SONET/SDH Optical Interface CardsAll current industry-standard SONET/SDH interface types are available for the ONS 15454 platform, including OC-3/STM-1, OC-12/STM-4, OC-48/STM-16, and OC-192/STM-64. These interface cards are typically distinguished by bandwidth, wavelength, and number of ports; however, with the newer interfaces based on Small Form Factor Pluggable (SFP/XFP) technology, these parameters can vary from port to port on the same interface card. Therefore, we briefly discuss the available card types in terms of two categories: fixed optics interfaces and modular optics interfaces. Fixed optics interfaces are those for which the bandwidth (for example, OC-12/STM-4), the wavelength (for example, 1310 nm), and the number of equipped ports (for example, a four-port OC-12/STM-4 interface card) are predetermined parameters that cannot be field-modified. Table 6-4 gives a listing of these interfaces, including card name, SONET/SDH bandwidth for each port, transmitter wavelength, the number of ports included on the interface card, and the quantity and type of optical fiber connectors on the card's faceplate.
Note Each port has two associated connectors, one for the transmitter and one for the receiver. A card name that includes the IR (and SH) designations indicates a card designed for intermediate-reach (short-haul) applications. A card with the LR/LH designations indicates a long-reach/long-haul card. Similarly, ELR/EH (extended long reach/extended haul) and SR (short reach) are indicative of the card's transmission distance specifications. Modular optics interfaces are those for which the bandwidth, the wavelength, and possibly even the number of equipped ports are parameters that are made flexible through the use of SFPs or XFPs. SFPs and XFPs are essentially electrical-to-optical signal converters that provide a modular interface between a port on an interface card and the external fiber-optic cabling. SFPs and XFPs are similar in design; the primary difference is the module size (XFPs are larger). Modular optics are available for various wavelengths, optical reaches, and technologies, such as SONET/SDH and Gigabit Ethernet (GigE). An SFP or XFP is inserted into the required card port faceplate receptacle and provides a transmit/receive pair of LC fiber connectors. Figure 6-10 shows a group of SFPs, as well as an enlarged view of an SFP connector end. Figure 6-10. SFP Interface Modules
Currently, two SONET/SDH interfaces take advantage of SFP/XFP technology to offer user flexibility and maintenance spare savings:
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