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This chapter describes how to prepare your site before you install modules in the Catalyst 6000 family switches and is divided into the following sections:
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Warning Before you install, operate, or service the system, read the Site Preparation and Safety Guide. This guide contains important safety information you should know before working with the system. |
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Note This chapter does not contain the instructions to install the Catalyst 6000 family switch chassis. For information on installing the switch chassis, refer to the Catalyst 6000 Family Installation Guide. |
Electrostatic discharge (ESD) damage occurs when electronic boards or components are improperly handled. ESD can result in complete or intermittent failures of electronic components. Refer to the Site Preparation and Safety Guide for instructions on preventing ESD damage.
This section discusses two topics you should consider before installing modules in the Catalyst 6000 family switches:
If wires exceed recommended distances, or if wires pass between buildings, give special consideration to the effect of a lightning strike in your vicinity. The electromagnetic pulse (EMP) caused by lightning or other high-energy phenomena can easily couple enough energy into unshielded conductors to destroy electronic devices. If you have had similar problems in the past, you might want to consult experts in electrical surge suppression and shielding.
Most data centers cannot resolve the infrequent but potentially catastrophic problems just described without pulse meters and other special equipment. These problems can cost a great deal of time to identify and resolve, so take precautions by providing a properly grounded and shielded environment, paying special attention to issues of electrical surge suppression.
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Note Refer to the Site Preparation and Safety Guide for more information on electromagnetic interference. |
The length of your networks and the distances between connections depend on the type of signal, the signal speed, and the transmission media (the type of cabling used to transmit the signals). For example, fiber-optic cable has a greater channel capacity than twisted-pair cabling. The distance and rate limits in this chapter are the IEEE-recommended maximum speeds and distances for signaling. However, if you understand the electrical problems that may arise and can compensate for them, you should get good results with rates and distances greater than those described here, although you do so at your own risk.
When preparing your site for network connections to the modules, you need to consider two factors for each type of interface:
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Note See "Cable Specifications," for connector pinouts for the modules. |
The maximum distances for ATM fiber-optic network connections are determined by the transmitter output power, receiver sensitivity, and type of optical source. Table 2-1 lists the maximum transmission distances for multimode fiber (MMF). Table 2-2 lists the optical specifications for single-mode fiber (SMF) cables.
| Characteristic | Specification |
|---|---|
Optical source | LED |
Wavelength | 1300 nm |
Transmitter output power | -19 to -14 dBm |
Receiver sensitivity | -26 to -14 dBm |
Maximum cabling distance | 1640 ft (500 m) |
| Characteristic | Specification |
|---|---|
Optical source | Laser |
Wavelength | 1300 nm |
Transmitter output power | -15 to -8 dBm |
Receiver sensitivity | -28 to -8 dBm |
Maximum cabling distance | 9.3 miles (15 km) |
Table 2-3 lists the IEEE maximum transmission distances for Ethernet and Fast Ethernet.
| Transceiver Speed | Cable Type | Duplex Mode | Maximum Distance Between Stations |
|---|---|---|---|
10 Mbps | Category 3 UTP | Full and half | 328 ft (100 m) |
10 Mbps | Multimode fiber | Full and half | 1.2 miles (2 km) |
100 Mbps | Full and half | 328 ft (100 m) | |
100 Mbps | Full | 6.2 miles (10 km) | |
100 Mbps | Multimode fiber Single-mode fiber | Half | 1312 ft (400 m) |
Table 2-4 provides cabling specifications for the 1000BaseX interfaces, including the Gigabit Ethernet switching modules and the supervisor engine Gigabit Ethernet uplink ports. All Gigabit Ethernet Gigabit Interface Converter (GBIC) interfaces have SC-type connectors, and the minimum cable distance for all GBICs listed (MMF and SMF) is 6.5 feet (2 meters).
| GBIC | Wavelength (nm) | Fiber Type | Core Size (micron) | Modal Bandwidth (MHz km) | Cable Distance |
|---|---|---|---|---|---|
SX1 | 850 | MMF
| 62.5 62.5 50.0 50.0 | 160 200 400 500 | 722 ft (220 m) 902 ft (275 m) 1640 ft (500 m) 1804 ft (550 m) |
LX/LH | 1300 | MMF2
SMF (LX/LH) | 62.5 50.0 50.0
9/10 | 500 400 500
- | 1804 ft (550 m) 1804 ft (550 m) 1804 ft (550 m)
6.2 miles (10 km) |
ZX3 | 1550 | SMF SMF4 | 9/10 8 | - - | 43.5 miles (70 km)5 62.1 miles (100 km) |
| 1MMF only. 2Patch cord required (see the "Patch Cord" section for details). 3You can have a maximum of 12 1000BaseZX GBICs per system to comply with EN55022 Class B and 24 1000BaseZX GBICs per system to comply with FCC Class A. 4Dispersion-shifted single-mode fiber-optic cable. 5The minimum link distance for ZX GBICs is 6.2 miles (10 km) with an 8-dB attenuator installed at each end of the link. Without attenuators, the minimum link distance is 24.9 miles (40 km). |
When using the long wavelength/long haul (LX/LH) GBIC with 62.5-micron diameter MMF, you must install a mode-conditioning patch cord (Cisco product no. CAB-GELX-625 or equivalent) between the GBIC and the MMF cable on both the transmit and receive ends of the link. The patch cord is required for link distances greater than 984 feet (300 meters).
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Note We do not recommend using the LX/LH GBIC and MMF with no patch cord for very short link distances (tens of meters). The result could be an elevated bit error rate (BER). |
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Note The patch cord is required to comply with IEEE standards. IEEE found that link distances could not be met with certain types of fiber-optic cable due to a problem in the center of some fiber-optic cable cores. The solution is to launch light from the laser at a precise offset from the center by using the patch cord. At the output of the patch cord, the LX/LH GBIC complies with the IEEE 802.3z standard for 1000BaseLX. For a detailed description of this problem, see the "Differential Mode Delay" section. |
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Note Cisco Gigabit Ethernet products have been tested and evaluated to comply with the standards listed in "Regulatory Standards Compliance." Equivalent cables should also meet these standards. |
Figure 2-1 shows a typical configuration using the patch cord.
Plug the end of the patch cord labeled "To Equipment" into the GBIC (see Figure 2-2). Plug the end labeled "To Cable Plant" into the patch panel. The patch cord is 9.84 feet (3 meters) long and has duplex SC-type male connectors at each end.
When an unconditioned laser source (LX/LH GBIC) on an SMF cable is directly coupled to an MMF cable, Differential Mode Delay (DMD) might occur. DMD can degrade the modal bandwidth of the fiber-optic cable causing a decrease in the link span (the distance between the transmitter and the receiver) that can be reliably supported.
IEEE 802.3z offers a higher-speed version of Ethernet for backbone and server connectivity using existing deployed MMF cable by defining the use of laser-based optical components to propagate data over MMF cable.
Lasers function at the baud rates and longer distances required for Gigabit Ethernet. 802.3z has identified the DMD condition that occurs with particular combinations of lasers and MMF cable resulting in an additional element of "jitter," which can limit the reach of Gigabit Ethernet over MMF cable.
With DMD, a single laser light pulse excites a few modes equally within an MMF cable. These modes, or light pathways, then follow two or more different paths. These paths may have different lengths and different transmission delays as the light travels through the cable. With DMD, a distinct pulse propagating down the cable no longer remains a distinct pulse or, in extreme cases, may become two independent pulses. Strings of pulses tend to interfere with each other making it difficult to recover data.
DMD does not occur in all deployed fibers; it occurs with certain combinations of worst-case fibers and worst-case transceivers. Gigabit Ethernet is affected due to its very high baud rate and its long MMF cable lengths. SMF cable and copper cable are not affected by DMD.
MMF cable has been tested for use with LED sources only. LEDs can create a condition within a fiber-optic cable referred to as an overfilled launch condition. This condition describes the way LED transmitters couple light into the fiber-optic cable in a broad spread of modes. The generated light shines in multiple directions that overfills the existing cable space and excites a large number of modes (see Figure 2-3).
Lasers launch light in a more concentrated fashion. A laser transmitter couples light into only a fraction of the existing modes or optical pathways present in the fiber-optic cable (see Figure 2-3).
The solution is to condition the laser light launched from the source (transmitter) so it spreads the light evenly across the diameter of the fiber-optic cable making the launch look like an LED source to the cable. The modes of light are scrambled to distribute the power more equally in all modes and prevent the light from being concentrated in just a few modes. This is in contrast to an unconditioned launch, which, in the worst case, might concentrate all of its light in the center of the fiber-optic cable, exciting only two or more modes equally.
A significant variation in the amount of DMD is produced from one MMF cable to the next. No reasonable test can be performed to survey an installed cable plant to assess the effect of DMD. Therefore, you must use the mode-conditioning patch cords for all LX/LH GBICs using MMF when the link span exceeds 984 feet (300 meters).
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Note For link spans less than 984 feet (300 meters), you can omit the patch cord (we do not recommend using the LX/LH GBIC and MMF with no patch cord for very short link distances [tens of meters]. The result could be an elevated bit error rate [BER]). |
This section describes the port cabling specifications for the supervisor engine.
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Note The accessory kit that shipped with your Catalyst 6000 family switch contains the necessary cable and adapters to connect a terminal or modem to the front-panel console port of the supervisor engine. These cables and adapters are the same as those shipped with the Cisco 2500 series routers and other Cisco products. |
The supervisor engine front-panel console port mode switch allows you to connect a terminal or modem to the console port using the cable and adapters provided or you can connect your terminal using a Catalyst 5000 family Supervisor Engine III cable (not provided).
Table 2-5 lists the maximum transmission distances for console port cables.
See Appendix A, "Regulatory Standards Compliance" for console port and cable pinout information.
| Rate (bps) | Distance (feet) | Distance (meters) |
|---|---|---|
2400 | 200 | 60 |
4800 | 100 | 30 |
9600 | 50 | 15 |
19,200 | 25 | 7.6 |
38,400 | 12 | 3.7 |
56,000 | 8.6 | 2.6 |
This section describes the connector types you need to cable to the switching ports.
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Note You can have a maximum of 12 1000BaseZX GBICs per system to comply with EN55022 Class B and 24 1000BaseZX GBICs per system to comply with FCC Class A. |
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Note When you plug the SC-type connector into the GBIC, make sure that both the Tx and Rx fiber-optic cables are fully inserted into the SC-type connector. |
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Note If you are using the LX/LH GBIC with MMF, you need to install a patch cord between the GBIC and the MMF cable. See the "Patch Cord" section for details. |
Posted: Wed Jun 28 09:47:51 PDT 2000
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