Cisco Systems MGX 8220 ATM UNI Service Module

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Cisco MGX 8220 Installation and Configuration
Release 5.0, Part Number 78-6430-03 Rev. D0, November 2003
Chapter ATM UNI Service Module
ATM UNI Service Module
The ATM UNI Service Module (AUSM) is a two-card set co nsisting of an AUSM function module f ront
card and either a four or ei gh t por t T1 or E 1 l ine modu le bac k c ard . T he E 1 li ne mod ule card s a re furth er
categorized by BNC or DB15 connect or t ype.
Up to 10 AUSMs may be insta lle d in a shelf in slots 5 to 1 4.
The main function of the AUSM cards is to provide an ATM UNI/NNI interface at T1 or E1 r at es so
that ATM UNI user devices can transmit and r ece ive tr affic over an ATM BPX 86 20 n et work.
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 o f 0 t o 16 to indicate slot num be r 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 appropri ate header translation and routes c ell s to t he co r re ct s lo t.
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 Parame ter
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 Figure4-9.