Cisco Systems manual Cisco uBR10012 OC-48 DPT/POS Interface Module, Attenuation

Chapter 1 Cisco uBR10012 Universal Broadband Router Overview

Network Uplink Cards

Attenuation

The Cisco uBR10-SRP-OC12SML DPT WAN line card is designed to be used at any distance between 15 and 40 kilometers (km). For short-distance operations (less than 15 km), use a 10 dBm optical attenuator on the link between the two nodes to prevent clipping and oversaturating of the optical receiver. The attenuator should be made of a non metallic or plastic material.

The exact attenuation value is based on the real cable length or the number of couplers and splicers on the link. For example, 5 dBm attenuator could be used in a 7 km link.

Table 1-23	Cable Specification
Fiber Type		Wavelength, nm	Core Size, microns	Cable Distance
Single-mode fiber		1310	8 to 10	49,213 – 131,234 ft.
				(15 – 40 km)

Note The maximum distance of 40 km assumes that the 1310 nm SMF optical cable attenuation is no more than 0.5 dB per kilometer; and that there is no optical coupler or splicer in the link (each could add 0.5 dB loss).

Cisco recommends the use of a SC/PC female to SC/PC male optical attenuator for the

Cisco uBR10-SRP-OC12SML DPT WAN line card.

Tip The SC/PC (Standard Connector/Physical Contact) denotes a connector with a rectangular shape. The surfaces are parallel with respect to the port (not angled). SC/APC (Standard Connector Angled Physical Contact) denotes an angled surface.

Caution Make sure that you obtain the correct connector type (SC/PC) when purchasing optical attenuators. Angled SC/APC type mating surfaces can damage the Cisco uBR10-SRP-OC12SML DPT WAN line card (RX port) interface.

See Optical Connectors and Cables, page 1-47.

Cisco uBR10012 OC-48 DPT/POS Interface Module

The Cisco uBR10012 OC-48 dynamic packet transport (DPT) and packet-over-SONET interface module is a full-height line card for the Cisco uBR10012 universal broadband router. This card provides trunk uplink capabilities that support up to 1.4 Gbps full duplex throughput over a standard SONET/ITU-T Synchronous Digital Hierarchy (SDH) interface, using a single mode fiber with SC connectors.

Two versions of the Cisco uBR10012 OC-48 DPT/POS interface module are available— short reach (SR) or long reach (LR). Both versions work with the performance routing engine (PRE).

The Cisco uBR10012 OC-48 DPT/POS interface module provides a point-to-point connection to a backbone router and encapsulates IP Packets with byte-wise HDLC framing, placing them directly into the OC-48 SONET (or SDH) payload.

	Cisco uBR10012 Universal Broadband Router Hardware Installation Guide
OL-18259-01		1-45