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This soft copy for use by IBM employees only.
Chapter 5. 8285 ATM Network Specifications
This chapter gives ATM connections and Traffic management specifications
supported by the 8285.
5.1 ATM Connections
The IBM 8285 provides support for the following types of connections:
•
Permanent Virtual Connection (PVC)
Two types of PVCs are supported:
− PVC for virtual channel connections (VCC)
− PVC for virtual path connection (VPC), also known as permanent virtual
path (PVP)
•
Permanent Virtual Path (PVP)
Note that PVPs are not supported when they span over NNI links. However,
PVPs are supported over SSI links.
•
Switched Virtual Connection (SVC)
Note: Switched virtual path (SVP) is not supported by the IBM 8285.
5.1.1 Supported VPI and VCI Range
The virtual path identifiers (VPIs) and virtual channel identifiers (VCIs) supported
by the 8285 are depending the control point version.
Version 1.3:
For the 25 Mbps port:
•
VPIs are in the range 0-3.
•
VCIs are in the range of 32-1023.
For the other ports:
•
VPIs are in the range 0-15.
•
VCIs are in the range of 32-1023.
Note that certain workstation adapters have limited addressing capability as far
as the supported VPIs and VCIs are concerned. These limitations are based on
the number of bits in the ATM header that are recognizable by the workstation
adapter and are defined in the ILMI packets exchanged by the adapter. The 8285
dynamically adjusts the supported VPI and VCI range on a port to the capability
of the attached workstation at the ILMI exchange.
Version 1.4:
For the 25 Mbps ports:
One of the following three modes (ranges) can be selected:
•
VPI/VCI: 0 bit/12 bits (VPI=0, VCI=0 through 4095)
•
VPI/VCI: 2 bits/10 bits (VPI=0 through 3, VCI=0 through 1023)
•
VPI/VCI: 4 bits/8 bits (VPI=0 through 15, VCI=0 through 2556)
Copyright IBM Corp. 1996 81