HP StorageWorks 4000/6000/8000 .HP StorageWorks SAN Design Reference Guide, Pa - Page 285

System architecture1 Active signal amplification Description • Includes line amplifiers and attenuators that connect to other devices through fiber optic links • Boosts the signals that are transmitted to and received from peripheral network devices • Using hardware and/or software control loops, monitors power levels to ensure that the operation does not exceed the hardware's power budgets Active protocol handling • Offers protocol-specific capabilities for Fibre Channel, enabling digital TDM and nl optical multiplexing to support multiple channels on each wavelength • Provides network monitoring, digital retiming (to reduce timing jitter), link integrity monitoring, and distance buffering • May require additional and potentially costly transmission hardware when deployed in meshed networks Note: HP Continuous Access products require in-order delivery of data replication Fibre Channel frames. Architectures, products, or protocols that do not guarantee in-order delivery are not supported. 1Active protocol handling and passive protocol handling require different switch port settings. See Table 141 on page 288. WDM system characteristics To help carriers realize the full potential of WDM, HP-supported WDM systems have the following characteristics: • Use the full capacity of the existing dark fiber • Offer component reliability, 24x7 availability, and expandability • Provide optical signal amplification and attenuation to increase the transmitted/received signalto-noise ratio • Provide signal conditioning (that is, the retiming and reshaping of the optical data-carrying signal) for optimization of the bit error rate • Offer channel add/drop capability (the ability to change the number of data channels by adding or dropping optical wavelengths on any network node) • Allow compensation of power levels to facilitate adding or dropping channels • Provide upgradable channel capacity and/or bit rate • Allow interoperability through standards-compliant interfaces such as Fibre Channel, SONET, and ATM • Convert wavelengths at each interface channel before multiplexing with other channels for nl transmission HP coarse wave division multiplexing HP offers CWDM, which is similar to DWDM but is less expensive, less expandable (maximum of eight channels), and covers a shorter distance (up to a maximum of 100 km using the 1 Gb/s or 2 Gb/s CWDM SFP transceivers, and a maximum of 40 km using the 4 Gb/s CWDM SFP transceivers). CWDM allows up to eight 1 Gb/s, 2 Gb/s, or 4 Gb/s channels (or wavelengths) to share a single fiber pair. Each channel uses a different color or wavelength CWDM SFP transceiver. The channels are networked using a variety of wavelength-specific multiplexers/demultiplexers or OADMs that support ring or point-to-point topologies. The 4 Gb/s CWDM solution includes the following components: • A 2-slot chassis for CWDM multiplexer modules SAN Design Reference Guide 285