219 lines
8.5 KiB
Plaintext
219 lines
8.5 KiB
Plaintext
INTEGRATED-SERVICES-GUARANTEED-MIB DEFINITIONS ::= BEGIN
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IMPORTS
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MODULE-IDENTITY, OBJECT-TYPE FROM SNMPv2-SMI
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RowStatus FROM SNMPv2-TC
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MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF
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intSrv FROM INTEGRATED-SERVICES-MIB
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ifIndex FROM IF-MIB;
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-- This MIB module uses the extended OBJECT-TYPE macro as
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-- defined in [9].
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intSrvGuaranteed MODULE-IDENTITY
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LAST-UPDATED "9511030500Z" -- Thu Aug 28 09:04:22 PDT 1997
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ORGANIZATION "IETF Integrated Services Working Group"
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CONTACT-INFO
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" Fred Baker
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Postal: Cisco Systems
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519 Lado Drive
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Santa Barbara, California 93111
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Tel: +1 805 681 0115
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E-Mail: fred@cisco.com"
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DESCRIPTION
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"The MIB module to describe the Guaranteed Service of
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the Integrated Services Protocol"
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::= { intSrv 5 }
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intSrvGuaranteedObjects OBJECT IDENTIFIER
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::= { intSrvGuaranteed 1 }
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intSrvGuaranteedNotifications OBJECT IDENTIFIER
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::= { intSrvGuaranteed 2 }
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intSrvGuaranteedConformance OBJECT IDENTIFIER
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::= { intSrvGuaranteed 3 }
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-- The Integrated Services Interface Attributes Database
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-- contains information that is shared with other reservation
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-- procedures such as ST-II.
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intSrvGuaranteedIfTable OBJECT-TYPE
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SYNTAX SEQUENCE OF IntSrvGuaranteedIfEntry
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MAX-ACCESS not-accessible
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STATUS current
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DESCRIPTION
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"The attributes of the system's interfaces ex-
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ported by the Guaranteed Service."
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::= { intSrvGuaranteedObjects 1 }
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intSrvGuaranteedIfEntry OBJECT-TYPE
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SYNTAX IntSrvGuaranteedIfEntry
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MAX-ACCESS not-accessible
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STATUS current
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DESCRIPTION
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"The reservable attributes of a given inter-
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face."
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INDEX { ifIndex }
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::= { intSrvGuaranteedIfTable 1 }
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IntSrvGuaranteedIfEntry ::=
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SEQUENCE {
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intSrvGuaranteedIfBacklog INTEGER,
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intSrvGuaranteedIfDelay INTEGER,
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intSrvGuaranteedIfSlack INTEGER,
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intSrvGuaranteedIfStatus RowStatus
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}
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intSrvGuaranteedIfBacklog OBJECT-TYPE
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SYNTAX INTEGER (0..'0FFFFFFF'h)
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UNITS "bytes"
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MAX-ACCESS read-create
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STATUS current
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DESCRIPTION
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"The Backlog parameter is the data backlog
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resulting from the vagaries of how a specific
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implementation deviates from a strict bit-by-
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bit service. So, for instance, for packetized
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weighted fair queueing, Backlog is set to the
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Maximum Packet Size.
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The Backlog term is measured in units of bytes.
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An individual element can advertise a Backlog
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value between 1 and 2**28 (a little over 250
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megabytes) and the total added over all ele-
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ments can range as high as (2**32)-1. Should
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the sum of the different elements delay exceed
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(2**32)-1, the end-to-end error term should be
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(2**32)-1."
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::= { intSrvGuaranteedIfEntry 1 }
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intSrvGuaranteedIfDelay OBJECT-TYPE
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SYNTAX INTEGER (0..'0FFFFFFF'h)
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UNITS "microseconds"
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MAX-ACCESS read-create
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STATUS current
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DESCRIPTION
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"The Delay parameter at each service element
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should be set to the maximum packet transfer
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delay (independent of bucket size) through the
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service element. For instance, in a simple
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router, one might compute the worst case amount
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of time it make take for a datagram to get
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through the input interface to the processor,
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and how long it would take to get from the pro-
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cessor to the outbound interface (assuming the
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queueing schemes work correctly). For an Eth-
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ernet, it might represent the worst case delay
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if the maximum number of collisions is experi-
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enced.
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The Delay term is measured in units of one mi-
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crosecond. An individual element can advertise
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a delay value between 1 and 2**28 (somewhat
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over two minutes) and the total delay added all
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elements can range as high as (2**32)-1.
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Should the sum of the different elements delay
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exceed (2**32)-1, the end-to-end delay should
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be (2**32)-1."
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::= { intSrvGuaranteedIfEntry 2 }
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intSrvGuaranteedIfSlack OBJECT-TYPE
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SYNTAX INTEGER (0..'0FFFFFFF'h)
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MAX-ACCESS read-create
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STATUS current
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DESCRIPTION
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"If a network element uses a certain amount of
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slack, Si, to reduce the amount of resources
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that it has reserved for a particular flow, i,
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the value Si should be stored at the network
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element. Subsequently, if reservation re-
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freshes are received for flow i, the network
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element must use the same slack Si without any
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further computation. This guarantees consisten-
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cy in the reservation process.
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As an example for the use of the slack term,
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consider the case where the required end-to-end
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delay, Dreq, is larger than the maximum delay
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of the fluid flow system. In this, Ctot is the
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sum of the Backlog terms end to end, and Dtot
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is the sum of the delay terms end to end. Dreq
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is obtained by setting R=r in the fluid delay
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formula, and is given by
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b/r + Ctot/r + Dtot.
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In this case the slack term is
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S = Dreq - (b/r + Ctot/r + Dtot).
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The slack term may be used by the network ele-
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ments to adjust their local reservations, so
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that they can admit flows that would otherwise
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have been rejected. A service element at an in-
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termediate network element that can internally
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differentiate between delay and rate guarantees
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can now take advantage of this information to
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lower the amount of resources allocated to this
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flow. For example, by taking an amount of slack
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s <= S, an RCSD scheduler [5] can increase the
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local delay bound, d, assigned to the flow, to
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d+s. Given an RSpec, (Rin, Sin), it would do so
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by setting Rout = Rin and Sout = Sin - s.
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Similarly, a network element using a WFQ
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scheduler can decrease its local reservation
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from Rin to Rout by using some of the slack in
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the RSpec. This can be accomplished by using
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the transformation rules given in the previous
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section, that ensure that the reduced reserva-
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tion level will not increase the overall end-
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to-end delay."
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::= { intSrvGuaranteedIfEntry 3 }
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intSrvGuaranteedIfStatus OBJECT-TYPE
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SYNTAX RowStatus
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MAX-ACCESS read-create
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STATUS current
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DESCRIPTION
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"'valid' on interfaces that are configured for
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the Guaranteed Service."
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::= { intSrvGuaranteedIfEntry 4 }
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-- No notifications are currently defined
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-- conformance information
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intSrvGuaranteedGroups OBJECT IDENTIFIER
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::= { intSrvGuaranteedConformance 1 }
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intSrvGuaranteedCompliances OBJECT IDENTIFIER
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::= { intSrvGuaranteedConformance 2 }
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-- compliance statements
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intSrvGuaranteedCompliance MODULE-COMPLIANCE
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STATUS current
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DESCRIPTION
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"The compliance statement "
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MODULE -- this module
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MANDATORY-GROUPS {
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intSrvGuaranteedIfAttribGroup
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}
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::= { intSrvGuaranteedCompliances 1 }
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intSrvGuaranteedIfAttribGroup OBJECT-GROUP
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OBJECTS {
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intSrvGuaranteedIfBacklog,
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intSrvGuaranteedIfDelay,
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intSrvGuaranteedIfSlack,
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intSrvGuaranteedIfStatus
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}
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STATUS current
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DESCRIPTION
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"These objects are required for Systems sup-
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porting the Guaranteed Service of the Integrat-
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ed Services Architecture."
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::= { intSrvGuaranteedGroups 2 }
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END
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