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This chapter provides an overview of the Cisco Optical Regenerator and includes the following sections:
The Cisco Optical Regenerator is a bidirectional OC-48/STM-16 regenerator that transmits optical signals over the longest distance possible. It supports single-mode long reach optical-fiber transmission when connected to an OC-48 line card that is installed in a Cisco 12000 series Gigabit Switch Router (GSR).
The SONET specification for fiber-optic transmission defines the standard for single-mode fiber. The regenerator provides an end-to-end Internet Protocol (IP) transport for long distances by forwarding SONET/SDH traffic at OC-48 line rates.
The Cisco Optical Regenerator uses only single-mode fiber because signals can travel farthest through single-mode long reach fiber. The maximum distance for single-mode installations of the regenerator is determined by the amount of light loss in the fiber path, as well as by the physical limitation of transmitting optical fiber to optical light over exceptionally long distances. High-quality single-mode fiber with minimal high-quality splices can carry a Cisco Optical Regenerator signal up to 50 miles (80 kilometers (km)). Table 1-1 describes the power budget and signal requirements for each regenerator used in an OC-48 SONET installation.
| Transceiver | Power Budget | Transmit Power | Receive Power | Typical Maximum Distance |
|---|---|---|---|---|
Single-mode | 26 dB | -2.0 to 3.0 dBm1 at 1500 to 1580 nm2 | -28 to -9 dBm | 80 km |
| 1dBm = relative to 1 milliwatt 2nm = nanometer |
When you connect the OC-48 line cards that are installed in two Cisco 12000 series GSRs, without a regenerator, you are limited to a maximum distance of 80 km. See Figure 1-1.
Figure 1-2 shows an OC-48 line card installed in each Cisco 12000 series router, with a regenerator configured between them. Each OC-48 regeneration port connects to an OC-48 line card installed in a Cisco 12000 series GSR. Each OC-48 regeneration port is labeled side 0 Tx and Rx, and side 1 Tx and Rx, which corresponds to SONET/Section Data Communication Channel (SONET/SDCC) interfaces, SDCC0 and SDCC1.
The distance from router A to the regenerator is 80 km (50 miles), and the distance from the regenerator to router B is 80 km, for a maximum distance of up to 160 km (100 miles).
Figure 1-3 shows an OC-48 line cards installed in each Cisco 12000 series GSR with two regenerators configured between them. The distance from router A to the first regenerator is 80 km, the distance from the first regenerator to the second regenerator is 80 km, the distance from the second regenerator to router B is 80 km, for a maximum distance of up to 240 km (150 miles).
By using the Cisco Optical Regenerator in an OC-48 SONET installation, you can significantly extend the separation between any two Cisco 12000 series GSRs, depending on the quality of the fiber-optic cabling. The location and number of splices in the fiber-optic cabling may reduce the maximum allowable distance.
This section provides an overview of the external hardware of the Cisco Optical Regenerator. Figure 1-4 shows the location of the regenerator's ports, interfaces, LEDs, power switch, and AC power connector on the AC-powered version.
Figure 1-5 shows the location of the regenerator's ports, interfaces, LEDs, and DC terminal block on the DC-powered version.
A configured Cisco Optical Regenerator has one AC power supply or one DC power supply. The Regenerator is delivered with the type of power supply that you ordered, installed by the manufacturer. Site requirements for the AC-input and DC-input power supplies differ, depending on the type of required source voltage. The power supply specifications in "Power Guidelines" will help you to plan where to install the Cisco Optical Regenerator. Be sure to plan for close proximity of site components for easy cabling configuration.
The Cisco Optical Regenerator supports 4 types of ports and interfaces (see Table 1-2).
| Name | Type | Purpose | Inband/Out-of-Band |
|---|---|---|---|
Console | Physical port | Local (or remote) Management | Out-of-band |
Ethernet | Physical port | Local or Remote Management | Out-of-band |
OC-48/STM-16 Regeneration | Physical ports | Traffic | N/A |
SDCC | Logical port | Remote Management | Inband |
The OC-48/STM-16 traffic ports begin operation as soon as the Regenerator is powered up. The other ports must be correctly configured before use. For details, see "Configuring the Cisco Optical Regenerator."
The Cisco Optical Regenerator console port provides local access through a console terminal or remote access for a console terminal through a modem. The console port is an asynchronous serial EIA/TIA-232 interface that is compatible with an RJ-45 jack on the front panel. The console port supports flow control.
The Cisco Optical Regenerator has a 10BaseT Ethernet port that operates in half-duplex mode. It supports up to 10 megabits per second (Mbps) transfer rates. The Ethernet port uses an RJ-45 jack on the front panel. This port is used for local or remote management of the Regenerator via an out-of-band management.
There are two pairs of these ports: one for the device to the left (such as a Cisco 12000 GSR router), and one for the device to the right. SONET/SDH traffic flows through these ports which provide access to the regeneration function at the heart of the Cisco Optical Regenerator. Each pair comprises a single transmit (Tx) and a single receive (Rx) connector. The ports use SC connectors on the front panel.
The SDCC interfaces (SDCC0, SDCC1) are logical interfaces within the Cisco Optical Regenerator that provide access to the Data Communications Channel (DCC) in the SONET/SDH Section/Regenerator Section overhead of the OC-48/STM-16 traffic. The DCC uses bytes D1, D2 and D3 to form an in-band 192 kilobits per second (kbps) channel for Operations, Administration and Maintenance (OAM) messages between pieces of section terminating equipment (such as, regenerators and routers) The Regenerator expects its OAM information to be carried within HDLC-encapsulated IP packets.
The DCC acts as a pseudo local access network (LAN) connecting all the Regenerators in a single chain between a pair of routers. All the SDCC interfaces must either be in the same subnet, or each link between a pair of Regenerators must be in a different subnet. There must be IP routing configured between them.
As described previously, SONET/SDH traffic flows through the OC-48/STM-16 Regeneration ports to access the re-timing, re-synchronizing and re-amplification regeneration function. This function is represented within the Regenerator as two uni-directional regeneration controllers, regen 0 and regen 1. Also, they give the SDCC logical interfaces access to the Data Communications Channel in the SONET/SDH overhead. In the SONET world, the regen controllers are known as Section Terminating Equipment, or STEs.
Figure 1-7 shows the relationship between the regen controllers and the OC-48/STM-16 ports.
The two regen controllers default to SONET framing, so they must be configured for SDH framing when used in an SDH network.
Table 1-3 lists the Cisco Optical Regenerator system specifications.
| Description | Specification |
|---|---|
Dimensions (H x W x D) | 1.72 x 17.3 x 11.8 inches, one rack unit (4.37 x 43.94 x 29.97 cm) |
10.3 lbs. | |
Input voltage, AC power supply | 100-240 VAC1 |
-48/-60 VDC3 | |
40-MHz Motorola MPC860 | |
Ethernet 10BaseT (RJ-45) | |
OC-48 SONET/STM16 SDH interface | |
Console port | Asynchronous serial port |
Operating environment | 32-104ºF (0-40ºC) |
-40-185ºF (-40-85ºC) | |
5-95%, noncondensing | |
51 dbA4 at 3 feet (0.914m) |
| 1VAC = volts alternating current 2BTU = British thermal unit 3VDC = volts direct current. 4dbA = decibels Acoustic |
Cisco Optical Regenerator software includes the following components:
Cisco IOS software is used to:
Posted: Fri May 12 11:03:36 PDT 2000
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