BXM T3/E3, 155, and 622 6-23
BXM Functional Description
SABRE
The Scheduling and ABR Engine (SABRE) includes both VS/VD and Foresight dynamic traffic
transfer rate control and other functions:
• ATM Forum Traffic Management 4.0 compliant ABR Virtual Source/Virtual Destination
(VS/VD).
• Terminates ABR flows for VS/VD and Foresight control loops.
• Performs explicit rate (ER) and EFCI tagging if enabled.
• Supports Foresight congestion control and manages the designated service classes on a per VC
basis with OAM processing.
• Supports OAM flows for internal loopback diagnostic self-tests and performance monitoring.
• Provides service queue decisions to the Ingress and Egress Queue Engines for per VC queues for
ABR VCs.
Ingress and Egress Queue Engines
The overall function of the queue engines is to manage the bandwidth of trunks or ports (UNI) via
management of the ingress and egress queues.
In addition to the ABR VS queues, the ingress queues include 15 slot servers, one for each of 14
possible BPX destination slots, plus 1 for multicast operation. Each of the 15 slot servers contains
16 Qbins, supporting 16 classes of service per slot server.
In addition to the ABR VS queues, the egress queues include 32 Virtual Interfaces (VIs). Each of the
32 VIs supports 16 Qbins.
SIMBA
This serial interface and multicast buffer ASIC provides the following:
• ATM cell header translation.
• Directs ATM cells to the Egress Queue Engine with a 2 x OC-12c throughput capacity.
• Implements the multi-cast function in the egress direction, providing up to 4000 multicast
connections.
• Translates standard OAM flows and Foresight cells.
• Optimizes backplane bandwidth by means of a polling mechanism.
ACP Subsystem Processor
The ACP performs the following localized functions:
• Initializes BXM at power up
• Manages local connection databases
• Collects card, port, and connection statistics
• Manages OAM operation
• Controls alarm indicators (active, standby, fail)
All basic configuration data on the card is copied to the battery backup memory (BRAM) on the card
so that in the event of a power outage, the card will retain its main configuration.
