Bulk Configuration of VC Ranges Overview

When you create a static ATM 1483 subinterface, you must configure a permanent virtual circuit (PVC), also known as a virtual circuit (VC). The ATM protocol requires one or more VCs over which data traffic is transmitted to higher layers in the protocol stack.

Similarly, dynamic creation of ATM 1483 subinterfaces requires you to configure a range of ATM PVCs on the ATM AAL5 interface and assign a name to this range. Each VC range consists of one or more nonoverlapping VC subranges. A VC subrange is a group of VCs that resides within the virtual path identifier (VPI) and virtual circuit identifier (VCI) ranges you specify.

The process of configuring a VC range for a dynamic ATM 1483 subinterface is referred to as bulk configuration. You create a bulk configuration by issuing the atm bulk-config command. For example, the following commands create an ATM 1483 bulk configuration named myBulkConfig on the specified ATM AAL5 interface.

host1(config)#interface atm 2/0 host1(config-if)#atm bulk-config myBulkConfig vc-range 0 3 101 1100
vc-range 4 7 201 700

In this example, the atm bulk-config command configures a VC range made up of two VC subranges. The first subrange, with VPIs 0–3 and VCIs 101–1100, configures 1000 VCs on each of four VPIs, for a total of 4000 VCs. The second subrange, with VPIs 4–7 and VCIs 201–700, configures 500 VCs on each of four VPIs, for a total of 2000 VCs. The entire myBulkConfig VC range configures a combined total of 6000 VCs.

Note: For information about the maximum number of ATM 1483 bulk configurations supported per router, see JunosE Release Notes, Appendix A, System Maximums.

After you issue the atm bulk-config command, the router provisions all circuits in the specified VC range at the same time. This provisioning can take several seconds, depending on the number of VCs being created. The router does not dynamically create the ATM 1483 subinterface for the circuit until it receives incoming data traffic on the circuit.

After you create a named VC range, you cannot remove the underlying ATM AAL5 interface until you issue the no atm bulk-config command to remove the VC range from that interface.

Note: For information about the maximum number of VCs (sum of the VPI/VCI addresses within all VC subranges) that you can configure with the atm bulk-config command per line module and per chassis, see JunosE Release Notes, Appendix A, System Maximums.

Do not use any reserved VCI values when configuring VCs with the atm bulk-config command. For information about reserved VCIs, see Configuring F4 OAM in Configuring ATM.

This topic describes the following:

Bulk Configuration and CAC Overview

You cannot create a bulk-configured VC range on an ATM interface on which you have configured connection admission control (CAC). Conversely, you cannot configure CAC on an ATM interface on which you have created a bulk-configured VC range.

If you are upgrading to the current JunosE Software release from a lower-numbered release, configurations that use CAC and bulk configuration on the same ATM interface continue to work. However, we recommend that you disable CAC on these ATM interfaces to ensure continued compatibility with future JunosE releases.

For information about how to use the atm cac command to configure CAC, see Setting Optional Parameters in Configuring ATM.

Changing VC Subranges Overview

You can add, remove, modify, merge, disable, and enable VC subranges within an existing bulk-configured VC range. Previously, changes to VC subranges were possible only if you removed the VC range and then configured it again with different subrange values. The ability to make changes to VC subranges without first having to remove the entire VC range avoids potentially disrupting all subscribers on existing dynamic ATM 1483 subinterfaces associated with the deleted VC range. For configuration instructions and examples, see Changing VC Subranges

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