270eRtDataEntry 10 }

  tn3270eRtDataDrCount   OBJECT-TYPE
      SYNTAX       Counter32
      UNITS        "transactions"
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "A count of the total number of definite responses detected."
      ::= { tn3270eRtDataEntry 11 }

  tn3270eRtDataElapsRndTrpSq   OBJECT-TYPE
      SYNTAX       Unsigned32
      UNITS        "tenths of seconds squared"
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "The sum of the elapsed round trip time squared.  A sum of the



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         squares is keep in order to calculate a variance."
      DEFVAL { 0 }
      ::= { tn3270eRtDataEntry 12 }

  tn3270eRtDataElapsIpRtSq   OBJECT-TYPE
      SYNTAX       Unsigned32
      UNITS        "tenths of seconds squared"
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "The sum of the elapsed IP round trip time squared.  A sum of
         the squares is keep in order to calculate a variance."
      DEFVAL { 0 }
      ::= { tn3270eRtDataEntry 13 }

  tn3270eRtDataBucket1   OBJECT-TYPE
      SYNTAX       Counter32
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "A count of the response times falling into bucket 1."
      ::= { tn3270eRtDataEntry 14 }

  tn3270eRtDataBucket2   OBJECT-TYPE
      SYNTAX       Counter32
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "A count of the response times falling into bucket 2."
      ::= { tn3270eRtDataEntry 15 }

  tn3270eRtDataBucket3   OBJECT-TYPE
      SYNTAX       Counter32
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "A count of the response times falling into bucket 3."
      ::= { tn3270eRtDataEntry 16 }

  tn3270eRtDataBucket4  OBJECT-TYPE
      SYNTAX       Counter32
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
         "A count of the response times falling into bucket 4."
      ::= { tn3270eRtDataEntry 17 }

  tn3270eRtDataBucket5  OBJECT-TYPE



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      SYNTAX       Counter32
      MAX-ACCESS   read-only
      STATUS       current
      DESCRIPTION
        "A count of the response times falling into bucket 5."
      ::= { tn3270eRtDataEntry 18 }

  -- Notifications

  tn3270eRtExceeded   NOTIFICATION-TYPE
      OBJECTS {
         tn3270eSrvrConfIndex,            -- server's local index
         tn3270eRtCollCtlClientGroupName, -- target of data collection
         tn3270eRtDataClientAddrType,
         tn3270eRtDataClientAddress,
         tn3270eRtDataIntTimeStamp,
         tn3270eRtDataAvgRt,
         tn3270eRtDataAvgIpRt,
         tn3270eRtDataAvgTransCount
      }
      STATUS  current
      DESCRIPTION
        "This notification is generated when the average response time,
        tn3270eRtDataAvgRt, exceeds tn3270eRtCollCtlThresholdHigh at
        the end of a collection interval specified by
        tn3270eCollCtlSPeriod times tn3270eCollCtlSPMult.  Note that
        the corresponding tn3270eCollCtlType must have traps(5) and
        average(3) set for this notification to be generated.  In
        addition, tn3270eRtDataAvgTransCount,
        tn3270eRtCollCtlThreshHigh and tn3270eRtDataAvgRt are
        algorithmically compared to tn3270eRtCollCtlIdleRate for
        determination if this will be suppressed."
      ::= { tn3270eRtNotifications 1 }

  tn3270eRtOkay   NOTIFICATION-TYPE
      OBJECTS {
         tn3270eSrvrConfIndex,            -- server's local index
         tn3270eRtCollCtlClientGroupName, -- target of data collection
         tn3270eRtDataClientAddrType,
         tn3270eRtDataClientAddress,-- IP Address or null octet string
         tn3270eRtDataIntTimeStamp,
         tn3270eRtDataAvgRt,
         tn3270eRtDataAvgIpRt,
         tn3270eRtDataAvgTransCount
      }
      STATUS  current
      DESCRIPTION
        "This notification is generated when the average response time,



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        tn3270eRtDataAvgRt, falls below tn3270eRtCollCtlThresholdLow at
        the end of a collection interval specified by
        tn3270eCollCtlSPeriod times tn3270eCollCtlSPMult, after a
        tn3270eRtExceeded notification was generated.  Note that the
        corresponding tn3270eCollCtlType must have traps(5) and
        average(3) set for this notification to be generated."
      ::= { tn3270eRtNotifications 2 }

  tn3270eRtCollStart NOTIFICATION-TYPE
      OBJECTS {
         tn3270eSrvrConfIndex,        -- server's local index
         tn3270eRtCollCtlClientGroupName, -- Data collection target
         tn3270eRtDataClientAddrType,
         tn3270eRtDataClientAddress,  -- IP Address or null octet string
         tn3270eResMapElementName,    -- IDs LU or printer association
         tn3270eResMapElementType     -- type of resource
      }
      STATUS  current
      DESCRIPTION
        "This notification is generated when response time data
        collection is enabled for a member of a client group.  In order
        for this notification to occur the corresponding
        tn3270eRtCollCtlType must have traps(5) selected.  The objects
        tn3270eResMapElementName and tn3270eResMapElementType contains
        valid values only if tn3270eRtDataClientAddress contains a
        valid IP address (rather than the null octet string)."
      ::= { tn3270eRtNotifications 3 }

  tn3270eRtCollEnd   NOTIFICATION-TYPE
      OBJECTS {
         tn3270eSrvrConfIndex,            -- server's local index
         tn3270eRtCollCtlClientGroupName, -- data collection target
         tn3270eRtDataClientAddrType,
         tn3270eRtDataClientAddress,
         tn3270eRtDataDiscontinuityTime,
         tn3270eRtDataAvgRt,
         tn3270eRtDataAvgIpRt,
         tn3270eRtDataAvgTransCount,
         tn3270eRtDataIntTimeStamp,
         tn3270eRtDataTotalRt,
         tn3270eRtDataTotalIpRt,
         tn3270eRtDataTransCount,
         tn3270eRtDataDrCount,
         tn3270eRtDataElapsRndTrpSq,
         tn3270eRtDataElapsIpRtSq,
         tn3270eRtDataBucket1,
         tn3270eRtDataBucket2,
         tn3270eRtDataBucket3,



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         tn3270eRtDataBucket4,
         tn3270eRtDataBucket5
      }
      STATUS  current
      DESCRIPTION
        "This notification is generated when a tn3270eRtDataEntry is
        deleted after being active (actual data collected), in order to
        enable a management application monitoring a tn3270eRtDataTable
        entry to end get the entry's final values.  Note that the
        corresponding tn3270eCollCtlType must have traps(5) set for this
        notification to be generated."
      ::= { tn3270eRtNotifications 4 }

  -- Conformance Statement

  tn3270eRtGroups       OBJECT IDENTIFIER ::= { tn3270eRtConformance 1 }
  tn3270eRtCompliances  OBJECT IDENTIFIER ::= { tn3270eRtConformance 2 }

  -- Compliance statements

  tn3270eRtCompliance     MODULE-COMPLIANCE
      STATUS current
      DESCRIPTION
        "The compliance statement for agents that support the
         TN327E-RT-MIB "
      MODULE   -- this module
         MANDATORY-GROUPS { tn3270eRtGroup, tn3270eRtNotGroup }
      OBJECT tn3270eRtCollCtlSPeriod
         MIN-ACCESS  read-only
         DESCRIPTION
            "The agent is not required to allow the user to change
             the default value of this object and is allowed
             to use a different default."
      ::= {tn3270eRtCompliances 1 }

  -- Group definitions

  tn3270eRtGroup         OBJECT-GROUP
      OBJECTS {
          tn3270eRtCollCtlType,
          tn3270eRtCollCtlSPeriod,
          tn3270eRtCollCtlSPMult,
          tn3270eRtCollCtlThreshHigh,
          tn3270eRtCollCtlThreshLow,
          tn3270eRtCollCtlIdleRate,
          tn3270eRtCollCtlBucketBndry1,
          tn3270eRtCollCtlBucketBndry2,
          tn3270eRtCollCtlBucketBndry3,



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          tn3270eRtCollCtlBucketBndry4,
          tn3270eRtCollCtlRowStatus,
          tn3270eRtDataDiscontinuityTime,
          tn3270eRtDataAvgRt,
          tn3270eRtDataAvgIpRt,
          tn3270eRtDataAvgTransCount,
          tn3270eRtDataIntTimeStamp,
          tn3270eRtDataTotalRt,
          tn3270eRtDataTotalIpRt,
          tn3270eRtDataTransCount,
          tn3270eRtDataDrCount,
          tn3270eRtDataElapsRndTrpSq,
          tn3270eRtDataElapsIpRtSq,
          tn3270eRtDataBucket1,
          tn3270eRtDataBucket2,
          tn3270eRtDataBucket3,
          tn3270eRtDataBucket4,
          tn3270eRtDataBucket5 }
      STATUS  current
      DESCRIPTION
        "This group is mandatory for all host supporting the
         TN3270E-RT-MIB. "
      ::= { tn3270eRtGroups 1 }

  tn3270eRtNotGroup         NOTIFICATION-GROUP
      NOTIFICATIONS {
          tn3270eRtExceeded,
          tn3270eRtOkay,
          tn3270eRtCollStart,
          tn3270eRtCollEnd
       }
      STATUS  current
      DESCRIPTION
        "The notifications which must be supported when the
         TN3270E-RT-MIB is implemented. "
      ::= { tn3270eRtGroups 2 }

  END


6.  Security Considerations

  Certain management information defined in this MIB may be considered
  sensitive in some network environments.  Therefore, authentication of
  received SNMP requests and controlled access to management information
  should be employed in such environments.  The method for this
  authentication is a function of the SNMP Administrative Framework, and
  has not been expanded by this MIB.



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  Several objects in this MIB allow write access or provide for remote
  creation. Allowing this support in a non-secure environment can have a
  negative effect on network operations.  It is recommended that
  implementers seriously consider whether set operations should be
  allowed without providing, at a minimum, authentication of request
  origin. It it recommended that without such support that the following
  objects be implemented as read-only:

      o tn3270eRtCollCtlType
      o tn3270eRtCollSPeriod
      o tn3270eRtCollSPMult
      o tn3270eRtCollCtlThreshHigh
      o tn3270eRtCollCtlThreshLow
      o tn3270eRtCollCtlIdleRate
      o tn3270eRtCollCtlBucketBndry1
      o tn3270eRtCollCtlBucketBndry2
      o tn3270eRtCollCtlBucketBndry3
      o tn3270eRtCollCtlBucketBndry4

  The following object should either be implemented as read-only or not
  implemented when security is an issue as previously discussed:

      o tn3270eRtCollCtlRowStatus

  The administrative method to use to create and manage the
  tn3270eRtCollCtlTable when SET support is not allowed is outside of
  the scope of this memo.


7.  Acknowledgments

  This document is a product of the TN3270E Working Group. Special
  thanks is due to Derek Bolton and Michael Boe of Cisco Systems for
  their numerous comments and suggestions for improving the structure of
  this MIB.


8.  References


[1]  SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and
     Waldbusser S., "Structure of Management Information for version 2
     of the Simple Network Management Protocol (SNMPv2)", RFC 1902,
     January 1996.


[2]  Network Working Group, Postel, J., and Reynolds, J., "Telnet
     Protocol Specification", RFC 854, May 1983.



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[3]  Network Working Group, Postel, J., and Reynolds, J., "Telnet Timing
     Mark Option", RFC 860, May 1983.


[4]  Network Working Group and Rekhter J., "Telnet 3270 Regime Option",
     RFC 1041, January 1988.


[5]  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.


[6]  SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S.
     Waldbusser, "Textual Conventions for version 2 of the Simple
     Network Management Protocol (SNMPv2)", RFC 1903, January 1996.


[7]  SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S.
     Waldbusser, "Protocol Operations for version 2 of the Simple
     Network Management Protocol (SNMPv2)", RFC 1905, January 1996.


[8]  SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S.
     Waldbusser, "Conformance Statements for version 2 of the Simple
     Network Management Protocol (SNMPv2)", RFC 1904, January 1996.


[9]  Case, J., M. Fedor, M. Schoffstall, J. Davin, "Simple Network
     Management Protocol", RFC 1157, SNMP Research, Performance Systems
     International, MIT Laboratory for Computer Science, May 1990.


[10] IETF TN3270E Working Group and White, K., "Base Definitions of
     Managed Objects for TN3270E Using SMIv2", Internet-Draft Work in
     progress, June 1997.


[11] Network Working Group, and Kelly, B., "TN3270 Enhancements", RFC
     1647, July 1994.


[12] IBM, International Technical Support Centers, "Response Time Data
     Gathering", GG24-3212-01, November 1990.


[13] Krupczak, Cheryl, Saperia, Jonathan, "Definitions of System-Level



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     Managed Objects for Applications", April 15, 1997.


9.  Authors' Addresses

  Kenneth D. White
  Dept. BRQA/Bldg. 503/C117
  IBM Corporation
  P.O.Box 12195
  3039 Cornwallis
  Research Triangle Park, NC 27709, USA
  Phone: +1-919-254-0102
  E-mail: kennethw@vnet.ibm.com

  Robert Moore
  Dept. BRQA/Bldg. 501/G114
  IBM Corporation
  P.O.Box 12195
  3039 Cornwallis
  Research Triangle Park, NC 27709, USA
  Phone: +1-919-254-7507
  E-mail: remoore@us.ibm.com





























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