Cisco Systems MGX 8230 manual Frame Relay Service Modules, Features Common to All FRSMs

Chapter 2 Module and Service Descriptions

Frame Relay Service Modules

Frame Relay Service Modules

The primary function of the Frame Relay Service Modules (FRSM) is to convert between the Frame Relay formatted data and ATM/AAL5 cell-formatted data. For an individual connection, you can configure network interworking (NIW), service interworking (SIW), ATM-to-Frame Relay UNI (FUNI), or frame forwarding. An FRSM converts the header format and translates the address for:

•Frame Relay port number and DLCI

•ATM-Frame UNI (FUNI) port number and frame address or frame forwarding port

•ATM virtual connection identifier (VPI/VCI)

See Configuring Frame Relay Service, page 6-27for instructions to configure the FRSMs.

This section contains the following information:

•Features Common to All FRSMs, page 2-20.

•Redundancy for Frame Service Modules, page 2-22.

•Connection Types on the FRSM, page 2-22.

•Types of Frame Service Modules, page 2-27.

–FRSMs for T1 and E1 Lines, page 2-27.

–FRSMs for T3 and E3 lines, page 2-32.

–FRSMs for Serial Connections, page 2-38.

Features Common to All FRSMs

This section describes features common to all FRSMs. For features specific to the individual module types, see Types of Frame Service Modules, page 2-27. For information to configure the FRSMs, see Configuring Frame Relay Service, page 6-27.

Data-Link Layer features

•Each logical port on an FRSM independently configurable to run Frame Relay UNI, Frame Relay NNI, ATM FUNI, or frame forwarding.

•7E flags used to delineate frames (with bit stuffing to prevent false flags) and for interframe gaps.

•One flag between frames is considered valid upon receipt.

•Supports configuration of one- or two-flag minimum interframe gap for transmission.

•Valid frame sizes from 5 up to 4510 octets.

Frame Relay features

•Each logical port independently configurable as Frame Relay UNI or Frame Relay NNI.

•Meets ANSI T1.618, using two-octet headers.

•Interpreted CCITT-16 CRC at end of the frame (frame discard if in error).

•Supports ITU-T Q.933 Annex A, ANSI T1.617 Annex D, and LMI local management for semipermanent virtual circuits (both UNI and NNI portions); enhanced LMI provides autoconfiguration of traffic management parameters for attached Cisco routers.

	Cisco MGX 8230 Edge Concentrator Installation and Configuration
2-20	Release 1.1.31, Part Number 78-11215-03 Rev. B0, May 2001