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RFC 3202

Proposed STD
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Definitions of Managed Objects for Frame Relay Service Level Definitions

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Network Working Group                                     R. Steinberger
Request for Comments: 3202                             Paradyne Networks
Category: Standards Track                                    O. Nicklass
                                            RAD Data Communications Ltd.
                                                            January 2002


                     Definitions of Managed Objects
               for Frame Relay Service Level Definitions

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This memo defines an extension of the Management Information Base
   (MIB) for use with network management protocols in TCP/IP-based
   internets.  In particular, it defines objects for managing the Frame
   Relay Service Level Definitions.

Table of Contents

   1. The SNMP Management Framework ...............................    2
   2. Conventions .................................................    3
   3. Overview ....................................................    3
   3.1. Frame Relay Service Level Definitions .....................    4
   3.2. Terminology ...............................................    5
   3.3. Network Model .............................................    5
   3.4. Reference Points ..........................................    6
   3.5. Measurement Methodology ...................................    8
   3.6. Theory of Operation .......................................    9
   3.6.1. Capabilities Discovery ..................................    9
   3.6.2. Determining Reference Points for Row Creation ...........   10
   3.6.2.1. Graphical Examples of Reference Points ................   11
   3.6.2.1.1. Edge-to-Edge Interface Reference Point Example ......   12
   3.6.2.1.2. Edge-to-Edge Egress Queue Reference Point Example ...   13
   3.6.2.1.3. End-to-End Using Reference Point Example ............   14
   3.6.3. Creation Process ........................................   15
   3.6.4. Destruction Process .....................................   15

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   3.6.4.1. Manual Row Destruction ................................   15
   3.6.4.2. Automatic Row Destruction .............................   16
   3.6.5. Modification Process ....................................   16
   3.6.6. Collection Process ......................................   16
   3.6.6.1. Remote Polling ........................................   16
   3.6.6.2. Sampling ..............................................   17
   3.6.6.3. User History ..........................................   17
   3.6.7. Use of MIB Module in Calculation of Service Level
   Definitions ....................................................   17
   3.6.8. Delay ...................................................   20
   3.6.9. Frame Delivery Ratio ....................................   20
   3.6.10. Data Delivery Ratio ....................................   21
   3.6.11. Service Availability ...................................   21
   4. Relation to Other MIB Modules ...............................   22
   5. Structure of the MIB Module .................................   23
   5.1. frsldPvcCtrlTable .........................................   23
   5.2. frsldSmplCtrlTable ........................................   23
   5.3. frsldPvcDataTable .........................................   23
   5.4. frsldPvcSampleTable .......................................   24
   5.5. frsldCapabilities .........................................   24
   6. Persistence of Data .........................................   24
   7. Object Definitions ..........................................   24
   8. Acknowledgments .............................................   61
   9. References ..................................................   61
   10. Security Considerations ....................................   63
   11. Authors' Addresses .........................................   63
   12. Full Copyright Statement ...................................   64

1.  The SNMP Management Framework

   The SNMP Management Framework presently consists of five major
   components:

   o  An overall architecture, described in RFC 2571 [1].

   o  Mechanisms for describing and naming objects and events for the
      purpose of management.  The first version of this Structure of
      Management Information (SMI) is called SMIv1 and described in STD
      16, RFC 1155 [2], STD 16, RFC 1212 [3] and RFC 1215 [4].  The
      second version, called SMIv2, is described in STD 58, RFC 2578
      [5], RFC 2579 [6] and RFC 2580 [7].

   o  Message protocols for transferring management information.  The
      first version of the SNMP message protocol is called SNMPv1 and
      described in STD 15, RFC 1157 [8].  A second version of the SNMP
      message protocol, which is not an Internet standards track
      protocol, is called SNMPv2c and described in RFC 1901 [9] and RFC

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      1906 [10].  The third version of the message protocol is called
      SNMPv3 and described in RFC 1906 [10], RFC 2572 [11] and RFC 2574
      [12].

   o  Protocol operations for accessing management information.  The
      first set of protocol operations and associated PDU formats is
      described in STD 15, RFC 1157 [8].  A second set of protocol
      operations and associated PDU formats is described in RFC 1905
      [13].

   o  A set of fundamental applications described in RFC 2573 [14] and
      the view-based access control mechanism described in RFC 2575
      [15].

   A more detailed introduction to the current SNMP Management Framework
   can be found in RFC 2570 [16].

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the mechanisms defined in the SMI.

   This memo specifies a MIB module that is compliant to the SMIv2.  A
   MIB conforming to the SMIv1 can be produced through the appropriate
   translations.  The resulting translated MIB must be semantically
   equivalent, except where objects or events are omitted because no
   translation is possible (use of Counter64).  Some machine readable
   information in SMIv2 will be converted into textual descriptions in
   SMIv1 during the translation process.  However, this loss of machine
   readable information is not considered to change the semantics of the
   MIB.

2.  Conventions

   The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
   SHOULD NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when
   they appear in this document, are to be interpreted as described in
   RFC 2119 [22].

3.  Overview

   This MIB module addresses the items required to manage the Frame
   Relay Forum's Implementation Agreement for Service Level Definitions
   (FRF.13 [17]).  At present, this applies to these values of the
   ifType variable in the Internet-standard MIB:

   o  frameRelay (32)

   o  frameRelayService (44)

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   This section provides an overview and background of how to use this
   MIB module.

3.1.  Frame Relay Service Level Definitions

   The frame relay service level definitions address specific
   characteristics of a frame relay service that can be used to
   facilitate the following tasks:

   o  Evaluation of frame relay service providers, offerings or
      products.

   o  Measurement of Quality of Service.

   o  Enforcement of Service Level Agreements.

   o  Planning or describing a frame relay network.

   The following parameters are defined in FRF.13 [17] as a sufficient
   set of values to accomplish the tasks previously stated.

   o  Delay - The amount of time elapsed, in microseconds, from the time
      a frame exits the source to the time it reaches the destination.
      NOTE: FRF.13 [17] defines this value in terms of milliseconds.

   o  Frame Delivery Ratio - The ratio of the number of frames delivered
      to the destination versus the number of frames sent by the source.
      This ratio can be further divided by inspecting either only the
      frames within the CIR or only the frames in excess of the CIR.

   o  Data Delivery Ratio - The ratio of the amount of data delivered to
      the destination versus the amount of data sent by the source.
      This ratio can be further divided by inspecting either only the
      data within the CIR or only the data in excess of the CIR.

   o  Service Availability - The amount of time the frame relay service
      was not available.  There are three types of availability
      statistics defined in FRF.13 [17]: Mean Time to Repair, Virtual
      Connection Availability, and Mean Time Between Service Outages.
      The later two require information about the scheduled outage time.
      It is assumed that scheduled outage time information will be
      maintained by the network management software, so it is not
      included in the MIB module.

   Consult FRF.13 [17] for more details.

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3.2.  Terminology

   o  CIR - The Committed Information Rate (CIR) is the subscriber data
      rate (expressed in bits/second) that the network commits to
      deliver under normal network conditions [18].

   o  DLCI - Data Link Connection Identifier [18].

   o  Logical Port - This term is used to model the Frame Relay
      "interface" on a device [18].

   o  NNI - Network to Network Interface [18].

   o  Permanent Virtual Connection (PVC) - A virtual connection that has
      its end-points and bearer capabilities defined at subscription
      time [18].

   o  Reference Point (RP) - The point of reference within the network
      model at which the calculations or data collection takes place.

   o  UNI - User to Network Interface [18].

3.3.  Network Model

   The basic model, as illustrated in figure 1 below, contains two frame
   relay DTE endpoints connected to a network cloud via a frame relay
   UNI interface.  The network cloud can contain zero or more internal
   frame relay NNI connections that interconnect multiple networks.  The
   calculations and data collection can be performed at any reference
   point within the network.

   +-------------+                                       +-------------+
   | Frame Relay |                                       | Frame Relay |
   | DTE Device  |                                       | DTE Device  |
   +------+------+                                       +------+------+
          |                                                     |
         UNI                                                   UNI
      Connection                                            Connection
          |                                                     |
   +------+------+    NNI     +-------------+    NNI     +------+------+
   |  Network A  +------------+  Network B  +------------+  Network C  |
   +-------------+ Connection +-------------+ Connection +-------------+

                                 Figure 1
                    Frame Relay Network Reference Model

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3.4.  Reference Points

   The collection and calculations of the service level definitions
   apply to two reference points within the network.  These two points
   are the locations where the frames are referenced in the collection
   of the service level specific information.  The reference points used
   in the MIB module are shown in figure 2 below.  For completeness, the
   module also allows for proprietary reference points which MAY exist
   anywhere in the network that is not a previously defined reference
   point.  The meaning of the proprietary reference points is
   insignificant unless defined by the device manufacturer.

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      +---------------------------+
      |+-----------+ +-----------+|
      ||           | |Measurement||
      ||Frame Relay---Engine     --(Source RP)----+
      ||DTE        | |(If Exists)||               |
      |+-----------+ +-----------+|               |
      +---------------------------+               |
        Frame Relay Source                        |
       +------------------------------------------+
       |             Frame Relay Network
       |            +----------------------------------+
       |            | +------------------------------+ |
       |            | | +---------+ +---------+      | |
       |            | | |         | | Traffic |      | |
       +--(Ingress RP)--- L1 / L2 --- Policing|      | |
                    | | | Control | | Engine  |      | |
                    | | +---------+ +----|----+      | |
                    | |                  |           | |
                    | |         (Traffic Policing RP)| |
                    | +------------------|-----------+ |
                    |    Ingress Node    |             |
                    |                    |             |
                    |        +-----------|-----------+ |
                    |        |  Intermediate Nodes   | |
                    |        +-----------|-----------+ |
                    |                    |             |
                    |      Egress Node   |             |
                    |     +--------------|-----------+ |
                    |     | (Egress Queue Input RP)  | |
                    |     |              |           | |
                    |     |      +-------+------+    | |
                    |     |      | Egress Queue |    | |
                    |     |      +-------+------+    | |
                    |     |              |           | |
                    |     | (Egress Queue Output RP) | |
                    |     +--------------|-----------+ |
                    +--------------------|-------------+
         Frame Relay Destination         |
      +---------------------------+      +-----------+
      |+-----------+ +-----------+|                  |
      ||           | |Measurement||                  |
      ||Frame Relay---Engine     --(Destination RP)--+
      ||DTE        | |(If Exists)||
      |+-----------+ +-----------+|
      +---------------------------+

                                Figure 2
                     Reference Points (FRF.13 [17])

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   The MIB variables frsldPvcCtrlTransmitRP and frsldPvcCtrlReceiveRP
   allow the user to view and configure the reference points at which
   the calculations occur.  These variables are specific to the device
   on which they are located.  Frame relay devices act as both frame
   sources and frame destinations.  The definitions in this MIB module
   apply to the interaction of a pair of devices on the network path.
   The same device can potentially use different reference points for
   calculation and collection of the statistics based on whether the
   referenced frame is sent or received by the device.  When the device
   is acting as a frame source, the value of frsldPvcCtrlTransmitRP
   reflects the reference point used for all source calculations
   pertaining to the specified PVC.  When the device is acting as a
   frame destination, the value of frsldPvcCtrlReceiveRP reflects the
   reference point used for all destination calculations pertaining to
   the specified PVC.

   For example, FRF.13 [17] defines an Edge-to-Edge Egress Queue
   measurement domain as a domain in which measurement is performed
   between an Ingress Reference Point and an Egress Queue Input
   Reference Point.  For this domain between a source device and a
   destination device, the value of frsldPvcCtrlTransmitRP for the
   source device would be set to ingTxLocalRP(2) and the value of
   frsldPvcCtrlReceiveRP for the destination device would be set to
   eqiRxLocalRP(4).  While it is usually the case that the reference
   points would be equivalent on the remote device when monitoring
   frames going in the opposite direction, there is no requirement for
   them to be so.

   It can be seen from the above example that a total of four reference
   points are required in order to collect information for both
   directions of traffic flow.  The reference points represent the
   transmit and receive directions at both ends of a PVC.  If a device
   has knowledge of the information from the remote device, it is
   possible to collect the statistics from a single device.  This is not
   always the case.  In most instances, two devices will need to be
   monitored to capture a complete description of the service level on a
   PVC.  The reference points a single device is capable of monitoring
   are contained in the frsldRPCaps object.

3.5.  Measurement Methodology

   This document neither recommends nor suggests a method of
   implementation.  This is left to the device manufacturer and should
   be independent of the data that is actually collected.

   Periodic collection of this data can be performed through either
   polling of the data table, use of the sample tables or use of the
   user history group of RFC 2021 [19].

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3.6.  Theory of Operation

   The following sections describe how to use this MIB module.  They
   include row handling, data collection and data calculation.  The
   recommendations here in are suggestions as to implementation and do
   not infer that they are the only method that can be used to perform
   such operations.

3.6.1.  Capabilities Discovery

   Three objects are provided specifically to aid the network manager in
   discovering the capabilities of the device with respect to this MIB
   module.

   o  frsldPvcCtrlWriteCaps  This object reports the write capabilities
                             of the PVC Control Table.  Use this object
                             to determine which objects can be modified.
                             This need only be referenced if row
                             creation or modification is to be
                             performed.

   o  frsldSmplCtrlWriteCaps This object reports the write capabilities
                             of the Sample Control Table.  Use this
                             object to determine which objects can be
                             modified.  The group need only be
                             referenced if the sample tables will be
                             used to collect historical information.

   o  frsldRPCaps            This object reports the reference points at
                             which the device is capable of collecting
                             information.  This object needs to be
                             referenced if row creation is to be
                             performed in the PVC Control Table.
                             Devices can only create rows containing
                             supported reference points.

   These objects do not imply that there is no need for an Agent
   Capabilities macro for devices that do not fully support every object
   in this MIB module.  They are provided specifically to aid in the
   ensured network management operations of this MIB module with respect
   to row creation and modification.

   An additional four objects are provided to report and control memory
   the utilization of this MIB module.  These objects are
   frsldMaxPvcCtrls, frsldNumPvcCtrls, frsldMaxSmplCtrls are
   frsldNumSmplCtrls.  Together, they allow a manager to control the

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   amount of memory allocated for specific utilization by this MIB
   module.  This is done by setting the maximum allowed allocation of
   controls.

3.6.2.  Determining Reference Points for Row Creation

   The performance of a PVC is monitored by evaluating the uni-
   directional flow of frames from an ingress point to an egress point.
   Reference points describe where each of the two measurements are
   made.  Monitoring both of the uni-directional flows that make-up the
   PVC frame traffic requires a total of four reference points as shown
   in Figures 3 through 5.  A monitoring point that evaluates traffic is
   restricted to counting frames that pass the reference points hosted
   locally on the monitoring point.  Thus, if the monitoring point is
   near the ingress point of the flow, it will count the frames entering
   into the frame relay network.  The complete picture of frame loss for
   the uni-directional flow requires information from the downstream
   reference point located at another (remote) monitoring point.

   The local monitoring point MAY be implemented in such way that the
   information from the downstream monitoring point is moved to the
   local monitoring point using implementation-specific mechanisms.  In
   this case all information required to calculate frame loss becomes
   available from the local measurement point.  The local measurement
   point agent is capable of reporting all the objects in the
   FrsldPvcDataEntry row - the counts for offered frames entering the
   network and delivered frames exiting the network.

   Alternatively, the local monitoring point MAY be restricted to counts
   of frames observed on the local device only.  In this case, the
   objects of the FrsldPvcDataEntry row reporting what happened on the
   remote device are not available.

   The following list shows the possible valid reference points for an
   FRF.13 SLA from the source reference point to the destination
   reference point in both directions.

   o  Local Information Only

         Local Device:  srcLocalRP, desLocalRP
         Remote Device: srcLocalRP, desLocalRP

   o  Remote Information Only

         Local Device:  srcRemoteRP, desRemoteRP
         Remote Device: srcRemoteRP, desRemoteRP

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   o  Mixed Two Device Model 1 (Local Device Always Transmitter)

         Local Device:  srcLocalRP, desRemoteRP
         Remote Device: srcLocalRP, desRemoteRP

   o  Mixed Two Device Model 2 (Local Device Always Receiver)

         Local Device:  srcRemoteRP, desLocalRP
         Remote Device: srcRemoteRP, desLocalRP

   o  Mixed One Device Model 1 (Directional Rows)

         First Row:  srcRemoteRP, desLocalRP (Receiver Row)
         Second Row: srcLocalRP, desRemoteRP (Sender Row)

   o  Mixed One Device Model 2 (Device Based Rows)

         First Row:  srcLocalRP, desLocalRP (Local Row)
         Second Row: srcRemoteRP, desRemoteRP (Remote Row)

   Each of the above combinations is valid and provides the same
   information.

   The following steps are recommended to find which reference points
   need to be configured:

   1) Locate both of the devices at either end of the PVC to be
      monitored.

   2) Determine the capabilities by referencing the frsldRPCaps object
      of each device.

   3) Locate the best combination of the two devices such that the
      necessary reference points are all represented.

   4) If any one of the necessary reference points does not exist in the
      combination of the two devices, it is not possible to monitor the
      FRF.13 defined SLA between the two reference point on the PVC.

3.6.2.1.  Graphical Examples of Reference Points

   FRF.13 [17] defines three specific combinations of reference points:
   Edge-to-Edge Interface, Edge-to-Edge Egress Queue and End-to-End.

   Examples of valid reference points that may be used for each of these
   are discussed in the sections below.

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   It is often the case that a device knows as a minimum either only
   local information or both local and remote information.  Because
   these are two common examples, each will be illustrated below.

3.6.2.1.1.  Edge-to-Edge Interface Reference Point Example

            Device 1                               Device 2
         +-------------+                        +-------------+
         |   Ingress   |                        |   Egress    |
         |   +-----+   |                        |   +-----+   |
         |(A)|     |   |      Traffic Flow      |   |     |(B)|
      -->-->--     -->-->-->-->-->-->-->-->-->-->-->-     -->-->-->
         |   |     |   |   From Device 1 to 2   |   |     |   |
         |   +-----+   |                        |   +-----+   |
         |             |                        |             |
         |   Egress    |                        |   Ingress   |
         |   +-----+   |                        |   +-----+   |
         |(D)|     |   |      Traffic Flow      |   |     |(C)|
      <--<--<-     -<--<--<--<--<--<--<--<--<--<--<--     --<--<--
         |   |     |   |   From Device 2 to 1   |   |     |   |
         |   +-----+   |                        |   +-----+   |
         +-------------+                        +-------------+

            where (A), (B), (C) and (D) are reference points

                                Figure 3

   For devices with only local knowledge, one row is required on each
   device as follows:

   (A) frsldPvcCtrlTransmitRP for Device 1 = ingTxLocalRP(2)

   (B) frsldPvcCtlrReceiveRP for Device 2 = eqoRxLocalRP(5)

   (C) frsldPvcCtrlTransmitRP for Device 2 = ingTxLocalRP(2)

   (D) frsldPvcCtlrReceiveRP for Device 1 = eqoRxLocalRP(5)

   In which a single row is created on Device 1 containing reference
   points (A) and (D), and a single row is created on Device 2
   containing reference points (C) and (B).

   For devices with both local and remote knowledge, the two rows can
   exist in any combination on either device.  For this example, the
   transmitting devices will be responsible for information regarding
   the flow for which they are the origin.  Only one row is required per
   device for this example.

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   (A) frsldPvcCtrlTransmitRP for Device 1 = ingTxLocalRP(2)

   (B) frsldPvcCtlrReceiveRP for Device 1 = eqoRxRemoteRP(11)

   (C) frsldPvcCtrlTransmitRP for Device 2 = ingTxLocalRP(2)

   (D) frsldPvcCtlrReceiveRP for Device 2 = eqoRxRemoteRP(11)

3.6.2.1.2.  Edge-to-Edge Egress Queue Reference Point Example

            Device 1                               Device 2
         +-------------+                        +-------------+
         |   Ingress   |                        |   Egress    |
         |   +-----+   |                        |   +-----+   |
         |(A)|     |   |      Traffic Flow      |(B)|     |   |
      -->-->--     -->-->-->-->-->-->-->-->-->-->-->-     -->-->-->
         |   |     |   |   From Device 1 to 2   |   |     |   |
         |   +-----+   |                        |   +-----+   |
         |             |                        |             |
         |   Egress    |                        |   Ingress   |
         |   +-----+   |                        |   +-----+   |
         |   |     |(D)|      Traffic Flow      |   |     |(C)|
      <--<--<-     -<--<--<--<--<--<--<--<--<--<--<--     --<--<--
         |   |     |   |   From Device 2 to 1   |   |     |   |
         |   +-----+   |                        |   +-----+   |
         +-------------+                        +-------------+

            where (A), (B), (C) and (D) are reference points

                                Figure 4

   For devices with only local knowledge, one row is required on each
   device as follows:

   (A) frsldPvcCtrlTransmitRP for Device 1 = ingTxLocalRP(2)

   (B) frsldPvcCtlrReceiveRP for Device 2 = eqiRxLocalRP(4)

   (C) frsldPvcCtrlTransmitRP for Device 2 = ingTxLocalRP(2)

   (D) frsldPvcCtlrReceiveRP for Device 1 = eqiRxLocalRP(4)

   In which a single row is created on Device 1 containing reference
   points (A) and (D), and a single row is created on Device 2
   containing reference points (C) and (B).

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   For devices with both local and remote knowledge, the two rows can
   exist in any combination on either device.  For this example, the
   transmitting devices will be responsible for information regarding
   the flow for which they are the origin.  Only one row is required per
   device for this example.

   (A) frsldPvcCtrlTransmitRP for Device 1 = ingTxLocalRP(2)

   (B) frsldPvcCtlrReceiveRP for Device 1 = eqiRxRemoteRP(10)

   (C) frsldPvcCtrlTransmitRP for Device 2 = ingTxLocalRP(2)

   (D) frsldPvcCtlrReceiveRP for Device 2 = eqiRxRemoteRP(10)

3.6.2.1.3.  End-to-End Using Reference Point Example

            Device 1                               Device 2
         +-------------+                        +-------------+
         |   Source    |                        | Destination |
         |   +-----+   |                        |   +-----+   |
         |(A)|     |   |      Traffic Flow      |   |     |(B)|
      -->-->--     -->-->-->-->-->-->-->-->-->-->-->-     -->-->-->
         |   |     |   |   From Device 1 to 2   |   |     |   |
         |   +-----+   |                        |   +-----+   |
         |             |                        |             |
         | Destination |                        |   Source    |
         |   +-----+   |                        |   +-----+   |
         |(D)|     |   |      Traffic Flow      |   |     |(C)|
      <--<--<-     -<--<--<--<--<--<--<--<--<--<--<--     --<--<--
         |   |     |   |   From Device 2 to 1   |   |     |   |
         |   +-----+   |                        |   +-----+   |
         +-------------+                        +-------------+

            where (A), (B), (C) and (D) are reference points

                                Figure 5

   For devices with only local knowledge, one row is required on each
   device as follows:

   (A) frsldPvcCtrlTransmitRP for Device 1 = srcLocalRP(1)

   (B) frsldPvcCtlrReceiveRP for Device 2 = desLocalRP(1)

   (C) frsldPvcCtrlTransmitRP for Device 2 = srcLocalRP(1)

   (D) frsldPvcCtlrReceiveRP for Device 1 = desLocalRP(1)

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   In which a single row is created on Device 1 containing reference
   points (A) and (D), and a single row is created on Device 2
   containing reference points (C) and (B).

   For devices with both local and remote knowledge, the two rows can
   exist in any combination on either device.  For this example, the
   transmitting devices will be responsible for information regarding
   the flow for which they are the origin.  Only one row is required per
   device for this example.

   (A) frsldPvcCtrlTransmitRP for Device 1 = srcLocalRP(1)

   (B) frsldPvcCtlrReceiveRP for Device 1 = desRemoteRP(7)

   (C) frsldPvcCtrlTransmitRP for Device 2 = srcLocalRP(1)

   (D) frsldPvcCtlrReceiveRP for Device 2 = desRemoteRP(7)

3.6.3.  Creation Process

   In some cases, devices will automatically populate the rows of PVC
   Control Table and potentially the Sample Control Table.  However, in
   many cases, it may be necessary for a network manager to manually
   create rows.

   Manual creation of rows requires the following steps:

   1) Ensure the PVC exists between the two devices.

   2) Determine the necessary reference points for row creation.

   3) Create the row(s) in each device as needed.

   4) Create the row(s) in the sample control tables if desired.

3.6.4.  Destruction Process

3.6.4.1.  Manual Row Destruction

   Manual row destruction is straight forward.  Any row can be destroyed
   and the resources allocated to it are freed by setting the value of
   its status object (either frsldPvcCtrlStatus or frsldSmplCtrlStatus)
   to destroy(6).  It should be noted that when frsldPvcCtrlStatus is
   set to destroy(6) all associated sample control, sample and data
   table rows will also be destroyed.  Similarly, when
   frsldSmplCtrlStatus is set to destroy(6) all sample rows will also be

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   destroyed.  The frsldPvcCtrlPurge objects do not apply to manual row
   destruction.  If the row is set to destroy(6) manually, the rows are
   destroyed as part of the set.

3.6.4.2.  Automatic Row Destruction

   Rows is the tables may be destroyed automatically based on the
   existence of the DLCI on which they rely.  This behavior is
   controlled by the frsldPvcCtrlPurge and frsldPvcCtrlDeleteOnPurge
   objects.  When a DLCI no longer exists in the device, the data in the
   tables has no relation to anything known on the network.  However,
   there may be some need to keep the historic information active for a
   short period after the destruction or removal of a DLCI.  If the
   basis for the row no longer exists, the row will be destroyed at the
   end of the purge interval that is controlled by frsldPvcCtrlPurge.

   The effects of automatic row destruction are the same as manual row
   destruction.

3.6.5.  Modification Process

   All read-create items in this MIB module can be modified at any time
   if they are fully supported.  Write access is not required.  To
   simplify the use of the MIB frsldPvcCtrlWriteCaps and
   frsldSmplCtrlWriteCaps state which of the read-create variables can
   actually be written on a particular device.

3.6.6.  Collection Process

3.6.6.1.  Remote Polling

   This MIB module supports data collection through remote polling of
   the free running counters in the PVC Data Table.  Remote polling is a
   common method used to capture real-time statistics.  A remote
   management station polls the device to collect the desired
   information.  It is recommended all statistics for a single PVC be
   collected in a single PDU.

   The following objects are designed around the concept of real-time
   polling:

   o  frsldPvcDataMissedPolls
   o  frsldPvcDataFrDeliveredC
   o  frsldPvcDataFrDeliveredE
   o  frsldPvcDataFrOfferedC
   o  frsldPvcDataFrOfferedE
   o  frsldPvcDataDataDeliveredC
   o  frsldPvcDataDataDeliveredE

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   o  frsldPvcDataDataOfferedC
   o  frsldPvcDataDataOfferedE
   o  frsldPvcDataHCFrDeliveredC
   o  frsldPvcDataHCFrDeliveredE
   o  frsldPvcDataHCFrOfferedC
   o  frsldPvcDataHCFrOfferedE
   o  frsldPvcDataHCDataDeliveredC
   o  frsldPvcDataHCDataDeliveredE
   o  frsldPvcDataHCDataOfferedC
   o  frsldPvcDataHCDataOfferedE
   o  frsldPvcDataUnavailableTime
   o  frsldPvcDataUnavailables

3.6.6.2.  Sampling

   The sample tables provide the ability to historically sample data
   without requiring the additional overhead of polling.  At key
   periods, a network management station can collect the samples needed.
   This method allows the manager to perform the collection of data at
   times that will least affect the active network traffic.

   The sample data can be collected using a series of SNMP getNext or
   getBulk operations.  The value of frsldPvcSmplIdx increments with
   each new collection bucket.  This allows the managers to skip
   information that has already been collected.  However, care should be
   taken in that the value can roll over after a long period of time.

   The start and end times of a collection period allow the manager to
   know what the actual period of collection was.  It is possible for
   there to be discontinuities in the sample table, so both start and
   end should be referenced.

3.6.6.3.  User History

   User history, as defined in RFC 2021 [19], is an alternative
   mechanism that can be used to get the same benefits as the sample
   table by using the objects provided for real-time polling.  Some
   devices MAY have the ability to use user history and opt not to
   support the sample tables.  If this is the case, the information from
   the data table can be used to define a group of user history objects.

3.6.7.  Use of MIB Module in Calculation of Service Level Definitions

   The objects in this MIB module can be used to calculate the
   statistics defined in FRF.13 [17].  The description below describes
   the calculations for one direction of the data flow, i.e., data sent
   from local transmitter to a remote receiver.  A complete set of
   bidirectional information would require calculations based on both

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   directions.  For the purposes of this description, the reference
   points used SHOULD consistently represent data that is sent by one
   device and received by the other.

   A complete evaluation requires the combination of two uni-directional
   flows.  It is possible for a management station to combine all of the
   calculated information into one conceptual row.  Doing this requires
   that each of the metrics are collected for both flow directions and
   grouped by direction  If the information is split between two
   devices, the management station must know which two devices to
   communicate with for the collection of all information.  The grouping
   of information SHOULD be from ingress to egress in each flow
   direction.

   The calculations below use the following terminology:

   o  DelayAvg

         The average delay on the PVC.  This is represented within the
         MIB module by frsldPvcSmplDelayAvg.

   o  FrDeliveredC

         The number of frames received by the receiving device through
         the receive reference point that were delivered within CIR.
         This is represented within the MIB module by one of
         frsldPvcDataFrDeliveredC, frsldPvcDataHCFrDeliveredC,
         frsldPvcSmplFrDeliveredC, or frsldPvcSmplHCFrDeliveredC.

   o  FrDeliveredE

         The number of frames received by the receiving device through
         the receive reference point that were delivered in excess of
         CIR.  This is represented within the MIB module by one of
         frsldPvcDataFrDeliveredE, frsldPvcDataHCFrDeliveredE,
         frsldPvcSmplFrDeliveredE, or frsldPvcSmplHCFrDeliveredE.

   o  FrOfferedC

         The number of frames offered by the transmitting device through
         the transmit reference point that were sent within CIR.  This
         is represented within the MIB module by one of
         frsldPvcDataFrOfferedC, frsldPvcDataHCFrOfferedC,
         frsldPvcSmplFrOfferedC, or frsldPvcSmplHCFrOfferedC.

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   o  FrOfferedE

         The number of frames offered by the transmitting device through
         the transmit reference point that were sent in excess of CIR.
         This is represented within the MIB module by one of
         frsldPvcDataFrOfferedE, frsldPvcDataHCFrOfferedE,
         frsldPvcSmplFrOfferedE, or frsldPvcSmplHCFrOfferedE.

   o  DataDeliveredC

         The number of octets received by the receiving device through
         the receive reference point that were delivered within CIR.
         This is represented within the MIB module by one of
         frsldPvcDataDataDeliveredC, frsldPvcDataHCDataDeliveredC,
         frsldPvcSmplDataDeliveredC, or frsldPvcSmplHCDataDeliveredC.

   o  DataDeliveredE

         The number of octets received by the receiving device through
         the receive reference point that were delivered in excess of
         CIR.  This is represented within the MIB module by one of
         frsldPvcDataDataDeliveredE, frsldPvcDataHCDataDeliveredE,
         frsldPvcSmplDataDeliveredE, or frsldPvcSmplHCDataDeliveredE.

   o  DataOfferedC

         The number of octets offered by the transmitting device through
         the transmit reference point that were sent within CIR.  This
         is represented within the MIB module by one of
         frsldPvcDataDataOfferedC, frsldPvcDataHCDataOfferedC,
         frsldPvcSmplDataOfferedC, or frsldPvcSmplHCDataOfferedC.

   o  DataOfferedE

         The number of octets offered by the transmitting device through
         the transmit reference point that were sent in excess of CIR.
         This is represented within the MIB module by one of
         frsldPvcDataDataOfferedE, frsldPvcDataHCDataOfferedE,
         frsldPvcSmplDataOfferedE, or frsldPvcSmplHCDataOfferedE.

   o  UnavailableTime

         The amount of time the PVC was not available during the
         interval of interest.  This is represented within the MIB
         module by either frsldPvcDataUnavailableTime or
         frsldPvcSmplUnavailableTime.

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   o  Unavailables

         The number of times the PVC was declared to be unavailable
         during the interval of interest.  This is represented within
         the MIB module by either frsldPvcDataUnavailables or
         frsldPvcSmplUnavailables.

3.6.8.  Delay

   The frame transfer delay is defined as the amount of time elapsed, in
   microseconds, from the time a frame exits the source to the time it
   reaches the destination.  The average delay can be found using the
   MIB variable described in DelayAvg above.  The delay may be
   calculated as either round trip or one way, and this information is
   held in the frsldPvcCtrlDelayType MIB variable.  If the delay be
   calculated as round trip, the value of DelayAvg represents the
   average of the total delays of the round trips.  In this case, the
   manager SHOULD divide the value returned by the agent by two to
   obtain the frame transfer delay.  In the case that
   frsldPvcCtrlDelayType is oneWay, the value of DelayAvg represents the
   average of the frame transfer delays and SHOULD be used as is.

3.6.9.  Frame Delivery Ratio

   The frame delivery ratio is defined as the total number of frames
   delivered to the destination divided by the frames offered by the
   source.  The destination values can be obtained using FrDeliveredC
   and FrDeliveredE.  The source values can be obtained using FrOfferedC
   and FrOfferedE.

                          FrDeliveredC + FrDeliveredE
   Frame Delivery Ratio = ---------------------------
                            FrOfferedC + FrOfferedE

                                     FrDeliveredC
   Committed Frame Delivery Ratio =  ------------
                                      FrOfferedC

                                  FrDeliveredE
   Excess Frame Delivery Ratio =  ------------
                                   FrOfferedE

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3.6.10.  Data Delivery Ratio

   The data delivery ratio is defined as the total amount of data
   delivered to the destination divided by the data offered by the
   source.  The destination values can be obtained using DataDeliveredC
   and DataDeliveredE.  The source values can be obtained using
   DataOfferedC and DataOfferedE.

                         DataDeliveredC + DataDeliveredE
   Data Delivery Ratio = -------------------------------
                           DataOfferedC + DataOfferedE

                                   DataDeliveredC
   Committed Data Delivery Ratio = --------------
                                    DataOfferedC

                                DataDeliveredE
   Excess Data Delivery Ratio = --------------
                                 DataOfferedE

3.6.11.  Service Availability

   Some forms of service availability measurement defined in FRF.13 [17]
   require knowledge of the amount of time the network is allowed to be
   unavailable during the period of measurement.  This is called the
   excluded outage time and will be represented in the measurements
   below as ExcludedTime.  It is assumed that the management software
   will maintain this information in that it often relates to specific
   times and dates that many devices are not capable of maintaining.
   Further, it may change based on a moving maintenance window that the
   device cannot track well.

   Mean Time to Repair (FRMTTR) = 0 if Unavailables is 0.

                       UnavailableTime
   Otherwise, FRMTTR = ---------------
                        Unavailables


   Virtual Connection Availability (FRVCA) = 0 if IntervalTime equals
                                                  ExcludedTime.

                      IntervalTime - ExcludedTime - UnavailableTime
   Otherwise, FRVCA = --------------------------------------------- *100
                               IntervalTime - ExcludedTime


   Mean Time Between Service Outages (FRMTBSO) = 0 if Unavailables is 0.

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   Otherwise, FRMTBSO = IntervalTime - ExcludedTime - UnavailableTime
                        ---------------------------------------------
                                       Unavailables

4.  Relation to Other MIB Modules

   There is no explicit relation to any other frame relay MIB module nor
   are any required to implement this MIB module.  However, there is a
   need for knowledge of ifIndexes and some understanding of DLCIs.  The
   ifIndex information can be found in the IF-MIB [21] which is
   required.  The DLCI information can be found in either the Frame
   Relay DTE MIB (RFC 2115) [20] or the Frame Relay Network Services MIB
   (RFC 2954) [18]; however, neither is required.

   Upon setting of frsldPvcCtrlStatus in the frsldPvcCtrlTable to
   active(1) the system can be in one of the following three states:

   (1) The respective DLCI is known and is active.  This corresponds to
       a state in which frPVCEndptRowStatus is active(1) and
       frPVCEndptRcvdSigStatus is either active(2) or none(4) for the
       Frame Relay Network Services MIB (RFC 2954) [18].  For the Frame
       Relay DTE MIB, the same state is shown by frCircuitRowStatus of
       active(1) and  frCircuitState of active(2).

   (2) The respective DLCI has not been created.  This corresponds to a
       state in which the row with either frPVCEndptDLCIIndex or
       frCircuitDlci equal to the respective DLCI does not exist in
       either the frPVCEndptTable or the frCircuitTable respectively.

   (3) The respective DLCI has just been removed.  This corresponds to a
       state in which either frPVCEndptRowStatus is no longer active(1)
       or frPVCEndptRcvdSigStatus is no longer active(2) or none(4) for
       the Frame Relay Network Services MIB (RFC 2954) [18].  For the
       Frame Relay DTE MIB, the same state is shown when either
       frCircuitRowStatus is no longer active(1) or frCircuitState is no
       longer active(2).

   For the first case, the row in the frsldPvcDataTable will be filled.
   If frsldSmplCtrlStatus in the frsldSmplCtrlTable for the respective
   DLCI is also `active' the frsldPvcSampleTable will be filled as well.

   For the second case, the respective rows will not be added to any of
   the data or sample tables and frsldPvcCtrlStatus SHOULD report
   notReady(3).

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   For the third case, frsldPvcCtrlDeleteOnPurge should direct the
   behavior of the system.  If all tables are purged, this case will be
   equivalent to the second case above.  Otherwise, frsldPvcCtrlStatus
   SHOULD remain active(1).

5.  Structure of the MIB Module

   The FRSLD-MIB consists of the following components:

   o  frsldPvcCtrlTable

   o  frsldSmplCtrlTable

   o  frsldPvcDataTable

   o  frsldPvcSampleTable

   o  frsldCapabilities

   Refer to the compliance statement defined within for a definition of
   what objects MUST be implemented.

5.1.  frsldPvcCtrlTable

   The frsldPvcCtrlTable is the central control table for operations of
   the Frame Relay Service Level Definitions MIB.  It provides variables
   to control the parameters required to calculate the objects in the
   other tables.

   A row in this table MUST exist in order for a row to exist in any
   other table in this MIB module.

5.2.  frsldSmplCtrlTable

   This is an optional table to allow control of sampling of the data in
   the data table.

5.3.  frsldPvcDataTable

   This table contains the calculated data.  It relies on configuration
   from the control table.

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5.4.  frsldPvcSampleTable

   This table contains samples of the delivery and availability
   information from the data table as well as delay information
   calculated over the sample period.  It relies on configuration from
   both the control table and the sample control table.

5.5.  frsldCapabilities

   This is a group of objects that define write capabilities of the
   read-create objects in the tables above.

6.  Persistence of Data

   The data in frsldPvcCtrlTable and frsldSmplCtrlTable SHOULD persist
   through power cycles.  Note, however, that the symantics of readiness
   for the rows still applies.  This means that it is possible for a row
   to be reprovisioned as notReady(3) if the underlying DLCI does not
   persist.  The data collected in the other tables SHOULD NOT persist
   through power cycles in that the reference TimeStamp is no longer
   valid.



(page 24 continued on part 2)

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