rfc2214.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

           Should  the sum of the different elements delay
           exceed (2**32)-1, the end-to-end  delay  should
           be (2**32)-1."
       ::= { intSrvGuaranteedIfEntry 2 }

    intSrvGuaranteedIfSlack OBJECT-TYPE
        SYNTAX      INTEGER (0..'0FFFFFFF'h)
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "If a network element uses a certain amount  of
           slack,  Si,  to  reduce the amount of resources
           that it has reserved for a particular flow,  i,
           the  value  Si  should be stored at the network
           element.   Subsequently,  if  reservation   re-
           freshes  are  received  for flow i, the network
           element must use the same slack Si without  any
           further computation. This guarantees consisten-
           cy in the reservation process.

           As an example for the use of  the  slack  term,
           consider the case where the required end-to-end
           delay, Dreq, is larger than the  maximum  delay
           of the fluid flow system.  In this, Ctot is the



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           sum of the Backlog terms end to end,  and  Dtot
           is the sum of the delay terms end to end.  Dreq
           is obtained by setting R=r in the  fluid  delay
           formula, and is given by

                        b/r + Ctot/r + Dtot.

           In this case the slack term is

                  S = Dreq - (b/r + Ctot/r + Dtot).

           The slack term may be used by the network  ele-
           ments  to  adjust  their local reservations, so
           that they can admit flows that would  otherwise
           have been rejected. A service element at an in-
           termediate network element that can  internally
           differentiate between delay and rate guarantees
           can now take advantage of this  information  to
           lower the amount of resources allocated to this
           flow. For example, by taking an amount of slack
           s  <= S, an RCSD scheduler [5] can increase the
           local delay bound, d, assigned to the flow,  to
           d+s. Given an RSpec, (Rin, Sin), it would do so
           by setting Rout = Rin and Sout = Sin - s.

           Similarly,  a  network  element  using  a   WFQ
           scheduler  can  decrease  its local reservation
           from Rin to Rout by using some of the slack  in
           the  RSpec.  This  can be accomplished by using
           the transformation rules given in the  previous
           section,  that ensure that the reduced reserva-
           tion level will not increase the  overall  end-
           to-end delay."
       ::= { intSrvGuaranteedIfEntry 3 }


    intSrvGuaranteedIfStatus OBJECT-TYPE
        SYNTAX      RowStatus
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "'valid' on interfaces that are configured  for
           the Guaranteed Service."
       ::= { intSrvGuaranteedIfEntry 4 }

--      No notifications are currently defined

-- conformance information



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intSrvGuaranteedGroups      OBJECT IDENTIFIER
                            ::= { intSrvGuaranteedConformance 1 }
intSrvGuaranteedCompliances OBJECT IDENTIFIER
                            ::= { intSrvGuaranteedConformance 2 }

-- compliance statements

    intSrvGuaranteedCompliance MODULE-COMPLIANCE
        STATUS  current
        DESCRIPTION
           "The compliance statement "
       MODULE  -- this module
       MANDATORY-GROUPS {
           intSrvGuaranteedIfAttribGroup
           }
       ::= { intSrvGuaranteedCompliances 1 }


    intSrvGuaranteedIfAttribGroup OBJECT-GROUP
         OBJECTS {
            intSrvGuaranteedIfBacklog,
            intSrvGuaranteedIfDelay,
            intSrvGuaranteedIfSlack,
            intSrvGuaranteedIfStatus
        }
        STATUS  current
        DESCRIPTION
           "These objects are required  for  Systems  sup-
           porting the Guaranteed Service of the Integrat-
           ed Services Architecture."
       ::= { intSrvGuaranteedGroups 2 }

END

4.  Security Considerations

   The use of an SNMP SET results in an RSVP or Integrated Services
   reservation under rules that are different compared to if the
   reservation was negotiated using RSVP. However, no other security
   considerations exist other than those imposed by SNMP itself.











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5.  Authors' Addresses

         Fred Baker
 Postal: Cisco Systems
         519 Lado Drive
         Santa Barbara, California 93111

 Phone:  [phone]
 EMail:  [e-mail]


         John Krawczyk
 Postal: ArrowPoint Communications
         235 Littleton Road
         Westford, Massachusetts 01886

 Phone:  [phone]
 EMail:  [e-mail]


         Arun Sastry
 Postal: Cisco Systems
         210 W. Tasman Drive
         San Jose, California 95314

 Phone:  [phone]
 EMail:  [e-mail]

6.  Acknowledgements

   This document was produced by the Integrated Services Working Group.

7.  References

   [1]  Rose, M., Editor, "Management Information Base for
        Network Management of TCP/IP-based internets", STD 17, RFC 1213,
        May 1990.

   [2]  Information processing systems - Open Systems
        Interconnection - Specification of Abstract Syntax Notation One
        (ASN.1), International Organization for Standardization.
        International Standard 8824, (December, 1987).

   [3]  Information processing systems - Open Systems
        Interconnection - Specification of Basic Encoding Rules for
        Abstract Notation One (ASN.1), International Organization for
        Standardization.  International Standard 8825, (December, 1987).




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