Cisco PA-POS-2OC3, Руководство по установке и настройке

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PA-POS-2OC3 Two-Port Packet-over-SONET Port Adapter Installation and Configuration
OL-3028-06
Chapter 1 Overview
OC-3 Optical Fiber Specifications
Packet data is transported using Point-to-Point Protocol (PPP) and is mapped into the STS-3c/STM-1
frame. The encapsulations used add approximately half the number of bytes of transport overhead as that
involved with ATM using ATM Adaptation Layer 5 (AAL5) and line card control (LCC) Subnetwork
Access Protocol (SNAP) encapsulations.
The PA-POS-2OC3 interface is compliant with RFC 1619, PPP over SONET/SDH , and RFC 1662, PPP
in HDLC-like Framing . The PA-POS-2OC3 supports RFC 1619 PPP-over-SONET/SDH encapsulation,
and provides support for SNMP agent v1 (RFC 1155-1157), and Management Information Base (MIB)
II (RFC 1213).
OC-3 Optical Fiber Specifications
The OC-3 specification for optical fiber transmission defines two types of fiber: single-mode and
multimode. Within the single-mode category, two types of transmission are defined: intermediate reach
and long reach. Within the multimode category, only short reach is available.
Modes can be thought of as bundles of light rays entering the fiber at a particular angle. Single-mode
fiber allows only one mode of light to propagate through the fiber, and multimode fiber allows multiple
modes of light to propagate through the fiber.
Multiple modes of light propagating through the fiber travel different distances depending on the entry
angles, which causes them to arrive at the destination at different times (a phenomenon called
modal
dispersion ); therefore, single-mode fiber is capable of higher bandwidth and greater cable run distances
than multimode fiber. Table 1-1 lists nominal OC-3 optical parameters for single-mode and multimode
optical fiber transmission.
Note If the distance between two connected stations is greater than the maximum distances listed, significant
signal loss can result, making transmission unreliable.
Table 1-1 lists the OC-3 optical parameters.
Table 1-1 OC-3 Optical Parameters
Transceiver
Type
1
1. This table gives nominal OC-3 optical parameters.
Transmit
Power
Maximum Power
to Receiver
2
, dBm
2. This value represents the maximum power to which any receiver can be exposed.
Receiver
Sensitivity, dBm Loss
Budgets, dB
Nominal Distance
Between Stations
Single-mode
3
long reach
3. Complies with Bellcore GR-253-CORE Long Reach Specification (LR-1).
–5 dBm min.
to 0 dBm max.
at 1280–1335 nm
4
4. Nominal wavelength is 1310 nm.
–10 –34 10 to 28 Up to 25 mi (40 km)
Single-mode
5
intermediate reach
5. Complies with Bellcore GR-253-CORE Intermediate Reach Specification (IR-1).
–15 dBm min.
to –8 dBm max.
at 1280–1335 nm
4
–8 –28 0 to 12 Up to 9 mi (15 km)
Multimode
6
short reach
6. Complies with Short-Reach OC-3 Specification SR-OC-3.
–20 dBm min.
to –14 dBm max.
at 1280–1335 nm
4
–8 –30 0 to 7 Up to 1.2 mi (2 km)