INTEGRATED-SERVICES-GUARANTEED-MIB

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Organization: IETF Integrated Services Working Group

Last Updated: 1995-11-03

Category: Quality of Service

Description: Defines managed objects for the Guaranteed Service extensions to the Integrated Services architecture for quality-of-service management.

IPNetwork Monitor uses several OIDs from this MIB in network discovery and polling the applicable devices. Start monitoring INTEGRATED-SERVICES-GUARANTEED-MIB with a free 30-day trial of IPNetwork Monitor.

What Is INTEGRATED-SERVICES-GUARANTEED-MIB?

INTEGRATED-SERVICES-GUARANTEED-MIB is the standard IETF Integrated Services Working Group MIB (extending INTEGRATED-SERVICES-MIB) describing the Guaranteed Service class of IntServ (RFC 2212), which provides a mathematically bounded delay guarantee for a reserved flow. Its per-interface table records the current queue backlog, computed guaranteed delay, and slack term (the amount of delay budget the flow can give up without violating its guarantee), plus a status object. As a performance/status MIB it lets an administrator confirm a Guaranteed Service reservation's actual delay and backlog against its promised bound. It is deployed on routers implementing IntServ Guaranteed Service (RFC 2212). Engineers can download the INTEGRATED-SERVICES-GUARANTEED-MIB file directly to load it into their MIB browser.

IPNetwork Monitor allows you to monitor SNMP objects defined in INTEGRATED-SERVICES-GUARANTEED-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

Routers implementing IntServ Guaranteed Service (RFC 2212)

Monitoring Examples

An administrator checks intSrvGuaranteedIfDelay against the flow's requested bound to confirm a Guaranteed Service reservation is meeting its delay commitment on a router implementing IntServ.

What Can Be Monitored

guaranteed-service queue backlog and delay bound

Imported Objects

From IF-MIB

ifIndex

OBJECT-TYPE

From INTEGRATED-SERVICES-MIB

intSrv

MODULE-IDENTITY

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

MODULE-IDENTITY
OBJECT-TYPE

From SNMPv2-TC

RowStatus

How to Use in IPNetwork Monitor

Example using intSrvGuaranteedIfBacklog OID:

Select a device implementing INTEGRATED-SERVICES-GUARANTEED-MIB as the target host to create a monitor — the SNMP service should be up and running on it. Click New Monitor, then check SNMP Custom on the Favorites tab, click Next, and confirm the host. On the next page, click Select... to open the built-in SNMP MIB Browser and type intSrvGuaranteedIfBacklog into the Find box to locate it in the OID tree, selecting the specific row/instance you want to monitor since this is a table column, then select it and click OK. The Backlog parameter is the data backlog resulting from the vagaries of how a specific implementation deviates from a strict bit-by- bit service. On the monitor's Main parameters page you can set the target's SNMP port (default 161), credentials, polling interval, and other settings — see the SNMP Monitor help for details. On the State conditions and Alerting tabs, configure when the monitor should change state and trigger an alert; since this is an INTEGER-type OID, Value bounds is the most useful condition here — trigger an alert if the counter increases between polls, since a rising count of errors, failures, or discards often points to a real underlying problem. Click Finish to create the monitor; you can adjust any parameter later.

OIDs

OID symbolic	OID numeric	Type	Access	Description
intSrvGuaranteed	1.3.6.1.2.1.52.5			The MIB module to describe the Guaranteed Service of the Integrated Services Protocol
intSrvGuaranteedObjects	1.3.6.1.2.1.52.5.1
intSrvGuaranteedIfTable	1.3.6.1.2.1.52.5.1.1		not-accessible	The attributes of the system's interfaces ex- ported by the Guaranteed Service.
intSrvGuaranteedIfEntry	1.3.6.1.2.1.52.5.1.1.1		not-accessible	The reservable attributes of a given inter- face.
INT intSrvGuaranteedIfBacklogEx	1.3.6.1.2.1.52.5.1.1.1.1	INTEGER	read-create	The Backlog parameter is the data backlog resulting from the vagaries of how a specific implementation deviates from a strict bit-by- bit service. So, for instance, for packetized weighted fair queueing, Backlog is set to the Maximum Packet Size. The Backlog term is measured in units of bytes. An individual element can advertise a Backlog value between 1 and 228 (a little over 250 megabytes) and the total added over all ele- ments can range as high as (232)-1. Should the sum of the different elements delay exceed (232)-1, the end-to-end error term should be (232)-1.
INT intSrvGuaranteedIfDelay	1.3.6.1.2.1.52.5.1.1.1.2	INTEGER	read-create	The Delay parameter at each service element should be set to the maximum packet transfer delay (independent of bucket size) through the service element. For instance, in a simple router, one might compute the worst case amount of time it make take for a datagram to get through the input interface to the processor, and how long it would take to get from the pro- cessor to the outbound interface (assuming the queueing schemes work correctly). For an Eth- ernet, it might represent the worst case delay if the maximum number of collisions is experi- enced. The Delay term is measured in units of one mi- crosecond. An individual element can advertise a delay value between 1 and 228 (somewhat over two minutes) and the total delay added all elements can range as high as (232)-1. Should the sum of the different elements delay exceed (232)-1, the end-to-end delay should be (232)-1.
INT intSrvGuaranteedIfSlack	1.3.6.1.2.1.52.5.1.1.1.3	INTEGER	read-create	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 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.
ROW intSrvGuaranteedIfStatus	1.3.6.1.2.1.52.5.1.1.1.4	RowStatus	read-create	'valid' on interfaces that are configured for the Guaranteed Service.
intSrvGuaranteedNotifications	1.3.6.1.2.1.52.5.2
intSrvGuaranteedConformance	1.3.6.1.2.1.52.5.3
intSrvGuaranteedGroups	1.3.6.1.2.1.52.5.3.1
intSrvGuaranteedIfAttribGroup	1.3.6.1.2.1.52.5.3.1.2			These objects are required for Systems sup- porting the Guaranteed Service of the Integrat- ed Services Architecture.
intSrvGuaranteedCompliances	1.3.6.1.2.1.52.5.3.2
intSrvGuaranteedCompliance	1.3.6.1.2.1.52.5.3.2.1			The compliance statement

RFC description

IntServ guaranteed service MIB defining QoS parameters for interface reservations and traffic guarantees.

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