Specifications

MGX 8220 Service Modules 4-13

ATM UNI Service Module

The ATM UNI Service Module (AUSM) is a two-card set consisting of an AUSM function module

front card and either a 4 T1 or a 4 E1 line module back card. The E1 line module cards are further

categorized by BNC or DB15 connector type.

Up to 10 AUSMs may be installed in a shelf in slots 5 through 14.

The main function of the AUSM cards is to provide an ATM UNI/NNI interface at T1 or E1 rates so

that ATM UNI user devices can transmit and receive traffic over an ATM BPX 8620 network.

The AUSM supports up to a maximum of 256 connections which can be allocated across 4 T1 or E1

lines in any manner. The connections can be either VPC or VCC as follows:

• VCCs have a VPI value of 0-16 to indicate slot number on the cell bus side.

• VPCs have a VPI value of >16 on the cell bus side.

• User side can have any value of VPI and VCI.

The BNM performs the appropriate header translation and routes cells to the correct slot.

The AUSM has extensive traffic control features. ForeSight feature, providing virtual circuit and

virtual path end-to-end flow control is supported.

The AUSM contains 8000 cell queue buffers for each ingress and egress data flow. The Usage

Parameter Control (UPC) algorithm and the queues are user configurable.

CAC is implemented to support separate% utilization factors, PCRs and MCRs for both ingress and

egress CLI.

An illustration of the AUSM card set is provided in Figure4-8.