rfc2954.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

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RFC 2954                Frame Relay Service MIB             October 2000


   Be - The Excess Burst Size (Be) is the maximum amount of subscriber
   data (expressed in bits) in excess of Bc that the network will
   attempt to deliver during the time interval Tc.  This data (Be) is
   delivered in general with a lower probability than Bc.

   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.  CIR is averaged over the time
   interval Tc (CIR = Bc/Tc).

   DLCI - Data Link Connection Identifier

   Logical Port - This term is used to model the frame relay "interface"
   on a device.

   NNI - Network to Network Interface

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

   Time slot (E1) - An octet within the 256-bit information field in
   each E1 frame is defined as a time slot.  Time slots are position
   sensitive within the 256-bit information field.  Fractional E1 service
   is provided in contiguous or non-contiguous time slot increments.

   Time slot (DS0) - An octet within the 192-bit information field in
   each DS1 frame is defined as a time slot.  Time slots are position
   sensitive within the 192-bit information field. Fractional DS1
   service is provided in contiguous or non-contiguous time slot
   increments.

   UNI - User to Network Interface

   N391 - Full status (status of all PVCs) polling counter

   N392 - Error threshold

   N393 - Monitored events count

   T391 - Link integrity verification polling timer

   T392 - Polling verification timer

   nT3 - Status enquiry timer

   nN3 - Maximum status enquiry counter





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RFC 2954                Frame Relay Service MIB             October 2000


2.5.  Relation to Other MIBs

2.5.1.  System Group

   Use the System Group of the SNMPv2-MIB [27] to describe the Frame
   Relay Service (FRS) agent.  The FRS agent may be monitoring many
   frame relay devices in one network.  The System Group does not
   describe frame relay devices monitored by the FRS agent.

   sysDescr:  ASCII string describing the FRS agent.
              Can be up to 255 characters long. This field is
              generally used to indicate the network providers
              identification and type of service offered.

   sysObjectID:  Unique OBJECT IDENTIFIER (OID) for the
                 FRS agent.

   sysUpTime:  Clock in the FRS agent; TimeTicks
               in 1/100s of a second.  Elapsed type since
               the FRS agent came on line.

   sysContact:  Contact for the FRS agent.
                ASCII string of up to 255 characters.

   sysName:  Domain name of the FRS agent, for example,
             acme.com

   sysLocation:  Location of the FRS agent.
                 ASCII string of up to 255 characters.

   sysServices:  Services of the managed device.  The value "2",
                 which implies that
                 the frame relay network is providing
                 a subnetwork level service, is recommended.

2.5.2.  Interfaces Table (ifTable, ifXtable)

   This specifies how the Interfaces Group defined in the IF MIB [26]
   shall be used for the management of frame relay based interfaces, and
   in conjunction with the Frame Relay Service MIB module.  This memo
   assumes the interpretation of the evolution of the Interfaces group
   to be in accordance with: "The interfaces table (ifTable) contains
   information on the managed resource's interfaces.  Each sub-layer
   below the internetwork layer of a network interface is considered an
   interface."  Thus, the ifTable allows the following frame relay-based
   interfaces to be represented as table entries:





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RFC 2954                Frame Relay Service MIB             October 2000


   -  Frame relay interfaces in equipment (e.g., switches, routers or
      networks) supporting frame relay.  This level is concerned with
      generic frame counts and not with individual virtual connections.

   In accordance with the guidelines of ifTable, frame counts per
   virtual connection are not covered by ifTable, and are considered
   interface specific and covered in the Frame Relay Service MIB module.
   In order to interrelate the ifEntries properly, the Interfaces Stack
   Group shall be supported.

   Some specific interpretations of ifTable for frame relay follow.

   Object                 Use for the generic Frame Relay layer
   ======                 =============================================
   ifIndex                Each frame relay port is represented by an
                          ifEntry.

   ifDescr                Description of the frame relay interface.
                          ASCII string describing the UNI/NNI logical
                          port.  Can be up to 255 characters long.

   ifType                 The value allocated for Frame Relay Service
                          is equal to 44.

   ifMtu                  Set to maximum frame size in octets for this
                          frame relay logical port.

   ifSpeed                Peak bandwidth in bits per second available
                          for use. This could be the speed of the
                          logical port and not the access rate. Actual
                          user information transfer rate (i.e., access
                          rate) of the UNI or NNI logical port in bits
                          per second (this is not the clocking speed).
                          For example, it is 1,536,000 bits per second
                          for a DS1-based UNI/NNI logical port and
                          1,984,000 bits per second for an E1-based
                          UNI/NNI logical port.

   ifPhysAddress          The primary address for this logical port
                          assigned by the frame relay interface
                          provider.  An octet string of zero length if
                          no address is used for this logical port.

   ifAdminStatus          The desired administrative status of the
                          frame relay logical port.






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RFC 2954                Frame Relay Service MIB             October 2000


   ifOperStatus           The current operational status of the Frame
                          Relay UNI or NNI logical port.

   ifLastChange           The value of sysUptime at the last
                          re-initialization of the logical port.  The
                          value of sysUpTime at the time the logical
                          port entered its current operational state.
                          If the current state was entered prior to the
                          last re-initialization of the local network
                          management subsystem, then this object
                          contains a zero value.

   ifInOctets             The number of received octets.  This counter
                          only counts octets from the beginning of the
                          frame relay header field to the end of user
                          data.

   ifInUcastPkts          The number of received unerrored, unicast
                          frames.

   ifInDiscards           The number of received frames discarded.
                          Specifically, frames discarded due to ingress
                          buffer congestion and traffic policing.

   ifInErrors             The number of received frames that are
                          discarded because of an error. Specifically,
                          frames that are too long or too short, frames
                          that are not a multiple of 8 bits in length,
                          frames with an invalid or unrecognized DLCI,
                          frames with an abort sequence, frames with
                          improper flag delimitation, and frame that
                          fail FCS.

   ifInUnknownProtos      The number of packets discarded because of an
                          unknown or unsupported protocol.  For Frame
                          Relay Service interfaces, this counter will
                          always be zero.

   ifOutOctets            The number of transmitted octets.  This
                          counter only counts octets from the beginning
                          of the frame relay header field to the end of
                          user data.

   ifOutUcastpkts         The number of unerrored, unicast frames sent.

   ifOutDiscards          The number of frames discarded in the egress
                          direction. Possible reasons are as follows:
                          policing, congestion.



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RFC 2954                Frame Relay Service MIB             October 2000


   ifOutErrors            The number of frames discarded in the egress
                          direction because of an error. Specifically,
                          frames that are aborted due to a transmitter
                          underrun.

   ifName                 This variable is not applicable for Frame
                          Relay Service interfaces, therefore, this
                          variable contains a zero-length string.

   ifInMulticastPkts      The number of received unerrored, multicast
                          frames.

   ifInBroadcastPkts      This variable is not applicable for Frame
                          Relay Service interfaces, therefore, this
                          counter is always zero.

   ifOutMulticastPkts     The number of sent unerrored, multicast
                          frames.

   ifOutBroadcastPkts     This variable is not applicable for Frame
                          Relay Service interfaces, therefore, this
                          counter is always zero.

   ifHCInOctets           Only used for DS3-based (and greater) Frame
                          Relay logical ports.  The number of received
                          octets.  This counter only counts octets
                          from the beginning of the frame relay header
                          field to the end of user data.

   ifHCOutOctets          Only used for DS3-based (and greater) Frame
                          Relay logical ports.  The number of
                          transmitted octets.  This counter only counts
                          octets from the beginning of the frame relay
                          header field to the end of user data.

   ifLinkUpDownTrapEnable Set to true(1).  It is recommended that the
                          underlying physical layer notifications be
                          disabled since both are not required.
                          Notifications are enabled at the frame relay
                          service layer specifically because PVC
                          notifications are not to be sent if the frame
                          relay interface fails. Without a
                          linkUp/linkDown notification, the management
                          station would receive no notification of the
                          failure.






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RFC 2954                Frame Relay Service MIB             October 2000


   ifHighSpeed            Set to the user data rate of the frame relay
                          logical port in millions of bits per second.
                          If the user data rate is less than 1 Mbps,
                          then this value is zero.

   ifPromiscuousMode      Set to false(2).

   ifConnectorPresent     Set to false(2).

   Frame relay network service interfaces support the Interface Stack
   Group.  Frame relay network service interfaces do not support any
   other groups or objects in the Interfaces group of the IF MIB.

2.5.3.  Stack Table for DS1/E1 Environment

   This section describes by example how to use ifStackTable to
   represent the relationship of frame relay service to ds0 and
   ds0Bundles with ds1 interfaces [20].

   Example: A frame relay service is being carried on 4 ds0s of a ds1.

     +---------------------+
     | Frame Relay Service |
     +---------------------+
                |
     +---------------------+
     | ds0Bundle           |
     +---------------------+
       |     |     |     |
     +---+ +---+ +---+ +---+
     |ds0| |ds0| |ds0| |ds0|
     +---+ +---+ +---+ +---+
       |     |     |     |
     +---------------------+
     | ds1                 |
     +---------------------+

   The assignment of the index values could for example be:

        ifIndex  Description
        1        FrameRelayService (type 44)
        2        ds0Bundle         (type 82)
        3        ds0 #1            (type 81)
        4        ds0 #2            (type 81)
        5        ds0 #3            (type 81)
        6        ds0 #4            (type 81)
        7        ds1               (type 18)