Cisco XR 12000 Series - Manual (Page 64)

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Cisco XR 12000 Series Router SIP and SPA Hardware Installation Guide
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Chapter 2 Overview: Cisco XR 12000 Series Router Shared Port Adapters
1-Port Channelized STM-4/OC-12 SPA Overview
1-Port Channelized STM-4/OC-12 SPA Interface Specifications
The framer processes incoming and outgoing SONET or SDH frames. The framer operates at
OC-12/STM-4 line rates (622.08 Mbps).
Packet data is transported with a user-configured encapsulation (such as Point-to-Point Protocol [PPP])
and is mapped into the STS-12/STM-4 frame.
The 1-Port Channelized STM-4/OC-12 SPA interface is compliant with RFC 1619, PPP over
SONET/SDH, and RFC 1662, PPP in HDLC-like Framing. The 1-Port Channelized STM-4/OC-12 SPA
also provides support for SNMP v1 agent (RFC 1155–1157), and Management Information Base (MIB)
II (RFC 1213).
Note For Cisco IOS XR Software Release 3.8.0 and beyond, the 1-Port Channelized STM-4/OC-12 SPA
supports Frame Relay Fragmentation (FRF.12) to achieve fragmentation of data packets and interleaving
of voice packets. FRF.12 provides a method to fragment low-priority packets and interleave high-priority
packets in between the low-priority fragments to provide less delay or jitter for high-priority traffic like
voice and video.
Note For Cisco IOS XR Software Release 3.8.0 and beyond, the 1-Port Channelized STM-4/OC-12 SPA
supports Multilink Frame Relay (MFR) feature. MFR provides a mechanism for aggregating multiple
serial links into a bundle to provide greater bandwidth, load balancing between links, and improved
service availability by protecting against single point link failures.
1-Port Channelized STM-4/OC-12 SPA Cables and Connectors
The 1-Port Channelized STM-4/OC-12 SPA uses a small form-factor pluggable (SFP) optical transceiver
module installed in each port for SONET and SDH single-mode and multimode optical fiber connection
(see
Figure 2-21 ).
Figure 2-21 SFP Optics Module
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