Ericsson Redback Networks SmartEdge 1200, Руководство по оборудованию

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ATM OC-12c/STM-4c Intermediate Reach Card
Traffic Card Descriptions 2-3
ATM OC-12c/STM-4c Intermediate Reach Card
The Enhanced ATM OC-12c/STM-4c IR card supports one SONET or SDH SMF port, which operates at
622 Mbps, and can be used either as optical line or optical trunk interfaces. In addition, the Enhanced ATM
OC-12c/STM-4c IR card can be used to support subscriber circuits. Figure 2-1 shows the front panel of the
Enhanced ATM OC-12c/STM-4c IR card.
The card uses two segmentation and reassembly (SAR) devices. The ingress SAR performs the reassembly
function on the incoming ATM cell stream from the physical (PHY) device. The egress SAR performs the
segmentation function to create the corresponding outgoing ATM cell stream.
The hardware provides header error control (HEC) framing for the port. The transmit clock can be derived
either from the active controller card or from the onboard local oscillator.
The second-generation ATM OC-12 card up to 16,000 ATM permanent virtual circuits (PVCs).
The SAR devices also support enhanced queuing and shaping functions for more granular control over
traffic management with two, four, or eight distinct class of service queues for each ATM PVC, and allow
a mix of priority- and class-based queuing for each ATM PVC. These additional capabilities allow the card
to support subscriber circuits. For information about ATM PVC and traffic management support, see the
Ports, Circuits, and Tunnels Configuration Guide for the SmartEdge OS.
Figure 2-1 ATM OC-12c/STM-4c IR Card
Note The Enhanced ATM OC-12c/STM-4c IR card is also referred to as a second-generation ATM
OC-12 card.