Specifications

2-24

Cisco MGX 8230 Edge Concentrator Installation and Configuration

Release 1.1.31, Part Number 78-11215-03 Rev. B0, May 2001

Chapter2 Module and Service Descriptions

Frame Relay Service Modules

Frame Relay–to–ATM Direction

EFCI is always set to 0.

ATM–to–Frame Relay Direction

If the EFCI field in the last ATM cell of a segmented frame received is set, then FECN of the Frame

Relay frame will be set.

PVC Status Management

The management of ATM layer and FR PVC status management can operate independently. The PVC

status from the ATM layer is used when determining the status of the FR PVC. However, no direct

actions of mapping LMI A bit to OAM AIS is performed.

Frame Relay-to-ATM Service Interworking

By specifying “service interworking” as the channel type when adding a Frame Relay PVC to an FRSM,

all PVC data is subject to service interworking translation and mapping in both the Frame

Relay–to–ATM and ATM–to–Frame Relay directions. Figure 2-13 is an illustration of typical SIW

connections.

Figure 2-13 BPX 8600 Series Network with SIW Connections

In Figure 2-13, an MGX 8230 node on the right has three Frame Relay SIW connections terminating on

an FRSM. Three far-end terminations for these connections appear in other parts of Figure 2-13:

• ATM FUNI (framed UNI) port on an FRSM

• ATM UNI port on an RPM

• ATM UNI port on a BPX 8600 series BXM card

In addition to frame-to-cell and DLCI-to-VPI/VCI conversion, SIW maps cell loss priority and

congestion data between the Frame Relay and ATM formats and is FRF.8-compliant. It provides full

support for routed and bridged PDUs, transparent and translation modes, and VP translation.

FRSM

RPM

FR UNI

CPE

T1 or E1

ATM FUNI CPE

ATM UNI CPE

MGX 8850

BPX 8620 network

PVCs

17909

BPX 8620

T3, E3, OC3

ATM-UNI CPE