Editing Rain fade (section)

== Parallel fail-over links ==

In terrestrial point to point microwave systems ranging from 11&nbsp;GHz to 80&nbsp;GHz, a parallel backup link can be installed alongside a rain fade prone higher bandwidth connection.<ref>{{Cite web |title=Diversity in Microwave Links |url=https://www.cablefree.net/wirelesstechnology/microwave/diversity-in-microwave-links/ |access-date=2023-10-27 |website=CableFree |language=en-GB}}</ref> In this arrangement, a primary link such as an 80&nbsp;GHz 1&nbsp;Gbit/s full duplex microwave bridge may be calculated to have a 99.9% availability rate over the period of one year.<ref name=":0">{{Cite web |date=2015-04-13 |title=Microwave Link |url=https://www.microwave-link.com/ |access-date=2023-10-27 |website=Microwave Link |language=en-GB}}</ref> The calculated 99.9% availability rate means that the link may be down for a cumulative total of ten or more hours per year as the peaks of rain storms pass over the area.<ref name=":0" /> A secondary lower bandwidth link such as a 5.8&nbsp;GHz based 100&nbsp;Mbit/s bridge may be installed parallel to the primary link, with routers on both ends controlling automatic failover to the 100&nbsp;Mbit/s bridge when the primary 1&nbsp;Gbit/s link is down due to rain fade. Using this arrangement, high frequency point to point links (23&nbsp;GHz+) may be installed to service locations many kilometers farther than could be served with a single link requiring 99.99% uptime over the course of one year.<ref>{{Cite web |date=2017-11-28 |title=Point to Point Archives - Page 2 of 3 |url=https://www.microwave-link.com/tag/point-to-point/ |access-date=2023-10-27 |website=Microwave Link |language=en-GB}}</ref>