Introducing the MGX 8220 Shelf

This section provides a very brief description of the new Cisco MGX 8220 shelf features that were added since Release 4.1.

Frame service module (FRSM-HS2) supports up to two high speed serial (HSSI) interfaces at speeds up to 52 Mbps
Standards-based IMA on the AUSM card
V.35 and X.21 support on the Frame service module (FRSM-HS1)

Cisco MGX 8220 System Overview

The Cisco MGX 8220 Edge Concentrator is a standards-based, carrier-class concentrator that concentrates high volumes of traffic for transport over Frame Relay and ATM backbones. The Cisco MGX 8220 adapts incoming data to 53-byte ATM cells using industry-standard ATM adaptation layers (AALS) for transport over the ATM network. A fully-redundant bus architecture provides 640-Mbps capacity for high throughput and application performance.

This chapter describes the features and functions of Release 5.0 of the Cisco MGX 8220 edge concentrator.

The Cisco MGX 8220 IP+ATM edge concentrator offers a wide range of services in a single, compact aggregation shelf. This enables service providers to build an integrated multiservice network to deliver Frame Relay, ATM, and private line services. By concentrating narrowband traffic over a wide-area ATM network backbone, the Cisco MGX 8220 reduces equipment costs and makes efficient use of trunking resources. This protects a service provider's investment in equipment and allows the rapid deployment of new services as required.

Configuration Examples

The Cisco MGX 8220 edge concentrator can be used to concentrate services for a Cisco BPX 8600 series switch either from a local or remote location. The Cisco MGX 8220 can also be used as a stand alone edge concentrator.

Cisco BPX 8600 Series Switch

When configured as part of a Cisco BPX 8600 series wide-area switch, the Cisco MGX 8220 edge concentrator allows modular scaling of the service node capacity without requiring additional switches. All Cisco MGX 8220 edge concentrator shelves in a service node are logically managed as an integrated part of the service node.

Each Cisco MGX 8220 shelf connects to the Cisco BPX switch across one of the following:

T3 or E3 ATM to a BNI or T3/E3 BXM module
SMF SONET ATM link to a BXM-155-8 port or BXM-155-4 port

Thus, the Cisco MGX 8220 shelf supports aggregation of traffic up to 80 T1 or E1 access ports or up to 1240 64-Kbps subscribers, onto a single T3, E3, or OC-3c trunk, using only a single port on the Cisco BPX switch.

Remote Locations

For locations with limited switching requirements, the Cisco MGX 8220 can be physically remote from the Cisco BPX 8600 series switch using IMA trunk machines as shown in Figure 1-3.

Standalone Cisco MGX 8220 Edge Concentrator

The Cisco MGX 8220 edge concentrator is not limited to attachment to the Cisco BPX 8600 series switch. In standalone operation, the Cisco MGX 8220 trunk can attach to any ATM switch to provide service aggregation.

Service Interfaces

Frame Relay UNI/NNI

56 kbps, nx64 kbps, T1, E1, HSSI, X.21
Frame Relay to ATM network and service internetworking

High-speed Frame Relay
ATM Frame UNI

56 kbps, nx64 kbps, T1, E1, HSSI, X.21

ATM UNI/NNI

T1, E1, nxT1 (IMA), nxE1 (IMA)

Frame forwarding

56 kbps, nx64 kbps, T1, E1, HSSI, X.21

Circuit emulation

T1, E1, nx64 kbps

ISDN switched access
SNA services

SDLC and bisync, DS-0, DS-0A

Physical connectivity is provided through individual HSSI, X.21, T1 or E1 ports, V.35, or through channelized T1/E1 interfaces.

Using the service resource module (SRM), multiple T1 interfaces can be supported on physical T3 lines. Frame based services on T3 and E3 high speed lines are also supported.

The Cisco MGX 8220 shelf also supports the use of inverse multiplexing for ATM (IMA) to provide ATM trunking below T3/E3.

Scalability

The Cisco MGX 8220 edge concentrator aggregates traffic from as many as 80 T1 or E1 ports onto a single port of a multiport broadband trunk card. This high port density maximizes use of the Cisco BPX 8600 series high-capacity switch fabric. Each 9-inch rack-mount shelf supports up to 80 DS-1 or E1 ports, or more than 2000 64-kbps users. The Cisco MGX 8220 edge concentrator has a compact footprint that minimizes the space required within central offices.

Standards-Based Conversion to ATM

All user information received by the Cisco MGX 8220 interfaces is converted into 53-byte ATM cells using standard ATM adaptation layers (AALs) for transport over the ATM backbone network. Cell segmentation and reassembly (SAR) and other adaptation functions are distributed to each interface module to eliminate system bottlenecks. The following AAL standards are used:

AAL1 for circuit emulation services.
AAL5 and FR-SSCS (Frame Relay Service Specific Convergence Sublayer) for Frame Relay
(FR to ATM network interworking).
For Frame Relay to ATM service interworking, both transparent and translation modes are supported to map FR to native ATM AAL5.
AAL5 for Frame forwarding.

Traffic Management

Traffic management is provided by the Cisco MGX 8220 Connection Congestion Management (ACCM) feature. This feature is a virtual source/virtual destination rate-based closed loop feedback scheme between nodes based on ForeSight and the ATM Forum Available Rate specification. Periodically the round trip delay (RTD) of a cell to the far end and back is calculated for each actual connection. The RTD is used to determine how frequently the ForeSight rate adjustment cells are sent to the far end. Based on available bandwidth and current access rate, every few microseconds a ForeSight cell is transmitted to the far end with any rate adjustments that are necessary to make better use of the available bandwidth (rate is adjusted up, down, or fast down). The Cisco MGX 8220 MIB includes rate (MIR, PIR, and QIR) and adjustment (up%, down%, and fast-down%) objects.

ATM Local Management Interface

ATM local management interface (ATM LMI) operates between the Cisco MGX 8220 shelf and the Cisco BPX 8600 series. The ATM LMI is used to communicate change of status of semi-permanent connections. The ATM LMI protocol conforms to the protocol specified in ITU-TS Recommendation Q.2931, Sept. 1994. The ATM LMI also supports optional proprietary extensions to the ATM LMI for the reporting of node information and BNI queue configurations.

The two end points of the ATM LMI signaling are an ATM LMI process in the BCC in the Cisco BPX 8600 series and an ATM LMI process in the ASC in the Cisco MGX 8220 shelf. The ATM LMI PDUs are transported over an AAL5 connection (VPI=3/VCI=31) between the BNI on the Cisco BPX 8600 series side and the BNM on the Cisco MGX 8220 side. The ATM LMI process in the Cisco BPX 8600 series can support ATM LMI connections for up to 16 Cisco MGX 8220 shelves.

The Cisco ATM LMI extension (which must be specifically enabled) uses a node update status message, which is sent (Cisco BPX 8600 to Cisco MGX 8220 shelf or Cisco MGX 8220 shelf to Cisco BPX 8600) whenever a change in node name, node IP address, major alarm status, or minor alarm status occurs. The message can optionally contain Qbin status, thereby allowing Cisco MGX 8220 to configure the BNI port egress queues.

Cisco MGX 8220 Shelf

Physically, the Cisco MGX 8220 shelf consists of cards in a 19-inch rack-mounted shelf.

The shelf can be powered either from a -48V DC source or from a 220-240V AC source. The DC version includes DC power entry modules that can be mounted in the shelf. The AC version requires an external rack-mounted, AC power module. Both versions require a rack-mounted cooling assembly. Multiple Cisco MGX 8220 shelves can be mounted in the same rack sharing power and cooling assemblies. For more information on the shelf and power options, see "Common Equipment Description."

The Cisco MGX 8220 shelf contains 16 slots. Each slot can accommodate a front card and a back card. Six slots are reserved for common equipment modules. The common equipment modules are the core modules required for the system to operate. Service modules (SMs) occupy the other 10 slots and provide communication and transfer capability.

The front row of the shelf is used for function modules. These cards perform the more complex functions within the unit (for example, Frame Relay to ATM conversion).

The back row is used for line modules. These cards provide interfaces to one or more transmission lines connected to the Cisco MGX 8220 shelf (for example, the trunk line to the Cisco BPX switch or an RS-232 line to a control terminal).

The front card communicates with the back card using a backplane. This backplane design allows the function modules to be replaced or upgraded without disturbing the physical cabling.

The "Cisco MGX 8220 Cards" section briefly summarizes the front (function) modules available for use with the Cisco MGX 8220.
"Common Equipment Description," includes a description of core modules.
"MGX 8220 Service Modules," describes the various service modules in detail.

Cisco MGX 8220 Cards

Cisco MGX 8220 cards are installed in pairs consisting of a front card (function module) and a matching back card (line module). These cards are installed in the same numbered slot. Communication between slots is achieved through buses in the shelf backplane.

The ASC and the BNM modules must always be present in an Cisco MGX 8220 shelf and are referred to as the core modules. The Cisco MGX 8220 shelf supports redundant core modules where one ASC/BNM set is an active set and a second ASC/BNM is a standby set. In the event of a malfunction, the standby set automatically takes over as the active set. The SRM is optional. If present, it is part of the core card set, with switchover to the standby set if the active BNM or ASC malfunctions.

SRM-T1/E1 card—This module includes only a front card. See the "Service Resource Modules" section for more information.
Service modules that use the SRM-3T3 distribution bus. See the "AX-SRM-3T3" section for more information.

Cards Supported in the Cisco MGX 8220

Cisco MGX 8220 Shelf Controller (AX-ASC)
AXIS Shelf Controller (ASC) is a pair of cards that provides overall control of the shelf. These cards also provide line interfaces to the maintenance and control ports used for user configuration and shelf management.

Broadband Network Modules

Broadband network module (AX-BNM-T3)
This is a pair of cards that provides a UNI/NNI interface to the attached Cisco BPX switch over a T3 ATM interface.
Broadband network module (AX-BNM-E3)
This is a pair of cards that provides a UNI/NNI interface to the attached Cisco BPX switch over an E3 ATM interface.
Broadband network module (AX-BNM-155)
This is a pair of cards that provides the interface to the attached Cisco BPX switch over a SONET ATM interface.

Frame Service Modules

Frame service module for T1 (AX-FRSM-4T1)
This card provides interfaces for up to four T1 lines, each of which can support one 56 kbps or one nx64 kbps FR-UNI, FR-NNI port, ATM-FUNI, or a Frame forwarding port.
Frame service module for E1 (AX-FRSM-4E1)
This card provides interfaces for up to four E1 lines, each of which can support one 56 kbps or one nx64 kbps FR-UNI, FR-NNI, ATM-FUNI, or Frame forwarding port.
Frame service module for eight T1 ports (AX-FRSM-8T1)
This card provides interfaces for up to eight fractional T1 lines, each of which can support one
56 kbps or one nx64 kbps FR-UNI, FR-NNI port, ATM-FUNI, or a Frame forwarding port. The AX-FRSM-8T1 supports fractional and unchannelized T1 port selection on a per-T1 basis.
Frame service module for eight E1 ports (AX-FRSM-8E1)
This card provides interfaces for up to eight fractional E1 lines, each of which can support one
56 kbps or one nx64 kbps FR-UNI, FR-NNI, ATM-FUNI, or Frame forwarding port. The AX-FRSM-8E1 supports fractional and unchannelized E1 port selection on a per-E1 basis.
Frame service module for eight channelized T1 ports (AX-FRSM-8T1-C)
The FRSM-8T1-C allows full DS0 and nxDS0 channelization of the T1s and E1s, for a maximum of 192 ports per FRSM-8T1-C. Using the FRSM-8T1-C, up to 192 fully channelized T1 lines can be operated simultaneously on the Cisco MGX platform.
Frame service module for eight channelized E1 ports (AX-FRSM-8E1-C)
The FRSM-8E1-C allows full DS0 and nxDS0 channelization of the E1s, for a maximum of 248 ports per FRSM-8E1-C. Using the FRSM-8E1-C, up to 192 fully channelized E1 lines can be operated simultaneously on the Cisco MGX platform.
Frame service module for high speed serial (AX-FRSM-HS1)
The FRSM-HS1 provides four X.21 interfaces for full-duplex communications at up to 10 Mbps. This card also supports the two port HSSI back cards with SCSI-2 connectors.
Frame service module for high speed serial (MGX-FRSM-HS1/B)
The FRSM-HS1/B supports up to four V.35 high speed serial (HSSI) interfaces. This card also supports the two port HSSI back cards with SCSI-2 connectors.
Frame service module for High Speed Serial (MGX-FRSM-HS2)
This card supports up to two high speed serial (HSSI) interfaces at speeds up to 52 Mbps.
Frame Relay access service module (FRASM-8T1)
This card provides interfaces for up to eight T1 lines for the support of IBM SNA networks. Both Binary Synchronous Communications (Bisync) and Synchronous Data Link Control (SDLC) protocols are supported.

ATM UNI Service Modules

ATM UNI service module for T1 (AX-AUSM-4T1)
This card provides interfaces for up to four T1 lines, each of which can support one T1 ATM UNI or ATM NNI.
ATM UNI service module for E1 (AX-AUSM-4E1)
This card provides interfaces for up to four E1 lines, each of which can support one E1 ATM UNI or ATM NNI.
ATM UNI service module for T1 (AX-AUSM-8T1)
This card provides interfaces for up to eight T1 lines, each of which can support one T1 ATM UNI or ATM NNI plus additional support for standards-based IMA.
ATM UNI service module for E1 (AX-AUSM-8E1)
This card provides interfaces for up to eight E1 lines, each of which can support one E1 ATM UNI or ATM NNI plus additional support for standards-based IMA.
ATM UNI service module for T1, Version B (MGX-AUSM-8T1/B)
This card provides interfaces for up to eight T1 lines, each of which can support one T1 ATM UNI or ATM NNI plus additional support for standards-based IMA. Version B adds the capability to extract clocking information from the T1/E1/IMA trunk to feed into the Cisco MGX 8800 system clock. This supports ATM forum-compliant IMA (1.0 spec).
ATM UNI service module for E1, Version B (MGX-AUSM-8E1/B)
This card provides interfaces for up to eight E1 lines, each of which can support one E1 ATM UNI or ATM NNI plus additional support for standards-based IMA. Version B adds the capability to extract clocking information from the T1/E1/IMA trunk to feed into the Cisco MGX 8800 system clock. This supports ATM forum-compliant IMA (1.0 spec).

Inverse Multiplexing for ATM Trunk Modules

Inverse multiplexing for ATM trunk module—T3 to T1 (AX-IMATM-8T1/B)
This card acts as an extension of the Cisco BPX BNI card and permits the Cisco BPX ATM trunk to be used over multiple (up to 8) T1 lines instead of a single T3 line.
Inverse multiplexing for ATM trunk module—E3 to E1 (AX-IMATM-8E1/B)
This card acts as an extension of the Cisco BPX BNI card and permits the Cisco BPX ATM trunk to be used over multiple (up to 8) E1 lines instead of a single E3 line.

Circuit Emulation Service Modules

Circuit emulation service module for T1 (AX-CESM-4T1)
This card provides interfaces for up to four T1 lines, each of which is a 1.544 Mbps unstructured synchronous data stream.
Circuit emulation service module for E1 (AX-CESM-4E1)
This card provides interfaces for up to four E1 lines, each of which is a 2.048 Mbps unstructured synchronous data stream.
Circuit emulation service module for T1 (AX-CESM-8T1)
This card provides interfaces for up to eight T1 lines, each of which is a 1.544 Mbps structured or unstructured synchronous data stream.
Circuit emulation service module for E1 (AX-CESM-8E1)
This card provides interfaces for up to eight E1 lines, each of which is a 2.048 Mbps structured or unstructured synchronous data stream.

Service Resource Modules

Service resource module (AX-SRM-T1E1/B)
The optional SRM-T1E1/B provides three major functions for service modules; bit error rate tester (BERT) of T1 and E1 lines and ports, loops back of individual nx64 channels toward the customer premises equipment (CPE), and 1:N redundancy for the service modules.
Service resource module (MGX-SRM-3T3)
The SRM-3T3 provides three major functions for service modules; bit error rate tester (BERT) of T1 and E1 lines and ports, loops back of individual nx64 channels toward the CPE, and 1:N redundancy for the service modules. The SRM-3T3 provides the additional capability of supporting multiple T1 channels over T3 lines on the SRM and distributing those channels to T1 service modules in the shelf.

Cisco MGX 8220 Management

The functions and operation of the Cisco MGX 8220 shelf are achieved through downloaded firmware. The firmware controls the overall operation of the shelf and responds to configuration commands.

The current status and configuration parameters of the Cisco MGX 8220 modules are maintained in a Management Information Base (MIB). The firmware updates the MIB when changes in status and configuration occur. The MIB can be interrogated using SNMP commands.

Most functions of the Cisco MGX 8220 shelf Release 5.0 can be accessed through the graphical user interface (GUI) of the Cisco WAN Manager (CWM), Release 9.2. CWM is a network and element management system that enables operations, administration, and maintenance of WAN-multiservice networks.

The ASC module includes three ports for user input of management commands. Another means of management access is provided in-band over the ATM trunk.
The maintenance port is a simple RS-232 port for direct connection to an alpha-numeric terminal into which you can type commands through a command-line interface (CLI).
The control port (SLIP protocol only), the LAN (Ethernet) port and the in-band ATM connection all support the CLI (using Telnet), TFTP, and SNMP protocols for communicating with the Cisco MGX 8220 shelf.

Table of Contents

Introducing the Cisco MGX 8220 Shelf

New in Release 5.0