NFX250 Network Cable and Transceiver Planning
Pluggable Transceivers Supported on NFX250 Devices
Uplink module ports on NFX250 devices support SFP and SFP+ transceivers. This topic describes the optical interfaces supported for those transceivers. It also lists the copper interface supported for the SFP transceivers.
We recommend that you use only optical transceivers and optical connectors purchased from Juniper Networks with your Juniper Networks device.
If you face a problem running a Juniper Networks device that uses a third-party optic or cable, the Juniper Networks Technical Assistance Center (JTAC) can help you diagnose the source of the problem. Your JTAC engineer might recommend that you check the third-party optic or cable and potentially replace it with an equivalent Juniper Networks optic or cable that is qualified for the device.
The tables in this topic describe the optical interface support over single-mode fiber-optic (SMF) and multimode fiber-optic (MMF) cables and over the copper interface for SFP transceivers:
Table 1—Optical interface support and copper interface support for Gigabit Ethernet SFP transceivers in NFX250 devices.
Table 2—Optical interface support for Gigabit Ethernet SFP+ transceivers.
Table 1: Optical Interface Support and Copper Interface Support for Gigabit Ethernet SFP Transceivers in NFX250 Devices
Ethernet Standard | Specification | Value | |||
|---|---|---|---|---|---|
1000BASE-T | Model number | EX-SFP-1GE-T | |||
Rate | 10/100/1000 Mbps | ||||
Connector type | RJ-45 | ||||
Transmitter wavelength | – | ||||
Minimum launch power | – | ||||
Maximum launch power | – | ||||
Minimum receiver sensitivity | – | ||||
Maximum input power | – | ||||
Core/Cladding size | – | ||||
Modal bandwidth | – | ||||
Distance | 100 m (328 ft) | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-SX | Model number | EX-SFP-1GE-SX | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Dual | ||||
Transmitter wavelength | 850 nm | ||||
Minimum launch power | –9.5 dBm | ||||
Maximum launch power | –3 dBm | ||||
Minimum receiver sensitivity | –21 dBm | ||||
Maximum input power | 0 dBm | ||||
Fiber type | MMF | ||||
Core/Cladding size | 62.5/125 µm | 62.5/125 µm | 50/125 µm | 50/125 µm | |
Fiber grade | FDDI | OM1 | – | OM2 | |
Modal bandwidth | 160 MHz/km | 200 MHz/km | 400 MHz/km | 500 MHz/km | |
Distance | 220 m (722 ft) | 275 m (902 ft) | 500 m (1640 ft) | 550 m (1804 ft) | |
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-SX-ET | Model number | EX-SFP-1GE-SX-ET | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Dual | ||||
Transmitter wavelength | 850 nm | ||||
Minimum launch power | –9.5 dBm | ||||
Maximum launch power | –3 dBm | ||||
Minimum receiver sensitivity | –21 dBm | ||||
Maximum input power | 0 dBm | ||||
Fiber type | MMF | ||||
Core/Cladding size | 62.5/125 µm | 62.5/125 µm | 50/125 µm | 50/125 µm | |
Fiber grade | FDDI | OM1 | – | OM2 | |
Modal bandwidth | 160 MHz/km | 200 MHz/km | 400 MHz/km | 500 MHz/km | |
Distance | 220 m (722 ft) | 275 m (902 ft) | 500 m (1640 ft) | 550 m (1804 ft) | |
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LX | Model number | EX-SFP-1GE-LX | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Dual | ||||
Transmitter wavelength | 1310 nm | ||||
Minimum launch power | –9.5 dBm | ||||
Maximum launch power | –3 dBm | ||||
Minimum receiver sensitivity | –25 dBm | ||||
Maximum input power | –3 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 µm | ||||
Modal bandwidth | – | ||||
Distance | 10 km (6.2 miles) | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-BX-U | Model number | EX-SFP-GE10KT13R14 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1310 nm | ||||
Receiver wavelength | 1490 nm | ||||
Minimum launch power | –9 dBm | ||||
Maximum launch power | –3 dBm | ||||
Minimum receiver sensitivity | –30 dBm | ||||
Maximum input power | –3 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 µm | ||||
Modal bandwidth | – | ||||
Distance | 10 km (6.2 miles) | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-BX-D | Model number | EX-SFP-GE10KT14R13 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1490 nm | ||||
Receiver wavelength | 1310 nm | ||||
Minimum launch power | –9 dBm | ||||
Maximum launch power | –3 dBm | ||||
Minimum receiver sensitivity | –30 dBm | ||||
Maximum input power | –3 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 µm | ||||
Modal bandwidth | – | ||||
Distance | 10 km (6.2 miles) | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-BX-U | Model number | EX-SFP-GE10KT13R15 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1310 nm | ||||
Receiver wavelength | 1550 nm | ||||
Minimum launch power | –9 dBm | ||||
Maximum launch power | –3 dBm | ||||
Minimum receiver sensitivity | –21 dBm | ||||
Maximum input power | –3 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 µm | ||||
Modal bandwidth | – | ||||
Distance | 10 km (6.2 miles) | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-BX-D | Model number | EX-SFP-GE10KT15R13 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1550 nm | ||||
Receiver wavelength | 1310 nm | ||||
Minimum launch power | –9 dBm | ||||
Maximum launch power | –3 dBm | ||||
Minimum receiver sensitivity | –21 dBm | ||||
Maximum input power | –3 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 µm | ||||
Modal bandwidth | – | ||||
Distance | 10 km (6.2 miles) | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-BX-U | Model number | EX-SFP-GE40KT13R15 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1310 nm | ||||
Receiver wavelength | 1550 nm | ||||
Minimum launch power | –6.5 dBm | ||||
Maximum launch power | 2 dBm | ||||
Minimum receiver sensitivity | –23 dBm | ||||
Maximum input power | –3 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 µm | ||||
Modal bandwidth | – | ||||
Distance | 40 km (24.8 miles) | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-BX-D | Model number | EX-SFP-GE40KT15R13 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1550 nm | ||||
Receiver wavelength | 1310 nm | ||||
Minimum launch power | –6.5 dBm | ||||
Maximum launch power | 2 dBm | ||||
Minimum receiver sensitivity | –23 dBm | ||||
Maximum input power | –3 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 µm | ||||
Modal bandwidth | – | ||||
Distance | 40 km (24.8 miles) | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LX | Model number | EX-SFP-1GE-LX40K | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Double | ||||
Transmitter wavelength | 1310 nm | ||||
Minimum launch power | –14 dBm | ||||
Maximum launch power | –8 dBm | ||||
Minimum receiver sensitivity | –45 dBm | ||||
Maximum input power | –3 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 µm | ||||
Modal bandwidth | – | ||||
Distance | 40 km (24.8 miles) | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LH (or 1000BASE-ZX) | Model number | EX-SFP-1GE-LH | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Dual | ||||
Transmitter wavelength | 1550 nm | ||||
Minimum launch power | –2 dBm | ||||
Maximum launch power | 5 dBm | ||||
Minimum receiver sensitivity | –25 dBm | ||||
Maximum input power | –3 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 µm | ||||
Modal bandwidth | – | ||||
Distance | 70 km (43.5 miles) | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LX | Model number | EX-SFP-GE80KCW1470 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1470 nm | ||||
Minimum launch power | 0 dBm | ||||
Maximum launch power | 5 dBm | ||||
Minimum receiver sensitivity | –32 dBm | ||||
Maximum input power | –8 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 μm | ||||
Modal bandwidth | – | ||||
Distance | 80 km (49.7 miles) | ||||
DOM support | Available | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LX | Model number | EX-SFP-GE80KCW1490 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1490 nm | ||||
Minimum launch power | 0 dBm | ||||
Maximum launch power | 5 dBm | ||||
Minimum receiver sensitivity | –32 dBm | ||||
Maximum input power | –8 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 μm | ||||
Modal bandwidth | – | ||||
Distance | 80 km (49.7 miles) | ||||
DOM support | Available | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LX | Model number | EX-SFP-GE80KCW1510 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1510 nm | ||||
Minimum launch power | 0 dBm | ||||
Maximum launch power | 5 dBm | ||||
Minimum receiver sensitivity | –32 dBm | ||||
Maximum input power | –8 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 μm | ||||
Modal bandwidth | – | ||||
Distance | 80 km (49.7 miles) | ||||
DOM support | Available | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LX | Model number | EX-SFP-GE80KCW1530 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1530 nm | ||||
Minimum launch power | 0 dBm | ||||
Maximum launch power | 5 dBm | ||||
Minimum receiver sensitivity | –32 dBm | ||||
Maximum input power | –8 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 μm | ||||
Modal bandwidth | – | ||||
Distance | 80 km (49.7 miles) | ||||
DOM support | Available | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LX | Model number | EX-SFP-GE80KCW1550 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1550 nm | ||||
Minimum launch power | 0 dBm | ||||
Maximum launch power | 5 dBm | ||||
Minimum receiver sensitivity | –32 dBm | ||||
Maximum input power | –8 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 μm | ||||
Modal bandwidth | – | ||||
Distance | 80 km (49.7 miles) | ||||
DOM support | Available | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LX | Model number | EX-SFP-GE80KCW1570 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1570 nm | ||||
Minimum launch power | 0 dBm | ||||
Maximum launch power | 5 dBm | ||||
Minimum receiver sensitivity | –32 dBm | ||||
Maximum input power | –8 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 μm | ||||
Modal bandwidth | – | ||||
Distance | 80 km (49.7 miles) | ||||
DOM support | Available | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LX | Model number | EX-SFP-GE80KCW1590 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1590 nm | ||||
Minimum launch power | 0 dBm | ||||
Maximum launch power | 5 dBm | ||||
Minimum receiver sensitivity | –32 dBm | ||||
Maximum input power | –8 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 μm | ||||
Modal bandwidth | – | ||||
Distance | 80 km (49.7 miles) | ||||
DOM support | Available | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
1000BASE-LX | Model number | EX-SFP-GE80KCW1610 | |||
Rate | 1000 Mbps | ||||
Connector type | LC | ||||
Fiber count | Single | ||||
Transmitter wavelength | 1610 nm | ||||
Minimum launch power | 0 dBm | ||||
Maximum launch power | 5 dBm | ||||
Minimum receiver sensitivity | –32 dBm | ||||
Maximum input power | –8 dBm | ||||
Fiber type | SMF | ||||
Core/Cladding size | 9/125 μm | ||||
Modal bandwidth | – | ||||
Distance | 80 km (49.7 miles) | ||||
DOM support | Available | ||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | ||||
Support for Virtual Chassis configuration | Yes | ||||
Table 2: Optical Interface Support for Gigabit Ethernet SFP+ Transceivers in NFX250 Devices
Ethernet Standard | Specification | Value | ||||
|---|---|---|---|---|---|---|
10GBASE-USR | Model number | EX-SFP-10GE-USR | ||||
Rate | 10 Gbps | |||||
Connector type | LC | |||||
Fiber count | Dual | |||||
Transmitter wavelength | 850 nm | |||||
Minimum launch power | –7.3 dBm | |||||
Maximum launch power | –1.3 dBm | |||||
Minimum receiver sensitivity | –11.1 dBm | |||||
Maximum input power | –1.0 dBm | |||||
Fiber type | MMF | |||||
Core/Cladding size | 62.5/125 µm | 50/125 µm | 50/125 µm | |||
Fiber grade | OM1 | OM3 | OM3 | |||
Modal bandwidth | 200 MHz/km | 500 MHz/km | 1500 MHz/km | |||
Distance | 10 m (32.8 ft) | 30 m (98.4 ft) | 100 m (328 ft) | |||
DOM support | Available | |||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | |||||
Support for Virtual Chassis configuration | Yes | |||||
10GBASE-SR | Model number | EX-SFP-10GE-SR | ||||
Rate | 10 Gbps | |||||
Connector type | LC | |||||
Fiber count | Dual | |||||
Transmitter wavelength | 850 nm | |||||
Minimum launch power | –7.3 dBm | |||||
Maximum launch power | –1 dBm | |||||
Minimum receiver sensitivity | –9.9 dBm | |||||
Maximum input power | –1 dBm | |||||
Fiber type | MMF | |||||
Core/Cladding size | 62.5/125 µm | 62.5/125 µm | 50/125 µm | 50/125 µm | 50/125 µm | |
Fiber grade | FDDI | OM1 | – | OM2 | OM3 | |
Modal bandwidth | 160 MHz/km | 200 MHz/km | 400 MHz/km | 500 MHz/km | 1500 MHz/km | |
Distance | 26 m (85 ft) | 33 m (108 ft) | 66 m (216 ft) | 82 m (269 ft) | 300 m (984 ft) | |
DOM support | Available | |||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | |||||
Support for Virtual Chassis configuration | Yes | |||||
10GBASE-LR | Model number | EX-SFP-10GE-LR | ||||
Rate | 10 Gbps | |||||
Connector type | LC | |||||
Fiber count | Dual | |||||
Transmitter wavelength | 1310 nm | |||||
Minimum launch power | –8.2 dBm | |||||
Maximum launch power | 0.5 dBm | |||||
Minimum receiver sensitivity | –18 dBm | |||||
Maximum input power | 0.5 dBm | |||||
Fiber type | SMF | |||||
Core/Cladding size | 9/125 µm | |||||
Modal bandwidth | – | |||||
Distance | 10 km (6.2 miles) | |||||
DOM support | Available | |||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | |||||
Support for Virtual Chassis configuration | Yes | |||||
10GBASE-ER | Model number | EX-SFP-10GE-ER | ||||
Rate | 10 Gbps | |||||
Connector type | LC | |||||
Fiber count | Dual | |||||
Transmitter wavelength | 1550 nm | |||||
Minimum launch power | –4.7 dBm | |||||
Maximum launch power | 4 dBm | |||||
Minimum receiver sensitivity | –11.3 dBm | |||||
Maximum input power | –1 dBm | |||||
Fiber type | SMF | |||||
Core/Cladding size | 9/125 µm | |||||
Modal bandwidth | – | |||||
Distance | 40 km (24.8 miles) | |||||
DOM support | Available | |||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | |||||
Support for Virtual Chassis configuration | Yes | |||||
10GBASE-ZR | Model number | EX-SFP-10GE-ZR | ||||
Rate | 10 Gbps | |||||
Connector type | LC | |||||
Fiber count | Dual | |||||
Transmitter wavelength | 1550 nm | |||||
Minimum launch power | 0 dBm | |||||
Maximum launch power | 5 dBm | |||||
Minimum receiver sensitivity | –20 dBm | |||||
Maximum input power | –8 dBm | |||||
Fiber type | SMF | |||||
Core/Cladding size | 9/125 µm | |||||
Modal bandwidth | – | |||||
Distance | 80 km (49.7 miles) | |||||
DOM support | Available | |||||
Software required | Junos OS for NFX250 Devices, Release 15.1X53-D40 or later | |||||
Support for Virtual Chassis configuration | Yes | |||||
See also
SFP+ Direct Attach Cables for NFX250 Devices
Small form-factor pluggable plus transceiver (SFP+) direct attach copper (DAC) cables, also known as Twinax cables, are suitable for in-rack connections between servers and switches. They are suitable for short distances of up to 23 ft (7 m), making them ideal for highly cost-effective networking connectivity within a rack and between adjacent racks.
This topic describes:
Cable Specifications
NFX250 devices support SFP+ passive DAC cables. The passive Twinax cable is a straight cable with no active electronic components. NFX250 devices support 1 m, 3 m, and 5 m long SFP+ passive DAC cables.
We recommend that you use only SFP+ DAC cables purchased from Juniper Networks with your Juniper Networks device.
If you face a problem running a Juniper Networks device that uses a third-party optic or cable, the Juniper Networks Technical Assistance Center (JTAC) can help you diagnose the source of the problem. Your JTAC engineer might recommend that you check the third-party optic or cable and potentially replace it with an equivalent Juniper Networks optic or cable that is qualified for the device.
The cables are hot-removable and hot-insertable: You can remove and replace them without powering off the switch or disrupting switch functions. A cable comprises a low-voltage cable assembly that connects directly into two SFP+ ports, one at each end of the cable. The cables use high-performance integrated duplex serial data links for bidirectional communication and are designed for data rates of up to 10 Gbps.
Table 3 describes the cable specifications.
Table 3: SFP+ Direct Attach Copper Cable Specifications
Model Number | Specification | Value |
|---|---|---|
EX-SFP-10GE-DAC-1M | Rate | 10-Gbps full-duplex serial transmission |
Connector type | SFP+ passive Twinax cable assembly | |
Supply voltage | 3.3 V | |
Power consumption (per end) | 0.57 W | |
Storage temperature | –40° C through 85° C | |
Cable type | Twinax | |
Wire AWG | 30 AWG | |
Minimum cable bend radius | 1 in. (2.54 cm) | |
Cable characteristic impedance | 100 ohms | |
Crosstalk between pairs | 2% maximum | |
Time delay | 1.31 nsec/ft | |
Length | 1 m (3.3 ft ) | |
EX-SFP-10GE-DAC-3M | Rate | 10-Gbps full-duplex serial transmission |
Connector type | SFP+ passive Twinax cable assembly | |
Supply voltage | 3.3 V | |
Power consumption (per end) | 0.57 W | |
Storage temperature | –40° C through 85° C | |
Cable type | Twinax | |
Wire AWG | 30 AWG | |
Minimum cable bend radius | 1 in. (2.54 cm) | |
Cable characteristic impedance | 100 ohms | |
Crosstalk between pairs | 2% maximum | |
Time delay | 1.31 nsec/ft | |
Length | 3 m (9.9 ft) | |
EX-SFP-10GE-DAC-5M | Rate | 10-Gbps full-duplex serial transmission |
Connector type | SFP+ passive Twinax cable assembly | |
Supply voltage | 3.3 V | |
Power consumption (per end) | 0.57 W | |
Storage temperature | –40° C through 85° C | |
Cable type | Twinax | |
Wire AWG | 24 AWG | |
Minimum cable bend radius | 1 in. (2.54 cm) | |
Cable characteristic impedance | 100 ohms | |
Crosstalk between pairs | 2% maximum | |
Time delay | 1.31 nsec/ft | |
Length | 5 m (16.4 ft) |
Standards Supported by These Cables
The cables comply with the following standards:
SFP mechanical standard SFF-843—see ftp://ftp.seagate.com/sff/SFF-8431.PDF .
Electrical interface standard SFF-8432—see ftp://ftp.seagate.com/sff/SFF-8432.PDF .
SFP+ Multi-Source Alliance (MSA) standards
See also
Understanding NFX250 Devices Fiber-Optic Cable Signal Loss, Attenuation, and Dispersion
To determine the power budget and power margin needed for fiber-optic connections, you need to understand how signal loss, attenuation, and dispersion affect transmission. The NFX250 devices use various types of network cable, including multimode and single-mode fiber-optic cables.
Signal Loss in Multimode and Single-Mode Fiber-Optic Cables
Multimode fiber is large enough in diameter to allow rays of light to reflect internally (bounce off the walls of the fiber). Interfaces with multimode optics typically use LEDs as light sources. However, LEDs are not coherent light sources. They spray varying wavelengths of light into the multimode fiber, which reflects the light at different angles. Light rays travel in jagged lines through a multimode fiber, causing signal dispersion. When light traveling in the fiber core radiates into the fiber cladding (layers of lower refractive index material in close contact with a core material of higher refractive index), higher-order mode loss occurs. Together, these factors reduce the transmission distance of multimode fiber compared to that of single-mode fiber.
Single-mode fiber is so small in diameter that rays of light reflect internally through one layer only. Interfaces with single-mode optics use lasers as light sources. Lasers generate a single wavelength of light, which travels in a straight line through the single-mode fiber. Compared to multimode fiber, single-mode fiber has a higher bandwidth and can carry signals for longer distances. It is consequently more expensive.
For information about the maximum transmission distance and supported wavelength range for the types of single-mode and multimode fiber-optic cables that are connected to the NFX250 devices, see Pluggable Transceivers Supported on NFX250 Devices. Exceeding the maximum transmission distances can result in significant signal loss, which causes unreliable transmission.
Attenuation and Dispersion in Fiber-Optic Cable
An optical data link functions correctly provided that modulated light reaching the receiver has enough power to be demodulated correctly. Attenuation is the reduction in strength of the light signal during transmission. Passive media components such as cables, cable splices, and connectors cause attenuation. Although attenuation is significantly lower for optical fiber than for other media, it still occurs in both multimode and single-mode transmission. An efficient optical data link must transmit enough light to overcome attenuation.
Dispersion is the spreading of the signal over time. The following two types of dispersion can affect signal transmission through an optical data link:
Chromatic dispersion, which is the spreading of the signal over time caused by the different speeds of light rays.
Modal dispersion, which is the spreading of the signal over time caused by the different propagation modes in the fiber.
For multimode transmission, modal dispersion, rather than chromatic dispersion or attenuation, usually limits the maximum bit rate and link length. For single-mode transmission, modal dispersion is not a factor. However, at higher bit rates and over longer distances, chromatic dispersion limits the maximum link length.
An efficient optical data link must have enough light to exceed the minimum power that the receiver requires to operate within its specifications. In addition, the total dispersion must be within the limits specified for the type of link in Telcordia Technologies document GR-253-CORE (Section 4.3) and International Telecommunications Union (ITU) document G.957.
When chromatic dispersion is at the maximum allowed, its effect can be considered as a power penalty in the power budget. The optical power budget must allow for the sum of component attenuation, power penalties (including those from dispersion), and a safety margin for unexpected losses.
Calculating the Fiber-Optic Cable Power Budget for an NFX250 Device
Calculate the link's power budget when planning fiber-optic cable layout and distances to ensure that fiber-optic connections have sufficient power for correct operation. The power budget is the maximum amount of power the link can transmit. When you calculate the power budget, you use a worst-case analysis to provide a margin of error, even though all the parts of an actual system do not operate at the worst-case levels.
To calculate the worst-case estimate for fiber-optic
cable power budget (PB) for the link:
- Determine values for the link's minimum transmitter power
(
PT) and minimum receiver sensitivity (PR). For example, here, (PT) and (PR) are measured in decibels, and decibels are referenced to 1 milliwatt (dBm).PT= –15 dBmPR= –28 dBmNote See the specifications for your transmitter and receiver to find the minimum transmitter power and minimum receiver sensitivity.
- Calculate the power budget (
P) by subtracting (BPR) from (P):T–15 dBm – (–28 dBm) = 13 dBm
Calculating the Fiber-Optic Cable Power Margin for an NFX250 Device
Calculate the link's power margin when planning fiber-optic
cable layout and distances to ensure that fiber-optic connections
have sufficient signal power to overcome system losses and still satisfy
the minimum input requirements of the receiver for the required performance
level. The power margin (PM ) is the amount of power available after attenuation or link loss
(LL) has been subtracted from the power budget
(PB).
When you calculate the power margin, you use a worst-case analysis
to provide a margin of error, even though all the parts of an actual
system do not operate at worst-case levels. A power margin (PM ) greater than zero indicates
that the power budget is sufficient to operate the receiver and that
it does not exceed the maximum receiver input power. This means the
link will work. A (PM)
that is zero or negative indicates insufficient power to operate the
receiver. See the specification for your receiver to find the maximum
receiver input power.
Before you begin to calculate the power margin:
Calculate the power budget. See Calculating the Fiber-Optic Cable Power Budget for an NFX250 Device.
To calculate the worst-case estimate for the power margin
(PM) for the link:
- Determine the maximum value for link loss (
LL) by adding estimated values for applicable link-loss factors—for example, use the sample values for various factors as provided in Table 4 (here, the link is 2 km long and multimode, and the (PB) is 13 dBm):Table 4: Estimated Values for Factors Causing Link Loss
Link-Loss Factor
Estimated Link-Loss Value
Sample Link Loss (LL) Calculation Values
Higher-order mode losses
Multimode—0.5 dBm
0.5 dBm
Single-mode—None
0 dBm
Modal and chromatic dispersion
Multimode—None, if product of bandwidth and distance is less than 500 MHz/km
0 dBm
Single-mode—None
0 dBm
Connector
0.5 dBm
This example assumes five connectors. Loss for five connectors: 5 (0.5 dBm) = 2.5 dBm.
Splice
0.5 dBm
This example assumes two splices. Loss for two splices: 2 (0.5 dBm) = 1 dBm.
Fiber attenuation
Multimode—1 dBm/km
This example assumes the link is 2 km long. Fiber attenuation for 2 km: 2 km (1 dBm/km) = 2 dBm.
Single-mode—0.5 dBm/km
This example assumes the link is 2 km long. Fiber attenuation for 2 km: 2 km (0.5 dBm/km) = 1 dBm.
Clock Recovery Module (CRM)
1 dBm
1 dBm
Note For information about the actual amount of signal loss caused by equipment and other factors, see your vendor documentation for that equipment.
- Calculate the (
PM) by subtracting (LL) from (PB):PB– LL = PM13 dBm – 0.5 dBm [HOL] – 5 (0.5 dBm) – 2 (0.5 dBm) – 2 km (1.0 dBm/km) – 1 dB [CRM] = PM
13 dBm – 0.5 dBm – 2.5 dBm – 1 dBm – 2 dBm – 1 dBm = PM
PM = 6 dBm
The calculated power margin is greater than zero, indicating that the link has sufficient power for transmission. Also, the power margin value does not exceed the maximum receiver input power. Refer to the specifications for your receiver to find the maximum receiver input power.