4-2
Cisco MGX 8220 Installation and Configuration
Release 5.0, Part Number 78-6430-03 Rev. D0, November 2003
Chapter
Frame Relay Service Modules (FR SMs)
Frame Relay Service Modules (FRSMs)
The primary function of the FRSM is to convert between the Frame Relay formatted data and
ATM/AAL5 cell-formatted data. There are t wo main types of FRSMs, those f or T1 or E1 lines and those
for high speed serial lines.
All FRSMs include the following features:
•ForeSight closed-loop rate control and per-VC queuing
•Wire-speed performance on all ports
•SVC and multicast support within Cisco service nodes
•Standard and enhanced LMI management interfaces (Annex A and Annex D)
Module-specific features are descr ib ed i n th e se ctions listed below.
•FRSM Connection Types, p ag e 4 - 2
•FRSMs for T1 and E1 lines, page 4-7
•FRSMs for High Speed Serial Lines, page 4-9
•Frame Relay Access Service Module, page 4-11

FRSM Connection Types

FRSMs convert the header format and translate the address for
•Frame Relay port number and DLCI
•ATM-Frame UNI (FUNI) port number and frame ad d re ss o r fram e forwarding port
•ATM Virtual Connection Identifier (VPI/VCI)
This section describes the connection types that can be configured on the FRSM to perform these
functions.
•Frame-Relay-to ATM Network Interworking (NIW), page 4-2
•Frame-Relay-to ATM Service Interworking (SIW), page 4-4
•Frame Forwarding, page 4-6
•Frame-based User-to-Network Interface (FUNI), page 4-6

Frame-Relay-to ATM Network Interworking (NIW)

Frame Relay-to-ATM network interworking (NIW) supports a permanent virtual connection (PVC)
between two Frame Relay users over a Cisco network or a multi-vendor network. The traffic crosses
the network as ATM cells. To specify NIW for a connect ion, add the connection with a ch annel type of
network interworkin g.
Figure4-1 shows a BPX 8620 network with network interworking connections.