Table of Contents

Understanding How PVCs Work
Understanding How QoS Traffic Shaping Works

Class of Service
Traffic Shaping
PVC Traffic-Shaping Example

Default PVC Configuration
Configuring PVC-Supported VLANs

Setting Up PVCs in the ATM Cloud
Configuring a PVC-Supported VLAN
Configuring a PVC-Supported VLAN with Traffic Shaping
Unbinding or Removing PVCs from a VLAN

ATM PVC Traffic-Shaping Configuration Examples

Nonredundant Configuration Traffic-Shaping Example

Set up the PVCs within the ATM Cloud.
Set up PVC 1 and PVC 3 on the Catalyst 5000 family Switch 1.
Set up PVC 1 and PVC 2 on the Catalyst 5000 family Switch 2.
Set up PVC 2 and PVC 3 on the Catalyst 5000 family Switch 3.

Redundant Configuration Traffic-Shaping Example

Set up the PVCs within the ATM cloud.
Set up the PVCs on the Catalyst 5000 family Switch 1.
Set up the PVCs on the Catalyst 5000 family Switch 2.

Configuring ATM PVCs and QoS Traffic Shaping

This chapter describes how to configure permanent virtual connection (PVC)-supported VLANs and PVC-supported VLANs with quality of service (QoS) traffic shaping on the ATM modules for the Catalyst 5000 and 6000 family switches.

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Note   For information on installing Catalyst 5000 family ATM modules, refer to the Catalyst 5000 Family Module Installation Guide. For information on installing Catalyst 6000 family ATM modules, refer to the Catalyst 6000 Family Module Installation Guide.

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Note   For syntax and usage information for the commands used in this chapter, see "Command Reference."

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This chapter consists of the following sections:

• Understanding How PVCs Work

• Understanding How QoS Traffic Shaping Works

• Default PVC Configuration

• Configuring PVC-Supported VLANs

• ATM PVC Traffic-Shaping Configuration Examples

Understanding How PVCs Work

PVC-based ATM links allow Catalyst 5000 and 6000 family switches to connect to each other through ATM interfaces over PVCs. You can configure one or more PVCs for each VLAN on every Catalyst 5000 or 6000 family ATM module. Connectivity can be back-to-back or through an ATM switch cloud, using RFC 1483-compliant, bridged Logical Link Control/Subnetwork Access Protocol (LLC/SNAP) packet encapsulation.

Note   Traffic cannot be bridged between ports in the same VLAN if these ports are configured for PVCs.

When you create a PVC, you create a virtual channel descriptor (VCD) and attach it to the virtual path identifier (VPI) and virtual channel identifier (VCI). A VCD identifies the VPI-VCI pair for a particular packet. The ATM module requires this feature to manage packet transmission. The number chosen for the VCD is independent of the VPI-VCI pair used.

Understanding How QoS Traffic Shaping Works

You can configure QoS traffic shaping with ATM PVC traffic-shaping software releases 50.1 or 51.1 and with ATM software releases 11.3WA4 and 12.0W5.

QoS consists of the following contracts:

• Class of service (CoS)

• Traffic shaping

• Traffic policing

In the Catalyst 5000 and 6000 family ATM module software, CoS is determined when you specify the traffic-shaping parameters. The following sections describe how CoS and traffic shaping functions in the Catalyst 5000 and 6000 ATM family modules. Traffic policing is not supported on the ATM modules.

Note   Software releases 50.1 and 51.1 are separate images from the Catalyst 5000 family LANE/MPOA software; software releases 50.1 and 51.1 do not support traffic shaping with LANE and support only RFC 1483-bridged Ethernet SNAP-encapsulated PVCs with peak cell-rate shaping.

Caution The ATM single PHY OC-3, dual PHY OC-3, and dual PHY DS3 modules require compatible releases of the Catalyst 5000 family supervisor engine and ATM PVC traffic-shaping software. Refer to the current release notes applicable to your module for information about software release requirements.

Class of Service

Software releases 50.1 and 51.1 support unspecified bit rate (UBR) and constant bit rate (CBR) CoS. CoS for a PVC is determined by the specified traffic shaping. If you specify the peak cell rate (PCR), the PVC will have a CBR CoS. If no PCR is set, the PVC will have a UBR CoS.

Software releases 11.3 and 12.0 support UBR, CBR, and variable bit rate (VBR). As in software releases 50.1 and 51.1, the CoS is determined by the traffic shaping parameters you specify.

• UBR—CoS assigned to the PVC when you specify no traffic shaping.

• CBR—CoS assigned to the PVC when you specify the PCR.

• VBR—CoS assigned to the PVC when you specify the PCR, sustainable cell rate (SCR), and maximum burst size (MBS).

Note   The MBS should be a value between 2 and 255. If you specify an MBS of 1, the channel is opened with CBR CoS.

Traffic Shaping

Traffic shaping uses queues to constrain data bursts, limit peak data rate, and smooth jitters so that traffic will fit within the promised CoS contract.

Software releases 50.1 and 51.1 support up to ten dynamically created rate queues, and the rate queue assigned to a PVC depends on the PCR you assign to that PVC. When you specify the PCR, the software assigns the PVC to a rate queue that most closely matches that cell rate. If you do not specify the PCR, the software automatically assigns the PVC a service class of UBR and the default rate queue, which is the highest bandwidth rate queue available. See Table 4-1 for rate queue ranges in the different
software releases.

Note   Releases 50.1 and 51.1 allow only PCR.

As in releases 50.1 and 51.1, in software releases 11.3WA4 and 12.0W5 rate queues are determined by the traffic shaping you specify. In software releases 11.3 and 12.0, the number of available rate queues is determined by the maximum amount of bandwidth divided by the specified PCR allocated for each PVC. As a result, software release 12.0 provides more rate-queue granularity and makes better use of the available bandwidth. See Table 4-1 for a listing of maximum available bandwidth for specific modules and software versions.

In software versions 11.3WA4 and12.0W5, you can specify PCR, SCR, and MBS traffic-shaping parameters.

The minimum PCR or SCR is 64 Kbps. If you specify a value less than 64 Kbps, the rate specified to the segmentation and reassembly sublayer (SAR) is 64 Kbps.

VTP is disabled by default on the ATM modules, even if you have enabled it to run on the supervisor engine module. If you enable VLAN Trunk Protocol (VTP) in the ATM module, the ATM module creates LAN Emulation Clients (LECs) for each VLAN configured on the supervisor engine. However, because a VLAN cannot simultaneously have LANE and PVCs configured, enabling VTP will cause any previously configured PVCs to be deleted.

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Note   If you want to use PVCs to connect VLANs to the ATM cloud, do not enable VTP on the ATM module. VTP will override PVC configurations.

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PVC Traffic-Shaping Example

Figure 4-1 shows two Catalyst 5000 family switches with ATM dual PHY DS3 modules in a redundant configuration running ATM PVC traffic-shaping software. The ATM dual PHY DS3 modules contain ten rate queues. Twenty-four PVCs are divided among the ten rate queues; each specifies a particular cell rate for the PVC set attached to it. In this example, PVC 1 through PVC 7 are in VLAN 1, PVC 8 through PVC 20 are in VLAN 2, and PVC 21 through PVC 24 are in VLAN 3.

Default PVC Configuration

Table 4-2 shows the default PVC configuration.

Configuring PVC-Supported VLANs

These sections describe how to configure PVC-supported VLANs on the Catalyst 5000 or 6000 family ATM modules:

• Setting Up PVCs in the ATM Cloud

• Configuring a PVC-Supported VLAN

• Configuring a PVC-Supported VLAN with Traffic Shaping

• Unbinding or Removing PVCs from a VLAN

Setting Up PVCs in the ATM Cloud

To configure a PVC within the ATM cloud, refer to the documentation from your ATM switch vendor.

Configuring a PVC-Supported VLAN

To set up a PVC-supported VLAN on the ATM module, perform this task in privileged mode:

	Task	Command
Step 1	On the Catalyst 5000 or 6000 family switch, assign an Ethernet port to the desired VLAN.	set vlan vlan_num mod_num/port_num
Step 2	Establish a connection to the ATM module.	session mod_num
Step 3	Activate privileged mode on the ATM module.	enable
Step 4	Enter configuration mode.	configure terminal
Step 5	Select the ATM interface.	interface atm0
Step 6	Set up the PVCs.	atm pvc vcd vpi vci aal5snap
Step 7	Bind the PVCs to the VLAN.	atm bind pvc vlan vcd vlan_num
Step 8	(Optional) Set up other PVCs for the same VLAN if needed by repeating Steps 6 and 7.
Step 9	Exit configuration mode.	Ctrl-Z
Step 10	Verify the PVC configuration.	show atm vlan show atm vc
Step 11	Save the configuration.	write memory

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Note   Traffic cannot be bridged between ports in the same VLAN if these ports are configured for PVCs.

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Configuring a PVC-Supported VLAN with Traffic Shaping

Note   Traffic shaping requires software release 50.1 or release 51.1.

To configure a PVC-supported VLAN with ATM PVC traffic shaping, perform this task in privileged mode:

Note   The atm bind pvc vlan vcd vlanid command is valid only for the current software release. The atm traffic-shape rate command is not available in software releases 50.1 or 51.1.

Unbinding or Removing PVCs from a VLAN

You can unbind and remove a previously assigned PVC from a VLAN. You can also unbind a previously assigned PVC from a VLAN without removing the PVC. If you do not remove the PVC, you can bind the PVC to a different VLAN.

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Note   The procedures in this section apply to ATM software release 4.1 and ATM PVC traffic-shaping software release 50.1.

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To remove a previously assigned PVC from a VLAN, perform this task in privileged mode:

	Task	Command
Step 1	Enter privileged mode on the ATM module.	enable
Step 2	Enter configuration mode.	configure terminal
Step 3	Select the ATM interface.	interface atm0
Step 4	Remove the PVC from the VLAN.	no atm pvc vcd
Step 5	End the session.	Ctrl-Z

To unbind a previously assigned PVC from a VLAN without removing the PVC itself, perform this task in privileged mode:

	Task	Command
Step 1	Activate privileged mode on the ATM module.	enable
Step 2	Enter configuration mode	configure terminal
Step 3	Select the ATM interface.	interface atm0
Step 4	Unbind the PVC from the VLAN.	no atm bind pvc vlan vcd vlan_num
Step 5	End the session.	Ctrl-Z

ATM PVC Traffic-Shaping Configuration Examples

These sections show ATM PVC traffic-shaping configuration examples:

• Nonredundant Configuration Traffic-Shaping Example

• Redundant Configuration Traffic-Shaping Example

Nonredundant Configuration Traffic-Shaping Example

This example configuration describes how to configure a nonredundant PVC-supported VLAN configuration with traffic-shaping. Figure 4-2 shows the network used in this example. Assume that the ATM module in each Catalyst 5000 family switch is in slot 2. This example applies to both the single and dual PHY OC-3 ATM modules and the dual PHY DS3 ATM module.

Table 4-3 shows the VLAN and switch connections, VPIs, VCIs, and traffic rates for the network shown in Figure 4-2.

• Verify that you have software release 50.1 or later.

• Obtain the VLAN number to be configured.

• Obtain the VPI and VCI for each PVC to be configured.

• Note the interface number on the LightStream 1010 ATM switch to which the ATM module is connected. You need this interface number to connect the PVCs across the ATM cloud on the LightStream 1010 switch.

Set up the PVCs within the ATM Cloud.

Note   These procedures apply only if your ATM switch is a Cisco LightStream 1010 ATM switch. If you have a different ATM switch, consult the documentation provided by the switch vendor.

Step 2   Verify the setup of PVC 1. Enter this command on the LightStream 1010 ATM switch:

Step 3   Create PVC 2 within the ATM cloud. Enter these commands on the LightStream 1010 ATM switch:

Step 4   Verify the setup of PVC 2. Enter this command on the LightStream 1010 ATM switch:

Step 5   Create PVC 3 within the ATM cloud. Enter these commands on the LightStream 1010 ATM switch:

Step 6   Verify the setup of PVC 3. Enter this command on the LightStream 1010 ATM switch:

Set up PVC 1 and PVC 3 on the Catalyst 5000 family Switch 1.

Step 7   At the console of the Catalyst 5000 family Switch 1, establish a connection to the ATM module in
slot 2 by entering these commands:

Step 8   Configure PVC 1 and PVC 3 on Switch 1 by entering these commands:

You can perform all PVC-related configurations for all VLANs on atm0, the major interface, because the subinterface number has no significance for PVC-supported VLANs. VCDs 10 and 11 (used above) can be any unused VCDs. Enter the show atm vc command to find unused VCDs.

Step 9   Bind PVC 1 and PVC 3 to VLAN 5 on Switch 1 by entering these commands:

Enter the VCD numbers used in Step 8. The last option in the atm bind pvc command specifies
VLAN 5.

Step 10   Verify the setup on Switch 1 by entering these commands:

Step 11   Save the configuration as follows:

Set up PVC 1 and PVC 2 on the Catalyst 5000 family Switch 2.

Step 12   At the console of the Catalyst 5000 family Switch 2, establish a connection to the ATM module in
slot 2 by entering these commands:

Step 13   Configure PVC 1 and PVC 2 on Switch 2 by entering these commands:

You can perform all PVC-related configurations for all VLANs on atm0, the major interface, because the subinterface number has no significance for PVC-supported VLANs. VCDs 10 and 11 (used above) can be any unused VCDs. Enter the show atm vc command to find unused VCDs.

Step 14   Bind PVC 1 and PVC 2 to VLAN 5 on Switch 2 by entering these commands:

Enter the VCDs used in Step 13. The last option in the atm bind pvc command specifies VLAN 5.

Step 15   Verify the setup on Switch 2 by entering these commands:

Step 16   Save the configuration as follows:

Set up PVC 2 and PVC 3 on the Catalyst 5000 family Switch 3.

Step 17   At the console of the Catalyst 5000 family Switch 3, establish a connection to the ATM module in
slot 2 by entering these commands:

Step 18   Configure PVC 2 and PVC 3 on Switch 3 by entering these commands:

You can perform all PVC-related configurations for all VLANs on atm0, the major interface, because the subinterface number has no significance for PVC-supported VLANs. VCDs 10 and 11 (used above) can be any unused VCDs. Enter the show atm vc command to find unused VCDs.

Step 19   Bind PVC 2 and PVC 3 to VLAN 5 on Switch 3 by entering these commands:

Enter the VCDs used in Step 18. The last option in the atm bind pvc command specifies VLAN 5.

Step 20   Verify the setup on Switch 3 by entering these commands:

Step 21   Save the configuration as follows:

Redundant Configuration Traffic-Shaping Example

Figure 4-3 shows the PVCs needed for complete redundancy if PHY A or PHY B on either Switch 1 or Switch 2 fails. This example (referred to as example 2) applies to the dual PHY DS3 module, but you can use the same configuration for dual PHY OC-3 modules (with appropriate PCRs).

In Figure 4-3, you see Catalyst 5000 family Switch 1 and Catalyst 5000 family Switch 2, each with an ATM dual PHY DS3 module, connected to a LightStream 1010 ATM switch in the ATM cloud.

Assume PHY A on Switch 1 goes down and transmits no data to PHY A on Switch 2 over PVC 1, even though PHY A on Switch 2 remains active. When PHY A on Switch 1 goes down, PHY B on Switch 1 becomes active and transmits data to PHY B on Switch 2 over PVC 2.

Similarly, if PHY A on Switch 2 goes down and transmits no data to Switch 1 over PVC 1, PHY B on Switch 2 becomes active and transmits data to PHY B on Switch 1 over PVC 3.

Table 4-4 shows the PVCs used to transmit data when the specified PHYs for the Catalyst 5000 family switches in Figure 4-3 are active. For example, if PHY A on Switch 1 and PHY A on Switch 2 are both active, data is transmitted on PVC 1.

Note   To ensure redundancy for data transmission using dual PHYs, you must set up PVCs 1, 2, 3, and 4 on the same VLAN and configure the same data rate for each PVC.

The following assumptions apply for this example configuration:

• Table 4-5 lists the PVC and switch connections, VPI, VCI, and traffic rates shown in Figure 4-3.

• The ATM module is installed in slot 2 of the Catalyst 5000 family switches.

• Any number of PVCs can be bound to the same VLAN. However, to prevent loops, each PVC must uniquely connect a VLAN group between two Catalyst 5000 family switches. You can also enable Spanning Tree Protocol to prevent loops.

Before configuring the VLAN over PVCs, you must perform these tasks:

• Verify that you have ATM module software release 51.1(2) or above.

• Obtain the VLAN number to be configured.

• Obtain the VPI and VCI for each PVC to be configured.

• Note the interface number of the LightStream 1010 ATM switch to which the Catalyst 5000 family ATM module is connected. You need this interface number to connect the PVCs across the ATM cloud on the LightStream 1010 ATM switch.

To configure the devices in this example, follow these steps:

Note   These procedures apply only if your ATM switch is a Cisco LightStream 1010 ATM switch. If you have a different ATM switch, consult the publication that accompanied the switch.

Set up the PVCs within the ATM cloud.

Step 2   Verify the setup of PVC 1. Enter this command on the LightStream 1010 ATM switch:

Step 3   Create PVC 2 within the ATM cloud. Enter these commands on the LightStream 1010 ATM switch:

Step 4   Verify the setup of PVC 2. Enter this command on the LightStream 1010 ATM switch:

Step 5   Create PVC 3 within the ATM cloud. Enter these commands on the LightStream 1010 ATM switch:

Step 6   Verify the setup of PVC 3. Enter this command on the LightStream 1010 ATM switch:

Step 7   Create PVC 4 within the ATM cloud. Enter these commands on the LightStream 1010 ATM switch:

Step 8   Verify the setup of PVC 4. Enter this command on the LightStream 1010 ATM switch:

Set up the PVCs on the Catalyst 5000 family Switch 1.

Step 9   At the console of the Catalyst 5000 family Switch 1, session to the ATM module in slot 2 by entering these commands:

Step 10   Configure PVCs 1, 2, 3, and 4 on Switch 1 by entering these commands:

You can perform all PVC-related configurations for all VLANs on atm0, the major interface, because the subinterface number has no significance for PVC-supported VLANs. VCDs 10 and 11 (used above) can be any unused VCDs. Enter the show atm vc command to find unused VCDs.

Step 11   Bind the PVCs to VLAN 5 on the Switch 1 by entering these commands:

Enter the VCD numbers used in Step 8. The last option in the atm bind pvc command specifies
VLAN 5.

Step 12   Verify the setup on the Switch 1 by entering these commands:

Step 13   Save the configuration as follows:

Set up the PVCs on the Catalyst 5000 family Switch 2.

Step 14   At the console of the Catalyst 5000 family Switch 2, session to the ATM module in slot 2 by entering these commands:

Step 15   Configure PVCs 1, 2, 3, and 4 on Switch 2 by entering these commands:

You can perform all PVC-related configurations for all VLANs on atm0, the major interface, because the subinterface number has no significance for PVC-supported VLANs. VCDs 10 and 11 (used above) can be any unused VCDs. Enter the show atm vc command to find unused VCDs.

Step 16   Bind the PVCs to VLAN 5 on the Catalyst 5000 family Switch 2 by entering these commands:

Step 17   Verify the setup on the Catalyst 5000 family Switch 2 by entering these commands:

Step 18   Save the configuration as follows:

Posted: Tue Nov 28 00:18:51 PST 2000
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