![]() It is a high-speed local area network standard that can operate at data rates up to 1 Gbit/s over existing home wiring ( power lines, phone lines and coaxial cables). ITU-T G.hn uses hybrid ARQ, a mixture of high-rate forward error correction (FEC) and ARQ. IEEE 802.11 wireless networking uses ARQ retransmissions at the data-link layer. The Transmission Control Protocol uses a variant of Go-Back-N ARQ to ensure reliable transmission of data over the Internet Protocol, which does not provide guaranteed delivery of packets with Selective Acknowledgement (SACK), it uses Selective Repeat ARQ. These protocols reside in the data link or transport layers (layers 2 and 4) of the OSI model. All three protocols usually use some form of sliding window protocol to help the sender determine which (if any) packets need to be retransmitted. Variations of ARQ protocols include Stop-and-wait ARQ, Go-Back-N ARQ, and Selective Repeat ARQ. If the sender does not receive an acknowledgment before the timeout, it re-transmits the message until it receives an acknowledgment or exceeds a predefined number of retransmissions. ARQ is appropriate if the communication channel has varying or unknown capacity. ( June 2018) ( Learn how and when to remove this template message)Īutomatic repeat request ( ARQ), also known as automatic repeat query, is an error-control method for data transmission that uses acknowledgements (messages sent by the receiver indicating that it has correctly received a message) and timeouts (specified periods of time allowed to elapse before an acknowledgment is to be received) to achieve reliable data transmission over an unreliable communication channel. Please help to improve this article by introducing more precise citations. I have been using Crashplan as my backup tool since February 2015.This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. At the time, I bought into their four year family plan (=multiple computers) for 429.99 USD. But Crashplan turned out to be a memory hog (especially if you have a multi-terrabyte harddrive) and it was clear that I want a better solution so I started looking for an alternative in 2016, one year before the subscription was supposed to end. I focused on software solutions that would allow me to back up to whichever storage I want so that I would be in better control of my data (Crashplan at some point deleted an entire backup of mine because the computer it was associated with hadn’t backed up anything for more than six months. Apparently it was in line with their Terms of Service, but deleting backups is not a goof thing to do for a backup company). I spend a lot of time testing various solutions, including Arq, Goodsync, Cloudberry, SyncBackPro and Syncovery. Goodsync, Cloudberry and SyncBackPro were out pretty quickly :Ĭloudberry cannot handle backups larger than 1TB unless you buy the enterprise version for 300 USD. Goodsync had crap customer service (reasonably fast response, but useless and not answering my question) and it was designed more for syncing than for backing up (although backing up is possible). ![]() (Well actually you can change the source folder and the original stuff in the backup will remain but will no longer be backed up.) With SyncbackPro, the restore process seemed rather complicated and once a folder is selected as the source, you cannot add other folders to that backup job. Syncovery was very promising but I kept bumping into bugs and errors and I spend a hell of a lot of time helping the developer debug these problems and he actually ended up compensating me for some of that work. So while my experience with the software was not so good in the end, I can only say good things about the support by the developer. He listened patiently to my problems and although he insisted that he has lots and lots of customers where the software works fine, I did manage to convince him to look at the issues I had (this is how it should be but not all developers/companies do that) and we managed to track down a couple of bugs but it seemed a neverending story and so I eventually decided to scrap syncovery and start looking anew, even though this entailed that I would probably have to pro-long my Crashplan subscription another year. This is when I discovered duplicati 2 and although it was still in beta, it looked very promising. In particular, I liked that it is open source and future proof in the sense that I would always be able to access my encrypted data, even in decades when duplicati may no longer be maintained.
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