H3C S5820X SERIES High Availability Configuration Manual

Also see for s5800 series: Installation manual Instruction manual Command reference Quick start Troubleshooting guide

Contents

H3C S5820X SERIES High Availability Configuration Manual Manual pdf 13 page image

1High availability overviewCommunication interruptions can seriously affect widely-deployed value-added services such as IPTVand video conference. Therefore, the basic network infrastructures must be able to provide highavailability.The following are the effective ways to improve availability:• Increasing fault tolerance• Speeding up fault recovery• Reducing impact of faults on servicesAvailability requirementsAvailability requirements fall into three levels based on purpose and implementation, as shown in Table1.Table 1 Availability requirementsLevel Requirement Solution1 Decrease system software andhardware faults• Hardware: Simplified circuit design, enhancedproduction techniques, and reliability tests.• Software: Reliability design and test2 Protect system functions from beingaffected by failures Device and link redundancy and switchover3 Enable the system to recover as fastas possibleFault detection, diagnosis, isolation, and recoverytechnologiesThe level 1 availability requirement should be considered during the design and production process ofnetwork devices. The level 2 availability requirement should be considered during network design. Thelevel 3 availability requirement should be considered during network deployment, according to thenetwork infrastructure and service characteristics.Availability evaluationMean Time Between Failures (MTBF) and Mean Time to Repair (MTTR) evaluate the availability of anetwork.MTBFMTBF is the predicted elapsed time between inherent failures of a system during operation. It is typicallyexpressed in hours. A higher MTBF means a higher availability.MTTRMTTR is the average time required to repair a failed system. MTTR in a broad sense also involves spareparts management and customer services.