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VPI/VCI Address Ranges

The VPI/VCI address ranges allowed on ATM interfaces are module dependent. Certain modules on ERX-14xx models, ERX-7xx models, or the ERX-310 router have a fixed allocation scheme, whereas others have a configurable allocation scheme. In the configurable allocation scheme, a bit range is shared across the VPI and VCI fields.

For example, if an ATM interface has a bit range of 18, and 4 bits are allocated to the VPI space, then 14 bits are left for the VCI space. The resulting numeric range is 0 to 2n-1, where n is the number of bits for each space. Completing the example, if 4 bits were allocated for the VPI space and 14 for the VCI space, the configurable range would be 0 to 15 for VPI and 0 to 16,383 for the VCI space. To configure the bit range, use atm vc-per-vp .

See Supported Features for details on how various line module and I/O modules support configurable VPI/VCI address ranges.

Note: The E120 router and the E320 router support the full VPI/VCI address range; therefore, it has a fixed allocation scheme.

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