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This manual describes the features and functions of Release 3.0 of the StrataCom ATM Switch Interface Shelf (AXIS), shown in Figure 1-1. Where appropriate, expansion and enhancement capabilities which may be implemented in later releases are indicated.
AXIS is designed on the philosophy that large scale deployment of narrowband and medium-band services is best handled using an ATM infrastructure. In fact, support of these services can, by themselves, cost justify an ATM infrastructure. The same infrastructure can then be used to provide broadband services to customers when and where they are needed.
AXIS is an adjunct shelf to StrataCom's BPX ATM switch. Architecturally it provides:
AXIS is a flexible standards-based service access platform. AXIS can support a wide range of services over narrowband and mid-band user interfaces, mapping all the service traffic to and from ATM, based upon standardized interworking methods. The aggregated traffic is sent/received over an ATM interface to an ATM switch (BPX), using up only a single port on the ATM switch.
Release 3.0 of AXIS supports up to 40 channelized or non-channelized T1 and E1 interfaces on a single shelf providing support for Frame Relay UNI and NNI; ATM UNI, NNI, and FUNI; Frame Relay to ATM network interworking; Frame Relay to ATM service interworking and circuit emulation services. AXIS Release 3 also supports the use of Inverse Multiplexing for ATM (IMA) to provide ATM trunking below T3/E3.
The system's modular, software-based architecture enables it to support these and other additional user services in the future, through downloadable software upgrades or new hardware modules.
Standards-Based Conversion to ATM
All user information received by AXIS 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.
Aggregation of Traffic into ATM Networks
Each AXIS connects to the BPX across a T3 or E3 ATM STI (StrataCom Trunk Interface) to a BNI module on the BPX. Thus, AXIS Release 3.0 supports aggregation of traffic for up to 40 T1 or E1 access ports, or up to 1240 64-Kbps subscribers, onto a single T3 or E3 trunk, using only a single port on the BPX.
In this release, AXIS should normally be co-located with the BPX. In subsequent releases provision is made to allow AXIS to be remoted either in another Central Office or on the customer's premises in a more robust fashion. Figure 1-2 shows how AXIS usage is envisioned in Release 3.0.
Figure 1-2 : AXIS/BPX Relationship
For remote locations with limited bandwidth needs, AXIS can be remoted from the BPX using IMA trunk machines as shown in Figure 1-3.
Figure 1-3 : Remote AXIS Configuration
The following subsections provide an overview of the AXIS shelf, the Release 3.0 cards, and management capabilities. In-depth details are provided in subsequent chapters.
Physically, AXIS consists of cards in a 19" rack mountable shelf.
The shelf can be powered either from a -48V DC source or from a 220V 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 AXIS shelves can be mounted in the same rack, sharing power and cooling assemblies.
AXIS contains 16 slots where each slot can accommodate a front card and a back card. The front row is used for function modules, cards that perform more complex functions within the unit (for example, frame relay to ATM conversion). The back row is used for line modules, cards that provide interfaces to one or more transmission lines connected to AXIS (for example, the trunk line to the BPX or an RS-232 line to a control terminal).
AXIS cards are always installed as a pair consisting of a front card (function module) and a matching back card (line module) in the same slot, except for the SRM-T1E1 card which only has a front card. Communication between slots is achieved through buses in the shelf backplane.
Release 3.0 consists of the following module pairs:
The ASC and the BNM modules must always be present in an AXIS shelf and are referred to as the core modules. AXIS release 3.0 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 upon a malfunction of the active BNM or ASC.
The functions and operation of AXIS are achieved through downloaded firmware. The firmware controls the overall operation of the shelf and responds to configuration and other commands received from a user terminal or workstation. AXIS has a command repertoire of over 60 user commands which are used to configure and display the various operational parameters of the shelf.
The current status and configuration parameters of the AXIS modules are maintained in a Management Information Base (MIB) which is updated by the firmware as changes in status and configuration occur. The MIB can be interrogated using SNMP commands.
Most of the functions of AXIS Release 3.0 can be effected through the graphical user interface provided in SrataView Plus 8.2.
The ASC module includes three ports for user input of management commands. A further means of management access is provided inband over the ATM trunk.
The maintenance port is a simple RS-232 port for direct connection to an alpha-numeric terminal into which the user 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 (via Telnet), TFTP and SNMP protocols for communicating with the AXIS shelf.
This section provides a very brief description of the new AXIS features that have been added since Release 2.x
This manual describes the features, functions, construction and operation of StrataCom AXIS Release 3.0 in the following chapters.
Chapter 2---Common Equipment Description, provides a detailed description of the AXIS shelf, the core cards, slot allocation, power modules and fan assemblies.
Chapter 3---Management of the AXIS Shelf, describes the various facilities provided in AXIS for managing the shelf.
Chapter 4---Service Module Descriptions, provides a detailed description of the AXIS service modules that are available in Release 3.0.
Chapter 5---Service Configuration, covers the configuration of a service module connection.
Chapter 6---Installation and Start-up, covers site preparation, mechanical installation, installing and readying cards, making T3, E3, T1, E1 and power connections and initial start-up of the shelf.
Chapter 7---Upgrading covers details of hardware and firmware upgrades to an AXIS shelf.
Chapter 8---Repair and Replacements, describes maintenance and troubleshooting procedures and covers the replacement of cards, power modules and fan assembly.
Appendices---Three appendices provide details on T1, E1, T3, and E3 and control terminal cabling, the AXIS system specification and the Customer Support facilities that are available from StrataCom. Details of the AXIS Command Line Interface and the formats of all the commands are now in a separate AXIS Command Supplement.
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