Zhone Technologies IMACS Network Device - Manual (Page 9)

Zhone Technologies, Inc. IMACS Product Book, Version 4
March 2001 Page 5
Server Buses
The Server buses are all the buses that are accessible by the Server cards. Effectively this is the union of User buses
and WAN bases. This enables the Server cards to provide a data processing function for WAN and User cards. The
Server/Server card typically provides a centralized processing function on data initially entering the system from
User or WAN connections.
A Server/Server card has the same highway interfaces as a CPU card with cross-connect functionality. A Server
card can therefore function as a general cross-connect, or can rely on the cross-connect on the CPU, as needed by
the application. The directions of the highways may be reversed, depending on whether a Server card is interfacing
with User/WAN cards or with another CPU/Server card. For example, when a Server card is interfacing with
User/Wan cards, it will drive the same TDM highways a CPU card normally drives. When interfacing to a CPU
card it will drive the same TDM leads of a highway as a User/WAN card drive. When interfacing to another Server
card, both cards may have to be programmed as to which highway lead to drive on and which to receive on. It may
have to be able to drive and receive on both of the transmit and receive highways on a per time slot basis.
Card Type Summary
The IMACS chassis architecture supports five basic types of cards. They are the Central Processing Unit (CPU)
card, Interface card, Wide Area Network (WAN) card, User card and Server card. Each IMACS system has at least
one CPU and WAN card and one Interface card. These three cards provide common functions for the shelf. The
WAN, User, and Server cards provide the specific data terminal and network interfaces and processing required by
the customer to transfer data from the premise to the network. IMACS architecture has specific card slots, which are
tailored to provide either a WAN, User or Server function.
CPU Card
The CPU is the “brain” of the IMACS and performs most of the configuration, management, and MIB and common
processing for the IMACS. In addition the CPU card provides the interconnection of WAN, User, and Server TDM
buses through a bus connect or cross-connect function. The IMACS can have up to 2 CPU cards, which provide a
redundant control and switching complex. If the primary CPU fails, the standby takes over. A Mini-DACS 1/0
cross-connect for 256 DSOs is available.
Interface Card
The interface card has common hardware, which is managed by the active CPU card. Configuration information
processed on the CPU card is stored in the NVRAM on the interface card. It has interfaces to support a modem,
control terminal, management port, printer, alarm relay, and provides the physical connection to the eight T1/E1
interfaces used by the WAN cards. The card also contains the clock hardware, which provides the entire back plane
timing signals for the PCM buses. One Interface card is required per system.
WAN Card
The WAN cards provide electrical interfaces to high-speed digital facilities, which are connected via the Interface
card. The WAN cards take the voice and data traffic off the TDM bus, which was put there by the User and Server
cards, and transmit the information over a WAN link. A WAN link is typically a T1, CEPT-E1, DSX-1, or HDSL
facility connection. The WAN cards support a 1:N redundancy feature with Cross Connect CPUs only.