Cisco MGX 8200 Series Edge Concentrators

Cisco MGX 8800 Serial FRSMs


Data Sheet

Cisco MGX Serial Frame Service Modules

The Cisco FRSM-HS1 frame service module (FRSM) is designed for use with the MGX 8220 edge concentrator. The FRSM-HS1/B and FRSM-HS2 FRSMs are designed for use with the MGX 8230 and MGX 8250 multiservice gateways, and the MGX 8800 wide-area edge switch. The FRSM-HS1 and FRSM-HS2 FRSMs offer high-speed serial frame service interfaces for the new world of data networking. The serial port FRSMs offer connectivity to HSSI and X.21 equipment, with the flexibility to operate as DTE or DCE. The FRSM-HS1 provides four ports of X.21 frame services on a single, seven-inch function module. Likewise, the FRSM-HS1/B provides four ports of V.35 on a single, seven-inch function module, while the FRSM-HS2 provides two ports of HSSI frame services on a single, seven-inch function module.

The MGX-FRSM-HS1/B provides unchannelized Frame relay service on a maximum of 200 connections across four V.35 or X.21 interfaces. The maximum throughput for the card is 16 Mbps. The maximum rate on one line is 8 Mbps. Without the cost of a T3 or E3 card, the MGX-FRSM-HS1/B provides greater than T1 or E1 speeds on a port as well as a choice of 50 line rates in a range of 48 Kbps-8Mbps.

The FRSM-HS2 provides two HSSI interfaces for full-duplex communications at up to 52 Mbps. Each HSSI line consists of a serial connector, along with three LED indicators for line status. Using the FRSM-HS2, up to 48 HSSI ports can be operated simultaneously on the MGX 8800 wide-area edge switch platform.

Ordering Information


Frame service module, supporting four high-speed X.21 ports and four ports of V.35


Frame service module supporting four high-speed V.35 ports and two ports of HSSI


Frame service module, supporting two high-speed HSSI ports


Four X.21 DB-15 backcard for FRSM-HS1


Two HSSI SCSI-2 backcard for FRSM-HS2


Four port V.35 serial backcard


FRSM cards support multiple HDLC-derivative frame service interfaces, which can be configured on a per-port basis. These service interfaces include the Frame Relay UNI, Frame Relay NNI, ATM FUNI, and frame forwarding—HDL-transparent, providing "channel extension" support for legacy HDLC-based protocols such as Point-to-Point Protocol (PPP).

Traffic is mapped between these service interfaces and the ATM backplane using standards-compliant adaptation. Consistent with Cisco's intelligent quality-of-service (QoS) management features, serial port FRSM cards support per-VC queuing on ingress and multiple class-of-service queues on egress. Together with closed loop congestion control, this provides flexible, per-VC control for connection-based service-level agreements (SLAs).

Serial FRSM cards can be Y-cabled to provide 1:1 hot-standby redundancy of the FRSM.

Frame Relay-to-ATM network interworking and Frame Relay-to-ATM service interworking are both supported on a per-PVC basis.

FRSM cards are supported by standards-based management tools, including SNMP, TFTP (for configuration/statistics collection), and a command-line interface. The Cisco WAN Manager and CiscoView tools also provide full graphical user interface support for connection and equipment management.

With these feature options, customers can independently use either frame- or cell-based interfaces at each site, with independent selection of encapsulation techniques, such as IETF RFC 1490 or 1483, to ensure that the sites communicate.


Card Specific

FRSM-HS1 and FRSM-HS1/B X.21 Interfaces

  • Four X.21 lines

  • DCE/DTE selection on a per-port basis

  • As DCE, clock speeds of 48 Kbps, 56 Kbps, n x 64 Kbps up to 2 Mbps, n x 1.5 Mbps and n x 2 Mbps, up to 10 Mbps, are supported

  • As DTE, obtains clock from line, up to 10 Mbps

  • Supports 200 DLCIs per card

  • Support for per-VC queueing on ingress with closed-loop traffic management

  • Support for two priority levels of egress port queues for data traffic

  • Various DCE/DTE loopbacks

FRSM-HS2 HSSI Interfaces

  • Two HSSI lines

  • DCE/DTE selection on a per-port basis

  • As DCE, clock speeds of n x 1.5 Mbps and n x 2 Mbps, up to 52 Mbps, are supported

  • As DTE, obtains clock from line, up to 52 Mbps

  • Supports 2000 DLCIs per card

  • Support for per-VC queueing on ingress with closed-loop traffic management

  • Support for five classes of service (high-priority, rt-VBR, nrt-VBR, ABR, UBR) for data traffic

  • Various DCE/DTE loopbacks

  • 1:1 redundancy with Y-cabling for FRSM-HS2 cards

All FRSM Serial Cards

All Port Types

  • Transmitter loop-timed to receiver or synchronized to shelf

  • 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 frames sizes are five octets, up to 4510 octets

  • Supports up to 200 (FRSM-HS1) or 2000 (FRSM-HS2) virtual connections per card

Frame Relay

  • Each logical port is 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 semi-permanent virtual circuits (both UNI and NNI portions). Enhanced LMI provides auto-configuration of traffic management parameters for attached Cisco routers

  • Frame Relay-to-ATM network interworking (FRF.5) and Frame Relay-to-ATM service interworking (FRF.8), both transparent and translation modes, configured on a per-permanent virtual circuit (PVC) basis

  • Cisco IOS enhancements to Frame Relay-to-ATM service interworking to allow interworking for a wider range of protocols

  • Standards-based CIR policing and DE tagging/discarding

  • End-to-end ForeSight® rate-based flow-control option to improve trunk utilization and user goodput

  • Capability to extend ForeSight closed-loop congestion management between two Cisco networks across FR-UNI or FR-NNI using ANSI T1.618 consolidated link-layer management (CLLM) messages


  • ATM Forum FUNI mode 1A supported

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

  • AAL5 mapping of user payload to ATM

  • Supports 16 VPI values (15 plus the zero VPI); supports virtual path connections (VPCs) for all non-zero VPI values (up to 15 VPCs)

  • Supports 64 VCI values

  • Supports OAM frame/cell flows

  • Standards-based usage parameter control

  • End-to-end ForeSight rate-based flow-control option

Frame Forwarding

  • No assumptions made on the frame header format

  • Interpreted CCITT-16 CRC at end of frame (with frame dropping on an error)

  • If a connection is set up, all frames are routed to/from that connection; otherwise the frame is discarded

  • No translation/mapping attempted between frame header bits and ATM layer EFCI and DE bits

  • A single set of Frame Relay traffic access parameters (for example, CIR) is configured for the logical port in frame-forwarding mode. All arriving frames are treated as if they arrived without a set DE bit. If the frame is determined to exceed the committed rate (exceeding CIR), the CLP of all cells associated with that frame are set to indicate low priority. If the frame exceeds the total rate allowed for committed and uncommitted traffic, the frame is discarded

  • Available end-to-end ForeSight rate-based flow-control option

General Card Information


  • Per card: Active (green), standby (yellow), fail (red)

  • Per line: Active & OK (green), active & local alarm (red), active and remote alarm (yellow)

Maintenance/Serviceability Features

  • Internal problem isolation loopbacks

  • Hot pluggable


  • 100,000 hours MTBF

Card Size

  • Front cards: 7.25 x 15.83 in.

  • Back cards: 7.0 x 4.125 in.


  • -48 VDC, 35.00W (FRSM-HS1)

  • -48 VDC, 56.56W (FRSM-HS2)

Temperature Range

  • 0-50oC (32o-122oF)

Electrical and Safety Compliance

  • FCC Part 15 Class A

  • CISPR Class A (EN55022)

  • NEBS GR-63-CORE, GR-1089-CORE