Table of Contents

Configuring Circuit Emulation Services

This chapter describes circuit emulation services (CES) and how to configure the CES T1/E1 port adapters in the Catalyst 8540 MSR, Catalyst 8510 MSR, and LightStream 1010 ATM switch routers. You can use CES T1/E1 port adapters for links that require constant bit rate (CBR) services.

Note   This chapter provides advanced configuration instructions for the Catalyst 8540 MSR, Catalyst 8510 MSR, and LightStream 1010 ATM switch routers. For an overview of CES applications and 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. For hardware installation and cabling instructions, refer to the ATM and Layer 3 Port Adapter and Interface Module Installation Guide.

This chapter includes the following sections:

Overview of CES T1/E1 Interfaces

You can use CES T1/E1 port adapters for links that require CBR services, such as interconnecting PBXs, time-division multiplexers (TDMs), and video conference equipment over campus, public, or private networks.

This section provides an overview of the hardware features and functions supported on the CES T1/E1 port adapters.

Clocking Options

You can configure each interface on the port adapter to support the following clocking options:

Interfaces Supported

The number of CES T1/E1 interfaces you can configure is platform dependent:

Connectors Supported

The CES T1 port adapters support UTP connectors and the CES E1 port adapters support UTP, foil twisted-pair, or 75-ohm BNC connectors. Status and carrier-detect LEDs on each port give quick, visual indications of port status and operation. For detailed network management support, comprehensive statistics gathering and alarm monitoring capabilities are provided.

Functions Supported by CES Modules

The functions supported by a CES module include the following:

Framing Formats and Line Coding Options for CES Modules

The CES modules support the framing formats and line coding options shown in Table 18-1.

Default CES T1/E1 Interface Configuration

The following defaults are assigned to all CES T1/E1 interfaces:

The following defaults are assigned to CES T1 port adapters:

The following defaults are assigned to CES E1 port adapters:

Configuring CES T1/E1 Interfaces

To manually change any of the CES T1/E1 default configuration values, enter the interface cbr global configuration command to specify a CBR interface, as follows:

interface cbr card/subcard/port

To configure the CES T1/E1 interfaces perform the following commands, beginning in global configuration mode:

Examples

The following example shows how to change the default cell delay variation for circuit 0 to 30,000, using the ces circuit command:

Note   You might have to use the shutdown command to shut down the interface before you can modify the circuit. After modifying the circuit, use the no shutdown command to reenable the interface.

The following example shows how to change the default CBR interface framing mode to super frame, using the ces dsx1 framing command:

The following example shows how to change the default CBR interface line build-out length to range from 330 to 440 feet, using the ces dsx1 lbo command:

The following example shows how to change the default CBR interface line code method to binary 8 zero suppression, using the ces dsx1 linecode command:

The following example shows how to change the default CBR interface loopback method to payload, using the ces dsx1 loopback command:

See "Configuring Interfaces," to confirm your interface configuration.

General Guidelines for Creating Soft PVCs for Circuit Emulation Services

You can create either hard permanent virtual channels (PVCs) or soft PVCs for unstructured or structured CES, depending on your particular CES application requirements. The main difference between hard and soft PVCs is rerouting in case of failure, as follows:

This section provides general guidelines for configuring soft PVCs for CES modules. For specific instructions for configuring both hard and soft PVCs, see the following sections:

To configure soft PVCs for either unstructured or structured circuit emulation services, follow these steps:

Step 2   Determine which two ports you want to define as participants in the soft PVC.

Step 3   Decide which of the two ports you want to designate as the destination (or passive) side of the soft PVC.

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Note    This is an arbitrary decision—you can choose either port as the destination end of the circuit. However, you must decide which port is to function in this capacity and proceed accordingly.

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Step 4   Decide whether you want the state of the soft PVC to match the state of the ports.

Step 5   Configure the destination (passive) side of the soft PVC. You must configure the destination end of the soft PVC first, as this end defines a CES-IWF ATM address for that circuit.

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Note    If the interface is up, you might have to disable it, using the shutdown command, before you can configure the circuit. After configuring the circuit, use the no shutdown command to reenable the interface.

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Step 6   Retrieve the CES-IWF ATM address of the soft PVC's destination end, using the show ces address command. The following example shows how to display the CES-IWF ATM address and VPI/VCI for a CES circuit:

Step 7   Configure the source (active) end of the soft PVC last, using the information derived from Step 6. You must configure the source end of the soft PVC last, because that end not only defines the configuration information for the source port, but also requires you to enter the CES-IWF ATM address and VPI/VCI values for the destination circuit.

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Note    If the interface is up, you might have to disable it, using the shutdown command, before you can configure the circuit. After configuring the circuit, use the no shutdown command to reenable the interface.

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Step 8   To verify that the CES circuits are up on both sides (source and destination), run the show ces interface command. To verify that the soft PVC was established between two switches, run the show atm vc interface command.

Configuring T1/E1 Unstructured Circuit Emulation Services

This section provides an overview of unstructured (clear channel) circuit emulation services and describes how to configure CES modules for unstructured circuit emulation services.

Overview of Unstructured Circuit Emulation Services

Unstructured circuit emulation services in an ATM switch router network emulate point-to-point connections over T1/E1 leased lines. This service maps the entire bandwidth necessary for a T1/E1 leased line connection across the ATM network, allowing users to interconnect PBXs, TDMs, and video conferencing equipment.

For a detailed description of unstructured circuit emulation services, refer to the Guide to ATM Technology.

The circuit you set up on a CBR port for unstructured service is always identified as circuit 0, because you can establish only one unstructured circuit on any given CBR port. An unstructured circuit uses the entire bandwidth of a T1 port (1.544 Mbps) or an E1 port (2.048 Mbps).

The following subsections describe the procedures for configuring CES modules for unstructured circuit emulation services:

Configuring Network Clocking for Unstructured CES

Circuit emulation services require that the network clock be configured properly. Unstructured services can use synchronous, Synchronous Residual Time Stamp (SRTS), or adaptive clocking mode. For instructions on configuring network clocking, see "Initially Configuring the ATM Switch Router." For a discussion of clocking issues and network examples, refer to the network clock synchronization and network clocking for CES topics in the Guide to ATM Technology.

Configuring Synchronous Clocking With an OC-12c Interface Module

When synchronous clocking is being used and propagated via an OC-12c interface module, be sure to use the following configurations:

Configuring a Hard PVC for Unstructured CES

A CES module converts CBR traffic into ATM cells for propagation through an ATM network. CBR traffic arriving on a CES module port must first be segmented into ATM cells. This cell stream is then directed to an outgoing ATM or CBR port.

Note   As a general rule when configuring a hard PVC, you must interconnect a CBR port and an ATM port in the same ATM switch router chassis.

Figure 18-1 displays unstructured circuit emulation services configured on an ATM switch router, using ATM and CES interface modules to create a hard PVC. In this example, the hard permanent virtual channel (PVC) also uses adaptive clocking, and this CES circuit enables bidirectional, unstructured CBR traffic to flow between these two modules.

To configure a hard PVC for unstructured CES, follow these steps, beginning in privileged EXEC mode:

Example

The following example shows how to configure the hard PVC for unstructured CES (shown in Figure 18-1):

Verifying a Hard PVC for Unstructured CES

To verify the hard PVC configuration, use the following privileged EXEC commands:

Examples

The following example shows how to display the basic information about the hard PVC shown in Figure 18-1, using the show ces circuit command:

The output from this command verifies the source (CBR 3/0/0) and destination (ATM 0/1/3) port IDs of the hard PVC and indicates that the circuit is up.

The following example shows how to display detailed information about the hard PVC shown in Figure 18-1, using the show ces circuit interface command: