What is the Virtual Path Identifier/Virtual Channel Identifier (VPI/VCI) range for the IMA cards?
A. In order to address multiple physical interfaces and IMA groups, a VPI translation logic has been added. This logic holds VPI ranges as defined in bits 5 and 6 for internal processing. The logic adds and subtracts VPI bits to properly map the logical connection between the physical interface or IMA group and the Virtual Channel (VC) being used by the Segmentation and Reassembly (SAR) function. The original implementation provided 4 bits for the VPI range. CSCdt64050 provides information about address expansion of the VPI range to 8 bits while substituting 0s for bits 5 and 6 with omission of the vp-per-vc command. With bits 5 and 6 being substituted for 0, the useable VPI values are 0-15, 64-79, 128-143, and 192-207. If you try to configure VPI/VCI values outside this range, you will get the message shown below: 3640-2.2(config)#int atm0/0.100 3640-2.2(config-subif)#pvc 16/35 %Invalid VPI of 16 requested: (ATM0/0): Not creating vc:1 Legal VPI sub-ranges are 0-15, 64-79, 128-143, 192
