Table of Contents
Configuring Resource Management
Resource Management Functions
Switch Fabric Functionality (Catalyst 8540 MSR)
Processor Feature Card Functionality (Catalyst 8510 MSR and LightStream 1010)
Configuring Global Resource Management
Configuring the Physical Interface
Configuring the Physical and Logical Interface Parameters
Configuring Interface Overbooking
Configuring Framing Overhead
Configuring Resource Management
This chapter describes resource management, which involves modeling and managing switch, interface, and connection resources. Such resources include equivalent bandwidth and buffering to support the provision of specified traffic classes.
Note This chapter provides advanced configuration instructions for the Catalyst 8540 MSR,
Catalyst 8510 MSR, and LightStream 1010 ATM switch routers. For detailed descriptions of traffic
management mechanisms and their operation, refer to the Guide to ATM Technology. For complete
descriptions of the commands mentioned in this chapter, refer to the ATM Switch Router Command
Reference publication.
This chapter includes the following sections:
Note The traffic and resource management features of the ATM switch router are presented in a
different order in this guide and in the Guide to ATM Technology. In this guide the sequence of
features follows configuration scope and proceeds from global to per-interface features. In the Guide
to ATM Technology the sequence of features follows the phases of a connection and proceeds from
traffic contract to management of hardware resources.
Resource Management Functions
The ATM switch router resource management software provides the following functions:
- Network management interface—Includes operational configuration changes (take place immediately), proposed configuration changes (take place on restart), user interface, and status.
- Default quality of service (QoS) objective table management—Since User-Network Interface 3 (UNI 3) signalling does not provide information elements to signal QoS values, resource management provides a table that contains default values for QoS.
- Connection Traffic Table (CTT) management—Rather than store traffic parameters for each connection in that connection's data structure, resource management manages a table of connection traffic parameters, used by network and connection management.
- Hardware resource management (Catalyst 8540 MSR)—The switch processor feature card provides functionality that include statistic collection, and traffic policing (UPC). See the section "Configuring Global Resource Management" for detailed information.
- Hardware resource management (Catalyst 8510 MSR and LightStream 1010)—Different sets of functionality are available with feature card per-class queueing (FC-PCQ) and feature card per-flow queueing (FC-PFQ). FC-PCQ features include switch cell priority limits, interface queue sizes, and thresholds. FC-PFQ features include threshold group configuration. The interface pacing feature is available with both feature cards. See the section "Processor Feature Card Functionality (Catalyst 8510 MSR and LightStream 1010)" for detailed information.
- Resource Call Admission Control (RCAC)—Determines whether a virtual channel connection/virtual path connection (VCC/VPC) can be admitted (allowed to be set up), based on the available connection resources and requested traffic characteristics.
- Logical interface creation and deletion.
- Private Network-Network Interface (PNNI) metrics—resource management supplies PNNI with link metrics for connection routing.
Switch Fabric Functionality (Catalyst 8540 MSR)
The switch fabric for the Catalyst 8540 MSR provides the required ATM Forum Traffic Management features as described in Table 8-1.
Table 8-1 Switch Processor Feature Card
| Feature
|
Description
|
Traffic classes:
|
CBR1, VBR-RT2, VBR-NRT3, UBR4, ABR5(EFCI)6
|
Output queuing
|
Per-VC or per-VP
|
Output scheduling
|
RS7 and WRR8
|
Intelligent early packet discard
|
Multiple dynamic thresholds
|
Intelligent tail (partial) packet discard
|
Supported
|
Selective cell marking and discard
|
Multiple, weighted, dynamic thresholds
|
Shaping
|
Per-port pacing, per-CBR VC, per-CBR transit VP, per-shaped CBR VP tunnel (128 shaped VP tunnels total), and Hierarchical VP tunnels
|
Policing (UPC9)10
|
Dual leaky bucket
|
Frame mode VC-merge
|
Supported
|
Point-to-multipoint VC (multicast)
|
Multiple leafs per output port, per point-to-multipoint
|
Network clock switchover10
|
Programmable clock selection criteria
|
Nondisruptive snooping
|
Per-VC or per-VP
|
Hierarchical VP tunnel
|
Maximum of 240 VP tunnels.
|
| CBR = constant bit rate
RT-VBR = variable bit rate real-time
VBR-NRT = variable bit rate-non real-time
UBR = unspecified bit rate
ABR = available bit rate
EFCI = explicit forward congestion indication
RS = rate scheduling
WRR = weighted round robin
UPC = usage parameter control
Performed by feature card
|
Processor Feature Card Functionality (Catalyst 8510 MSR and LightStream 1010)
Two types of feature cards are available for the Catalyst 8510 MSR and LightStream 1010 ATM switch routers: FC-PCQ and FC-PFQ. Each card provides the required ATM Forum Traffic Management features. FC-PCQ contains a subset of the FC-PFQ features, as described in Table 8-2.
Note To determine which feature card you have installed, enter the show hardware EXEC
command. Either FC-PCQ or FC-PFQ displays in the Ctrlr-Type column.
Table 8-2 FC-PCQ and FC-PFQ Feature Comparison
| Feature
|
FC-PCQ
|
FC-PFQ
|
Traffic classes
|
CBR1, VBR-RT2, VBR-NRT3, ABR4 (EFCI5 and RR6), UBR7
|
CBR, RT-VBR, NRT-VBR, ABR (EFCI and RR), UBR
|
Output queuing
|
Four classes per port
|
Per-VC or per-VP
|
Output scheduling
|
SP8
|
RS9 and WRR10
|
Intelligent early packet discard
|
Multiple fixed thresholds
|
Multiple dynamic thresholds
|
Intelligent tail (partial) packet discard
|
Supported
|
Supported
|
Selective cell marking and discard
|
Multiple fixed thresholds
|
Multiple, weighted, dynamic thresholds
|
Shaping
|
Per-port (pacing)
|
Per-port pacing, per-CBR VC, per-CBR transit VP, per-shaped CBR VP tunnel (128 shaped VP tunnels total), and Hierarchical VP tunnels
|
Policing (UPC11)
|
Dual mode, single leaky bucket
|
Dual leaky bucket
|
Point-to-multipoint VC (multicast)
|
One leaf per output port, per point-to-multipoint
|
Multiple leafs per output port, per point-to-multipoint
|
Network clock switch over
|
Automatic upon failure
|
Programmable clock selection criteria
|
Nondisruptive snooping
|
Per-port transmit or receive
|
Per-VC or per-VP
|
Hierarchical VP tunnel12
|
-
|
Maximum of 62 VP tunnels.
|
| CBR = constant bit rate
RT-VBR = variable bit rate real-time
VBR-NRT = variable bit rate-non real-time
ABR = available bit rate
EFCI = explicit forward congestion indication
RR = relative rate
UBR = unspecified bit rate
SP = strict priority
RS = rate scheduling
WRR = weighted round robin
UPC = usage parameter control
Available with FC-PFQ only
|
Configuring Global Resource Management
Global resource management configurations affect all interfaces on the switch. The following sections describe global resource management tasks:
Configuring the Default QoS Objective Table
Resource management provides a table of default objective values for QoS for guaranteed service categories. These values—either metrics or attributes—are used as the criteria for connection setup requirements.
Note Default objective values for QoS for guaranteed service categories can be configured for
UNI 4.0 signalling.
Table 8-3 lists the default values of the QoS objective table.
Table 8-3 Default QoS Objective Table
Service
Category
|
Max Cell Transfer
Delay (clp01)
|
Peak-to-Peak Cell Delay Variation (clp01)
|
Cell Loss
Ratio (clp0)
|
Cell Loss Ratio
(clp0+1)
|
cbr
|
Undefined
|
Undefined
|
Undefined
|
Undefined
|
vbr-rt
|
Undefined
|
Undefined
|
Undefined
|
Undefined
|
vbr-nrt
|
—
|
—
|
Undefined
|
Undefined
|
Row Contents
Each objective can have a defined or undefined value. If undefined, the objective is not considered in connection setup. The table should be configured with the same values for an entire network.
To configure the default QoS objective table, perform the following tasks in global configuration mode:
| Step
|
Command
|
Purpose
|
| 1
|
atm qos default {cbr | vbr-rt} max-cell-transfer-delay {microseconds | any}
|
Selects the ATM QoS default CBR or VBR-RT maximum cell transfer delay.
|
| 2
|
atm qos default {cbr | vbr-rt} peak-to-peak- cell-delay variation {microseconds | any}
|
Selects the ATM QoS default CBR or VBR-RT peak-to-peak cell delay variation.
|
| 3
|
atm qos default {cbr | vbr-rt | vbr-nrt} max-cell-loss-ratio [clp0 | clp1plus0] {loss-ratio-exponent | any}
|
Selects the ATM QoS default CBR, VBR-RT, or VBR-NRT maximum cell loss ratio.
|
Example
The following example shows how to change the CBR maximum cell loss ratio objective for cell loss priority (CLP) = 0+1 to 10-12 cells per second:
Switch(config)#
atm qos default cbr max-cell-loss-ratio clp1plus0 12
Displaying the ATM QoS Objective Table
To display the default QoS objective table, use the following privileged EXEC command:
| Command
|
Purpose
|
show atm qos-defaults
|
Displays the ATM QoS objective table configuration.
|
The per-service category, maximum cell transfer delay, peak-to-peak cell delay variation, and maximum cell loss ratio objectives are displayed.
Example
The ATM QoS objective table configuration is displayed in the following example:
Switch#
show atm qos-defaults
Default QoS objective table:
Max cell transfer delay (in microseconds): any cbr, any vbr-rt
Peak-to-peak cell delay variation (in microseconds): any cbr, any vbr-rt
Max cell loss ratio for CLP0 cells: any cbr, any vbr-rt, any vbr-nrt
Max cell loss ratio for CLP0+1 cells: 10**(-12) cbr, any vbr-rt, any vbr-nrt
Configuring the Switch Oversubscription Factor (Catalyst 8510 MSR and LightStream 1010)
The switch oversubscription factor (OSF) feature on the Catalyst 8510 MSR and LightStream 1010 ATM switch routers is used in determining initial port maximum queue sizing for VBR-NRT and available bit rate/unspecified bit rate (ABR/UBR) queues.
Note Over subscription factor configuration is only possible on switches with FC-PCQ installed.
The size of the VBR-NRT queue and ABR-UBR queues is determined by the following equations, where the default size of the CBR and VBR queues vary by interface type, as listed in Table 8-4:
Default Size (VBR-NRT) = 0.25 * ((OSF * 2048) - DefaultSize(CBR) - DefaultSize (VBR-RT))
Default Size (ABR-UBR) = 0.75 * ((OSF * 2048) - DefaultSize(CBR) - DefaultSize (VBR-RT))
Table 8-4
| Interface Type
|
Default Max Size CBR Queue
|
Default Max Size Type
VBR-RT Queue
|
SONET
|
256
|
256
|
DS3/E3
|
256
|
512
|
Default CBR and VBR Determined by Interface Type
To configure the OSF, use the following global configuration command:
| Command
|
Purpose
|
atm over-subscription-factor o-value
|
Configures the switch OSF from 1 to 32.
|
Note This value can be changed at any time, but it is only used at start-up and when a module is
hot-swapped from the chassis.
Example
The following example shows how to set the switch over subscription factor to 16:
Switch(config)#
atm over-subscription-factor 16
Displaying the OSF Configuration (Catalyst 8510 MSR and LightStream 1010)
To display the OSF configuration, use the following privileged EXEC command:
| Command
|
Purpose
|
show atm resource
|
Displays the OSF configuration.
|
Note The following examples differ depending on the feature card installed in your switch.
Examples
The following example shows the switch OSF configuration with FC-PCQ installed:
Switch>
show atm resource
Over-subscription-factor 16 Sustained-cell-rate-margin-factor 1%
Atm service-category-limit (in cells):
64544 cbr 64544 vbr-rt 64544 vbr-nrt 64544 abr-ubr
Cells per service-category:
0 cbr 0 vbr-rt 0 vbr-nrt 0 abr-ubr
Configuring the Service Category Limit (Catalyst 8510 MSR and LightStream 1010)
The service category limit configuration restricts the number of cells admitted into the switch, as determined by the type of output queues.
Note Service category limit configuration is only possible on switches with FC-PCQ installed.
 | Caution
Setting a service category limit to 0 causes the connection requests for the associated service categories to be rejected. |
To configure the service category limits, use the following global configuration command:
| Command
|
Purpose
|
atm service-category-limit {cbr | vbr-rt | vbr-nrt | abr-ubr} value
|
Configures ATM service category limits for a specific output queue.
|
Note The atm service-category-limit command affects all connections, including those already
established.
Example
The following example shows how to change the service category limit for the CBR cells within the switch fabric to 3000 cells:
Switch(config)#
atm service-category-limit cbr 3000
Displaying the Service Category Limit Configuration (Catalyst 8510 MSR and LightStream 1010)
To display the service category limit configuration, use the following privileged EXEC command:
| Command
|
Purpose
|
show atm resource
|
Displays the service category limits configuration.
|
Example
The following example shows the service category limits configuration:
Switch>
show atm resource
Over-subscription-factor 16 Sustained-cell-rate-margin-factor 1%
Atm service-category-limit (in cells):
3000 cbr 64544 vbr-rt 64544 vbr-nrt 64544 abr-ubr
Cells per service-category:
0 cbr 0 vbr-rt 0 vbr-nrt 0 abr-ubr
Configuring the ABR Congestion Notification Mode (Catalyst 8510 MSR and LightStream 1010)
The ABR congestion notification mode changes the type of notification used on ABR connections to alert the end station of congestion. ABR mode configuration determines whether ABR uses explicit forward congestion indication (EFCI) marking, relative-rate marking, or both, for rate management on ABR connections.
The global configuration function is used to modify the ABR mode selection for all ABR connections.
To configure the ABR mode, use the following global configuration command:
| Command
|
Purpose
|
atm abr-mode {efci | relative-rate | all}
|
Configures ABR congestion notification mode.
|
Note The atm abr-mode command affects all connections, including those already established.
Example
The following example shows how to configure the entire switch to set the EFCI bit whenever a cell arrives on a congested ABR connection:
Switch(config)#
atm abr-mode efci
Displaying the ABR Congestion Notification Mode Configuration (Catalyst 8510 MSR and LightStream 1010)
To display the ABR congestion notification mode configuration, use the following privileged EXEC command:
| Command
|
Purpose
|
show atm resource
|
Displays the ABR congestion notification mode configuration.
|
Note The following examples differ depending on the feature card installed in your switch.
Examples
The following example shows the ABR mode configuration with FC-PCQ installed:
Switch>
show atm resource
Over-subscription-factor 16 Sustained-cell-rate-margin-factor 1%
Abr-mode: efci
Atm service-category-limit (in cells):
3000 cbr 64544 vbr-rt 64544 vbr-nrt 64544 abr-ubr
Cells per service-category:
0 cbr 0 vbr-rt 0 vbr-nrt 0 abr-ubr
The following example shows the ABR mode configuration with FC-PFQ installed:
Switch>
show atm resource
Over-subscription-factor 8 Sustained-cell-rate-margin-factor 1%
Abr-mode: efci
Service Category to Threshold Group mapping:
cbr 1 vbr-rt 2 vbr-nrt 3 abr 4 ubr 5
Group Max Max Q Min Q Q thresholds Cell Name
cells limit limit Mark Discard count
---------------------------------------------------
1 65535 63 63 25 % 87 % 0 cbr-default-tg
2 65535 127 127 25 % 87 % 0 vbrrt-default-tg
3 65535 511 31 25 % 87 % 0 vbrnrt-default-tg
4 65535 511 31 25 % 87 % 0 abr-default-tg
5 65535 511 31 25 % 87 % 0 ubr-default-tg
6 65535 1023 1023 25 % 87 % 0 well-known-vc-tg
Configuring the Connection Traffic Table
A row in the CTT must be created for each unique combination of traffic parameters. Virtual path links (VPLs) and virtual channel links (VCLs) then specify traffic by specifying a row in the table per flow (receive and transmit). Many VCL/VPLs can refer to the same row in the traffic table.
The following two subsections outline the differences in the CTT feature according to platform and feature card.
CTT Supported Features (Catalyst 8540 MSR)
The rows corresponding to various service categories support the following features on the Catalyst 8540 MSR.
- Non-zero minimum cell rate (MCR) for UBR+ service categories. UBR+ is a variant of UBR, in which peak cell rate (PCR), MCR, and cell delay variation tolerance (CDVT) are specified in the traffic contract, with a guarantee on MCR.
- Both CDVT and maximum burst size (MBS) for VBR rows. Dual-leaky-bucket UPC is allowed.
- Whether SCR applies to either the CLP0 or CLP0+1 flow of cells. Only one or the other of these flows can be policed.
CTT Supported Features (Catalyst 8510 MSR and LightStream 1010)
ATM switch routers with FC-PFQ and software version 11.2(8) or later have more rows of various service categories that allow you to specify the following features:
- Non-zero minimum cell rate (MCR) for ABR and UBR+ service categories. UBR+ is a variant of UBR, in which peak cell rate (PCR), MCR, and cell delay variation tolerance (CDVT) are specified in the traffic contract, with a guarantee on MCR.
- Both CDVT and maximum burst size (MBS) for VBR rows. FC-PFQ allows dual-leaky-bucket UPC.
- Whether SCR applies to either the CLP0 or CLP0+1 flow of cells. FC-PFQ can police one or the other of these flows.
If your switch has FC-PCQ installed on the route processor you cannot take advantage of these new capabilities. CTT rows specifying these new parameters can be configured with FC-PCQ installed, with the following effect:
- Non-zero MCR is not supported. Requests for connections specifying non-zero MCR are rejected.
- On VBR connections, only SCR and MBS are used for UPC, and policing is done only on the CLP0+1 flow of cells.
PVC Connection Traffic Rows
The CTT in a permanent virtual channel (PVC) setup requires storing PVC traffic values in a CTT data structure. Rows used for PVCs are called stable rows, and contain traffic parameters.
SVC Connection Traffic Rows
The CTT in a switched virtual circuit (SVC) setup provides a row identifier that Simple Network Management Protocol (SNMP) or the user interface can use to read or display SVC traffic parameters. A CTT row index is stored in the connection-leg data structure for each flow of the connection.
Note Rows cannot be deleted while in use by a connection.
CTT Row Allocations and Defaults
To make CTT management software more efficient, the CTT row-index space is split into rows allocated as a result of signalling and rows allocated from the CLI and SNMP. Table 8-5 describes the row-index range for both.
Table 8-5 CTT Row-Index Allocation
| Allocated by
|
Row-index range
|
ATOMMIB Traffic Descriptor Table or CLI connection-traffic-table-row creation
|
1 through 1,073,741,823
|
Signalling VxL creation
|
1,073,741,824 through 2,147,483,647
|
Table 8-6 describes the well-known, predefined ATM CTT rows.
Table 8-6 Default ATM Connection Traffic Table Rows
CTT Row
Index
|
Service
Category
|
Peak-Cell-Rate
(CLP01)
|
Sustained-
Cell-Rate
(clp01)
|
Tolerance
|
Use
|
1
|
UBR
|
7113539
|
—
|
None
|
Default PVP/PVC row index
|
2
|
CBR
|
424 kbps
|
—
|
None
|
CBR tunnel well-known (WK) VCs
|
3
|
VBR-RT
|
424 kbps
|
424 kbps
|
50
|
Physical interface/VBR-RT WK VCs
|
4
|
VBR-NRT
|
424 kbps
|
424 kbps
|
50
|
VBR-NRT tunnel WK VCs
|
5
|
ABR
|
424 kbps
|
—
|
None
|
—
|
6
|
UBR
|
424 kbps
|
—
|
None
|
UBR tunnel WK VCs
|
The atm connection-traffic-table-row command supports these service categories: CBR, VBR-RT, VBR-NRT, ABR, and UBR). To create or delete an ATM CTT row, perform the following tasks in global configuration mode:
Note Your CTT feature set depends on the type of feature card that is installed on the
Catalyst 8510 MSR and LightStream 1010 ATM switch routers route processor.
| Step
|
Command
|
Purpose
|
| 1
|
atm connection-traffic-table-row [index row-index] {vbr-rt | vbr-nrt} pcr pcr-value {scr10 scr0} scr-value [mbs mbs-value] [cdvt cdvt_value]
|
Configures an ATM CTT VBR row.
|
| 2
|
atm connection-traffic-table-row [index row-index] cbr pcr pcr-value [cdvt cdvt-value]
|
Configures an ATM CTT CBR row.
|
| 3
|
atm connection-traffic-table-row [index row-index] abr pcr pcr-value [mcr mcr-value] [cdvt cdvt-value]
|
Configures an ATM CTT ABR row.
|
| 4
|
atm connection-traffic-table-row [index row-index] ubr pcr pcr-value [mcr mcr-value] [cdvt cdvt-value]
|
Configures an ATM CTT UBR row.
|
If you do not specify an index row number, the system software determines if one is free and displays it in the allocated index field if the command is successful.
Example
The following example shows how to configure an ATM CTT row with an ABR peak cell rate of 30,000 kilobits per second:
Switch(config)#
atm connection-traffic-table-row abr pcr 30000
Displaying the ATM Connection Traffic Table
To display the CTT configuration, use the following privileged EXEC command:
Example
The following example shows how to display the CTT configuration table:
Switch>
show atm connection-traffic-table
Row Service-category pcr scr/mcr mbs cdvt
4 vbr-nrt 424 424 50 none
2147483645* ubr 0 none none
2147483646* ubr 1 none none
2147483647* ubr 7113539 none none
Configuring the Sustained Cell Rate Margin Factor
The sustained cell rate margin factor determines the aggressiveness of weighting sustainable cell rate (SCR) compared to peak cell rate (PCR). It uses the connection admission control algorithm in admitting VBR connections.
To configure the SCR for your ATM switch router, use the following global configuration command:
| Command
|
Purpose
|
atm sustained-cell-rate-margin-factor s-value
|
Configures the sustained cell rate margin factor.
|
Note The atm sustained-cell-rate-margin-factor command affects subsequent connections but
not connections that are already established.
Example
The following example shows how to configure the SCR margin factor as 85 percent of maximum:
Switch(config)#
atm sustained-cell-rate-margin-factor 85
Displaying the SCR Margin Configuration
To display the SCR margin factor configuration, use the following privileged EXEC command:
| Command
|
Purpose
|
show atm resource
|
Displays the SCR margin factor configuration.
|
Example
The following example shows the SCR margin factor configuration:
Switch>
show atm resource
Sustained-cell-rate-margin-factor 85%
Service Category to Threshold Group mapping:
cbr 1 vbr-rt 2 vbr-nrt 3 abr 4 ubr 5
Module Group Max Max Q Min Q Q thresholds Cell Name
ID cells limit limit Mark Discard count
------------------------------------------------------------
1 1 131071 63 63 25 % 87 % 0 cbr-default-tg
2 131071 127 127 25 % 87 % 0 vbrrt-default-tg
3 131071 511 31 25 % 87 % 0 vbrnrt-default-tg
4 131071 511 31 25 % 87 % 0 abr-default-tg
5 131071 511 31 25 % 87 % 0 ubr-default-tg
6 131071 1023 1023 25 % 87 % 0 well-known-vc-tg
===========================================================
2 1 131071 63 63 25 % 87 % 0 cbr-default-tg
2 131071 127 127 25 % 87 % 0 vbrrt-default-tg
3 131071 511 31 25 % 87 % 0 vbrnrt-default-tg
4 131071 511 31 25 % 50 % 0 abr-default-tg
5 131071 511 31 25 % 87 % 0 ubr-default-tg
6 131071 1023 1023 25 % 87 % 0 well-known-vc-tg
===========================================================
7 1 131071 63 63 25 % 87 % 0 cbr-default-tg
2 131071 127 127 25 % 87 % 0 vbrrt-default-tg
3 131071 511 31 25 % 87 % 0 vbrnrt-default-tg
4 131071 511 31 25 % 87 % 0 abr-default-tg
5 131071 511 31 25 % 87 % 0 ubr-default-tg
6 131071 1023 1023 25 % 87 % 0 well-known-vc-tg
===========================================================
8 1 131071 63 63 25 % 87 % 0 cbr-default-tg
2 131071 127 127 25 % 87 % 0 vbrrt-default-tg
3 131071 511 31 25 % 87 % 0 vbrnrt-default-tg
4 131071 511 31 25 % 87 % 0 abr-default-tg
5 131071 511 31 25 % 87 % 0 ubr-default-tg
6 131071 1023 1023 25 % 87 % 0 well-known-vc-tg
===========================================================
Overview of Threshold Groups
Threshold groups combine VCs/VPs to determine per-connection thresholds, based on the use of memory by the group.
Note Threshold groups are supported on the Catalyst 8540 MSR, and on the Catalyst 8510 MSR
and LightStream 1010 ATM switch routers equipped with the FC-PFQ feature card.
The initial default configuration of per-VC queueing on the switch has all connections of a service category assigned to one threshold group. However, the assignment of service categories to threshold groups is configurable. A service category cannot be mapped to more than one threshold group. If you configure a service category to a threshold group more than once, the last configuration stays in effect. The default assigns each service category to a different threshold group. However, you can assign more than one service category to a threshold group.
Note The configuration of threshold groups is static, not dynamic.
For a description of how the threshold group feature works, refer to the Guide to ATM Technology.
Configuration parameter defaults for the Catalyst 8540 MSR are defined in Table 8-7.
Table 8-7 Threshold Group Configuration Parameter Defaults (Catalyst 8540 MSR)
| Group
|
Maximum Cells1
|
Maximum Queue Limit2
|
Minimum Queue Limit3
|
Mark Threshold4
|
Discard Threshold5
|
Use
|
1
|
131071
|
63
|
63
|
25%
|
87%
|
CBR
|
2
|
131071
|
127
|
127
|
25%
|
87%
|
VBR-RT
|
3
|
131071
|
511
|
31
|
25%
|
87%
|
VBR-NRT
|
4
|
131071
|
511
|
31
|
25%
|
87%
|
ABR
|
5
|
131071
|
511
|
31
|
25%
|
87%
|
UBR
|
6
|
131071
|
1023
|
1023
|
25%
|
87%
|
well-known VCs
|
| Maximum number of cells in threshold group
Maximum (uncongested) per-VC queue limit in cells
Minimum (congested) per-VC queue limit in cells
Marking threshold percent full of per-VC queue
Discard threshold percent full of per-VC queue
|
Configuration parameter defaults for the Catalyst 8510 MSR and LightStream 1010 ATM switch routers are defined in Table 8-8.
Table 8-8 Threshold Group Configuration Parameter Defaults (Catalyst 8510 MSR and LightStream 1010)
| Group
|
Maximum Cells
|
Maximum Queue Limit
|
Minimum Queue Limit
|
Mark Threshold
|
Discard Threshold
|
Use
|
1
|
65535
|
63
|
63
|
25%
|
87%
|
CBR
|
2
|
65535
|
127
|
127
|
25%
|
87%
|
VBR-RT
|
3
|
65535
|
511
|
31
|
25%
|
87%
|
VBR-NRT
|
4
|
65535
|
511
|
31
|
25%
|
87%
|
ABR
|
5
|
65535
|
511
|
31
|
25%
|
87%
|
UBR
|
6
|
65535
|
1023
|
1023
|
25%
|
87%
|
well-known VCs
|
Configuring the Threshold Group
To configure the threshold groups on a ATM switch router, perform the following tasks in global configuration mode:
| Step
|
Command
|
Purpose
|
| 1
|
atm threshold-group service {cbr | vbr-rt | vbr-nrt | abr | ubr} group
|
Assigns a service category to a threshold group.
|
| 2
|
atm threshold-group [module-id module]1 group max-cells number
|
Configures the maximum number of cells queued for all connections that are members of the threshold group.
|
| 3
|
atm threshold-group [module-id module]1 group discard-threshold percent
|
Configures the threshold of per-connection queue-full at which the queue is considered full for CLP discard and EPD.
|
| 4
|
atm threshold-group [module-id module]1 group max-queue-limit number
|
Configures the largest per-vc queue limit that is applied to connections in the threshold group.
|
| 5
|
atm threshold-group [module-id module]1 group min-queue-limit number
|
Configures the smallest per-vc queue-limit that is applied to connections in the threshold group.
|
| 6
|
atm threshold-group [module-id module]1 group name name
|
Configures the name associated with a threshold group.
|
| 7
|
atm threshold-group [module-id module]1 group max-cells number
|
Configures the maximum number of cells queued for specified threshold group for all module-ids.2 Optionally, configure for the specified threshold group for the specified module-id.
|
| 8
|
atm threshold-group [module-id module]1 group marking-threshold percent
|
Configures the threshold of per-connection queue-full at which the queue is considered full for EFCI marking and ABR relative-rate marking.
|
| The module-id identifier is only supported on the Catalyst 8540 MSR.
Each module on the Catalyst 8540 MSR has its own cell memory and threshold groups. There are eight of these modules in a 20 gigabyte configuration. Each module has a 64 kbps cell memory, and the threshold groups can be configured per module. By default, all the threshold groups of all the modules are configured identically.
|
Example
The following example shows how to configure ATM threshold group 5 with a maximum number of cells before the cells are discarded:
