NOVEMBER 2020
(2) Requires efficient I&M under severe security administration
Data center sites are subject to severe security administration requiring I&M work to be performed during restricted time periods. Performing tests of the various communications standards for Metro DCI requires trained and experienced operators with good knowledge about communications and network I&M.
(3) Requires optical fiber maintenance
Metro DCI network configurations use fast high-capacity optical fibers. In addition to conventional optical loss measurements, fast DCI optical fibers must be evaluated for optical reflections. The IEEE802.3 100GBASE-LR4 and 10GBASE-LR standards specify an optical fiber connector reflection loss of not more than 26 dB. Generally, SPC and UPC fiber connectors have a reflection loss of about 40 dB and 50 dB, respectively, but if the connector end face is contaminated with oil, dust, etc., the optical loss increases due to the increased optical reflections caused by the contamination, resulting in degraded communications quality. Appropriate maintenance at optical fiber I&M is key to preventing communications problems.
Throughput measurement results are calculated for: • Utilization layer, Physical layer, Physical layer excluding preamble, Link layer, Network layer and Data layer • Min./Max./Avg. values Performance (M.2100 type) parameters: ES, SES, ALS, UAT, AVT, EFS Test patterns: PRBS 9, PRBS 11, PRBS 15, PRBS 20, PRBS 23, PRBS 29, PRBS 31, HF test pattern, CRPAT, JTPAT, SPAT, 55 Hex, Fox, 32-bit user programmable User-defined resolution: 1, 2, 5, 10, 15, 30 s, 1, 5, 10, 15, 30 min, 1, 2, 4, 6, 12 h Event log: Major measurement events incl. errors and alarms are logged with 1-second resolution
Optical Fiber
Metro DC
Metro DCI Connections
Optical Fiber Cladding
Oil and Dust Contaminauts
Contaminated Optical Fiber End Face
Data Center ToR/Leaf Level Construction/Maintenance
Top of Rack (TOR) architecture is where the cabling between switch and server stays within a rack. This has the benefit of reducing the overall amount of cabling with the downside of reduced efficiency in the usage of Ethernet switch ports which are limited to within a rack. Following measurements at Data Center (DC) Interconnect I&M are conducted. • BER: BER is one of the basic measurements and includes include Frame Loss and Sequence Error tests. • Latency: Network latency is the time it takes for data or a request to go from the source to the destination. Latency in networks is measured in milliseconds. The closer your latency is to zero, the better. • Throughput: Throughput measures how many packets
Moderns Data Center (DC) are equipped to handle high data rate to meet consumer high bandwidth demand. FEC Analysis is one of the important measurements in DC now a days.
T&M
Optical Fiber
400G Ethernet FEC Analysis Ethernet equipment interfaces use optical modules. With some exceptions, pass/fail verification of optical modules up to 100G is performed simply by measuring the bit error rate (BER) for a fixed period of repeated sending and receiving of signals to confirm the error-free status. Similarly, network throughput and latency are measured using a BERT. However, the 400G Ethernet PMD layer is switching to PAM4 and FEC (Forward Error Correction) to correct errors occurring at optical transceivers and networks transmitting extremely fast signals, and to assure both communications quality and lower costs. FEC is a technology for correcting errors within the correctable range, and assures high reliability as well as extended transmission distance.
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Optical Fiber
BER Test: BER test consist of many tests such as Generation and detection of test patterns, Count of errors in received test pattern, Pattern generation: Unframed (Layer 1), Framed Ethernet (MAC) header (Layer 2), Framed Ethernet (MAC) header with IP header (Layer 3) or Framed Ethernet (MAC) header, Framed with IP header and TCP/UDP header (Layer 4), User-defined header pattern (14 byte to 256 byte), Detection of sequence errors, loss of sequence synchronization, Frame loss count and frame loss seconds.
FEC Analysis:
WDM Circuit Metro DC
arrive at their destinations successfully & is measured in bits per second. Packet loss, latency, and jitter are all related to slow throughput speed.
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