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Principal Sponsors:
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Five-Nines at the IP Edge |
Overview
Reliability is a key variable in evaluating network performance. Reliability is measured in "nines" in the world of network technology. Simply stated, reliability is represented by the number of times the number "9" appears in the reliability rating and is measured as a percentage of uptime, and described by the amount of time a network is available (or unavailable). For example:
So, if a network is unavailable for a period of five minutes per year, or less, we can say it is 99.999% reliable. Another way of saying this is that the network has "five-nines" reliability.
Five-nines availability is a staple in traditional networks. Now that Internet protocol (IP)–based communications are mission critical, customers are demanding the same level of availability from their service providers' IP networks. Although IP networks run on top of a resilient optical transmission layer and the IP core can yield high availability with a diversely routed mesh of routers, the IP edge remains a single point of failure. This tutorial looks at the requirements for availability in IP networks, dissects the anatomy of service recovery, and examines the five-nines IP network's economic and competitive advantages.
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