Cisco Cisco 7600 2-Port OC-12c STM-4c ATM Optical Services Module 数据表
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RFC 1483 Routed and Bridged AAL5 PDUs
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UNI 3.x, 4.0
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ILMI 1.0
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OAM (F4 and F5)
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Per-VP shaping
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Per-VC shaping
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Per-VC L3 queuing
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L3 traffic shaping
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L3 QoS—CBWFQ, LLQ
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L3 Multicast Point-to-Point
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L3 Multicast Point-to-Multipoint
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MTU: 9180 per RFC2225/RFC1577
Per-VC and Per-VP Traffic Shaping
Traffic shaping is typically provided on ATM edge devices to ensure that bursty traffic conforms to a predetermined "contract." The ATM
OSM supports traffic shaping in hardware, on a per-VC basis or per-VP basis. Depending on the selected ATM service class, the ATM
OSM supports configurable parameters such as: peak cell rate (PCR), sustainable cell rate (SCR), and maximum burst size (MBS). These
parameters can be defined based on the specific bandwidth requirements of an individual VC, as needed for a specific application. To
provide further flexibility, the ATM OSM allows each of these parameters to be set over a wide range of small increments:
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Peak and Sustainable Cell Rate (PCR, SCR): 37k to 299,520k with 1k increments
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Maximum Burst Size (MBS): 1-255 cells
High-Performance Architecture
The ATM OSM is based on an advanced dual-SAR architecture. Each OC12 port has one SAR processor dedicated for transmission and
one for reception. Each SAR supports AAL5 ATM adaptation for high-performance data applications. The ATM OSM also includes a
large amount of buffer memory. Head of Line (HOL) blocking is avoided through a TX credit check mechanism that runs on the PXFcode.
This design ensures that bursty traffic from one VC does not prevent another VC from being serviced.
ORDERING INFORMATION
ATM Layer Connection Management
Operations and management (OAM) cells are used for ATM layer end-to-end link management messages. This ensures that the remote end
of the connection is online. Support is provided for both OAM F4 and F5 flows. During segmentation, the OAM cells have the highest
priority, and are transmitted ahead of other queued data.
ENHANCED TWO PORT OC12 ATM OSM FEATURES
The Enhanced two port OC12 OSM cards will support all of the same features as the Original 7600 OSMs, and will take the Cisco 7600
platform to a higher level of functionality. Some of the major feature differences between the enhanced and the original OSMs include:
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Support for enhanced QoS features, such as WRED
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Support for future software enhancements to deliver either Layer-2 or Layer-3 network aggregation services deployed over a network
architecture based on either IP or MPLS protocols. The Cisco 7600 IR will then be capable of supporting Layer-2 services while
simultaneously supporting Layer-3 services, such as Internet Access or IETF RFC 2547 VPNs.
Table 1.
Enhanced 2-Port OC12 ATM OSM Ordering Information