Table Of Contents
ATM Policing by Service Category for SVC/SoftPVC
Related Features and Technologies
Supported Standards, MIBs, and RFCs
Configuring ATM Policing by Service Category for SVC/SoftPVC
Verifying ATM Policing by Service Category for SVC/SoftPVC
Monitoring and Maintaining ATM Policing by Service Category for SVC/SoftPVC
Example: Monitoring and Maintaining ATM Policing by Service Category for SVC/SoftPVC
ATM Policing by Service Category for SVC/SoftPVC
Feature History
Release Modification12.2(4)B
This feature was introduced on the Cisco 6400 NSP.
12.2(13)T
This command was integrated into Cisco IOS Release 12.2(13)T.
This document describes the ATM Policing by Service Category for SVC/SoftPVC feature in Cisco IOS Release 12.2(13)T and includes the following sections:
•Supported Standards, MIBs, and RFCs
•Monitoring and Maintaining ATM Policing by Service Category for SVC/SoftPVC
Feature Overview
When configured, an ATM switch at the network side of a user-to-network (UNI) interface polices the flow of cells in the forward (into the network) direction of a virtual connection. These traffic policing mechanisms are known as usage parameter control (UPC). With UPC, the switch determines whether received cells comply with the negotiated traffic management values and takes one of the following actions on violating cells:
•Pass the cell without changing the cell loss priority (CLP) bit in the cell header.
•Tag the cell with a CLP bit value of 1.
•Drop (discard) the cell.
The ATM Policing by Service Category for SVC/SoftPVC feature enables you to specify which traffic to police, based on service category, on switched virtual circuits (SVCs) or terminating VCs on the destination end of a soft VC.
For more information on UPC, see the "Traffic and Resource Management" chapter in the Guide to ATM Technology.
Benefits
This feature enables you to select which and how traffic is affected by UPC. For example, you can configure your switch to pass all UBR traffic, but tag all other traffic types.
Related Features and Technologies
•Intelligent early packet discard (EPD)
•Intelligent partial (tail) packet discard
Related Documents
•ATM Switch Router Software Configuration Guide
•ATM and Layer 3 Switch Router Command Reference
•Guide to ATM Technology
•ATM Forum UNI 3.1 Specification
Supported Platforms
This feature is supported on the node switch processor (NSP) of the Cisco 6400 carrier-class broadband aggregator.
Supported Standards, MIBs, and RFCs
Standards
None
MIBs
CISCO-ATM-IF-MIB.my—New objects were created for per-service category SVC UPC intent.
To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
RFCs
None
Configuration Tasks
See the following sections for configuration tasks for the ATM Policing by Service Category for SVC/SoftPVC feature. Each task in the list is identified as either required or optional:
•Configuring ATM Policing by Service Category for SVC/SoftPVC (Required)
•Verifying ATM Policing by Service Category for SVC/SoftPVC (Optional)
Configuring ATM Policing by Service Category for SVC/SoftPVC
To configure the ATM Policing by Service Category for SVC/SoftPVC feature, use the following commands beginning in global configuration mode:
Verifying ATM Policing by Service Category for SVC/SoftPVC
Step 1 Enter the show atm vc or show atm vp EXEC command to display the UPC mode for a particular VC or VP.
Switch# show atm vc int atm 0/0/1 2 120Interface:ATM0/0/1, Type:oc3suniVPI = 2 VCI = 120Status:DOWNTime-since-last-status-change:1w1dConnection-type:PVCCast-type:point-to-multipoint-leafPacket-discard-option:disabledUsage-Parameter-Control (UPC):passWrr weight:2Number of OAM-configured connections:0OAM-configuration:disabledOAM-states: Not-applicableCross-connect-interface:ATM0/0/1, Type:oc3suni...Step 2 Enter the show atm interface EXEC command. If the UPC mode is not the same for all service categories, the "Svc Upc Intent" field displays "by sc."
Switch# show atm interface atm 8/0/1Interface: ATM8/0/1 Port-type: oc3suniIF Status: UP Admin Status: upAuto-config: enabled AutoCfgState: completedIF-Side: Network IF-type: NNIUni-type: not applicable Uni-version: not applicableMax-VPI-bits: 8 Max-VCI-bits: 14Max-VP: 255 Max-VC: 16383ConfMaxSvpcVpi:255 CurrMaxSvpcVpi:255ConfMaxSvccVpi:255 CurrMaxSvccVpi:255ConfMinSvccVci:35 CurrMinSvccVci:35Svc Upc Intent:by sc Signalling: EnabledATM Address for Soft VC:47.0091.8100.0000.0002.b9ae.9301.4000.0c84.0010.00Configured virtual links:PVCLs SoftVCLs SVCLs TVCLs PVPLs SoftVPLs SVPLs Total-Cfgd Inst-Conns3 4 0 0 1 0 0 8 7Logical ports(VP-tunnels): 0Input cells: 3036674 Output cells: 30368165 minute input rate: 0 bits/sec, 0 cells/sec5 minute output rate: 0 bits/sec, 0 cells/secInput AAL5 pkts:1982638, Output AAL5 pkts:1982687, AAL5 crc errors:0
Troubleshooting Tips
If a VC is not configured with the appropriate UPC mode, make sure that the VC was set up after the atm svc-upc-intent command was configured. Changes to the UPC mode take affect after the VC is torn down and set up again.
Monitoring and Maintaining ATM Policing by Service Category for SVC/SoftPVC
Use the commands listed below to monitor and maintain ATM Policing by Service Category for SVC/SoftPVC:
Example: Monitoring and Maintaining ATM Policing by Service Category for SVC/SoftPVC
Switch# show atm vc interface atm 3/0/1.51 51 16Interface: ATM3/0/1.51, Type: oc3suniVPI = 51 VCI = 16Status: DOWNTime-since-last-status-change: 2w0dConnection-type: PVCCast-type: point-to-pointPacket-discard-option: enabledUsage-Parameter-Control (UPC): passWrr weight: 32Number of OAM-configured connections: 0OAM-configuration: disabledOAM-states: Not-applicableCross-connect-interface: ATM2/0/0, Type: ATM Swi/ProcCross-connect-VPI = 0Cross-connect-VCI = 73Cross-connect-UPC: passCross-connect OAM-configuration: disabledCross-connect OAM-state: Not-applicableEncapsulation: AAL5ILMIThreshold Group: 6, Cells queued: 0Rx cells: 0, Tx cells: 0Tx Clp0:0, Tx Clp1: 0Rx Clp0:0, Rx Clp1: 0Rx Upc Violations:0, Rx cell drops:0Rx pkts:0, Rx pkt drops:0Rx connection-traffic-table-index: 6Rx service-category: UBR (Unspecified Bit Rate)Rx pcr-clp01: 424Rx scr-clp01: noneRx mcr-clp01: noneRx cdvt: 1024 (from default for interface)Rx mbs: noneTx connection-traffic-table-index: 6Tx service-category: UBR (Unspecified Bit Rate)Tx pcr-clp01: 424Tx scr-clp01: noneTx mcr-clp01: noneTx cdvt: noneTx mbs: noneNo AAL5 connection registeredConfiguration Examples
This section provides the following configuration example:
Non-UBR Traffic Policing
In the following example, the UBR traffic on ATM 3/0/0 is passed while all other traffic is policed:
Switch(config)# interface atm 3/0/0Switch(config-if)# atm svc-upc-intent ubr passSwitch(config-if)# atm svc-upc-intent cbr tagSwitch(config-if)# atm svc-upc-intent vbr-rt tagSwitch(config-if)# atm svc-upc-intent vbr-nrt tagSwitch(config-if)# atm svc-upc-intent abr dropCommand Reference
This section documents one modified command. All other commands used with this feature are documented in the ATM and Layer 3 Switch Router Command Reference and the Cisco IOS Release 12.2 command reference publications.
atm svc-upc-intent
To change the intended UPC mode to use on the cell flow received into the switch fabric for SVCs or destination legs of soft PVCs on an interface, use the atm svc-upc-intent command in interface configuration mode. Any change in this parameter is applied to SVCs or soft PVCs subsequently established on the interface. To assign the default value to the parameter, use the no form of this command.
atm svc-upc-intent [{abr | cbr | vbr-rt | vbr-nrt | ubr}] {tag | pass | drop}
no atm svc-upc-intent
Syntax Description
Defaults
Pass for all service categories
Command Modes
Interface configuration
Command History
Usage Guidelines
This configuration parameter determines the UPC to use for SVCs and for the destination leg of soft VC and VP. If policing is desired, it should be applied once for traffic entering a network.
Examples
In the following example, the intended UPC for SVCs on an interface is set to tagging.
Switch(config-if)# atm svc-upc-intent tagIn the following example, the UBR traffic on an interface is passed while all other traffic is policed:
Switch(config-if)# atm svc-upc-intent ubr passSwitch(config-if)# atm svc-upc-intent cbr tagSwitch(config-if)# atm svc-upc-intent vbr-rt tagSwitch(config-if)# atm svc-upc-intent vbr-nrt tagSwitch(config-if)# atm svc-upc-intent abr dropRelated Commands
Glossary
ABR—available bit rate. QoS class defined by the ATM Forum for ATM networks. ABR is used for connections that do not require timing relationships between source and destination. ABR provides no guarantees in terms of cell loss or delay, providing only best-effort service. Traffic sources adjust their transmission rate in response to information they receive describing the status of the network and its capability to successfully deliver data. Compare with CBR, UBR, and VBR.
CBR—constant bit rate. QoS class defined by the ATM Forum for ATM networks. CBR is used for connections that depend on precise clocking to ensure undistorted delivery. Compare with ABR, UBR, and VBR.
CLP—cell loss priority. Field in the ATM cell header that determines the probability of a cell being dropped if the network becomes congested. Cells with CLP = 0 are insured traffic, which is unlikely to be dropped. Cells with CLP = 1 are best-effort traffic, which might be dropped in congested conditions to free up resources to handle insured traffic.
PVC—permanent virtual circuit (or connection). Virtual circuit that is permanently established. PVCs save bandwidth associated with circuit establishment and tear down in situations where certain virtual circuits must exist all the time. In ATM terminology, called a permanent virtual connection. Compare with SVC. See also virtual circuit.
soft PVC—A PVC-SVC hybrid in which only the two terminating virtual connection links (VCLs) at either end are permanent and the rest of the VCLs are switched (SVC). Like the PVC, a soft PVC is permanent and the called party cannot drop the connection. Like the SVC, a soft PVC is automatically rerouted if a switch or link in the path fails.
SVC—switched virtual circuit. Virtual circuit that is dynamically established on demand and is torn down when transmission is complete. SVCs are used in situations where data transmission is sporadic. See also virtual circuit. Called a switched virtual connection in ATM terminology. Compare with PVC.
tagged traffic—ATM cells that have their CLP bit set to 1. If the network is congested, tagged traffic can be dropped to ensure the delivery of higher-priority traffic. Sometimes called DE traffic. See also CLP.
traffic policing—Process used to measure the actual traffic flow across a given connection and compare it to the total admissible traffic flow for that connection. Traffic outside of the agreed upon flow can be tagged (where the CLP bit is set to 1) and can be discarded en route if congestion develops. Traffic policing is used in ATM, Frame Relay, and other types of networks. Also known as admission control, permit processing, rate enforcement, and UPC. See also tagged traffic.
UBR—unspecified bit rate. QoS class defined by the ATM Forum for ATM networks. UBR allows any amount of data up to a specified maximum to be sent across the network but there are no guarantees in terms of cell loss rate and delay. Compare with ABR, CBR, and VBR.
UPC—usage parameter control. See traffic policing.
VBR—variable bit rate. QoS class defined by the ATM Forum for ATM networks. VBR is subdivided into a real time (RT) class and non-real time (NRT) class. VBR (RT) is used for connections in which there is a fixed timing relationship between samples. VBR (NRT) is used for connections in which there is no fixed timing relationship between samples but that still need a guaranteed QoS. Compare with ABR, CBR, and UBR.
virtual circuit—Logical circuit created to ensure reliable communication between two network devices. A virtual circuit is defined by a VPI/VCI pair, and can be either permanent (PVC) or switched (SVC). Virtual circuits are used in Frame Relay and X.25. In ATM, a virtual circuit is called a virtual channel. Sometimes abbreviated VC.