Synchronous v Asynchronous

[motoxmacman]

hi
bit of a simple one perhaps for you guys, but it doesn't seem to stick for me. i have read the Acadamy definition, looked on wikipedia and todd lammle definition in the ccna book and it seems to contradict itself.

Does any body have an easy definition or easy way to remember in which case either is used?

any help appreciated.
chris

 

[CiscoRC]

I wouldn't use Wikipedia for any Cisco product definition. To get full detailing info on the 2..

Asynchronous replication does not depend on acknowledging the remote write, but it does write to a local log file.

Synchronous replication depends on receiving an ACK from the remote system and the remote system also keeps a log file.

Async is fastest. It is impossible to accurately recreate data at the remote end because there is no way of knowing what was successfully transmitted. However, if there is a disaster at the local site, data will need to be rebuilt from the log file. If the local log file is gone, then traditional backup/recovery is needed.

If synchronous replication is used the remote site data could be used to rebuild data at the local site. In that sense, synchronous replication is more secure by providing additional redundancy.

Hope this definition helps give you an idea on the comparison.

Peace



***************
R. Corrigan Jr.
Network+, (working on CCNA)

 

[CiscoGuy33]

motoxmacman,

I agree with CiscoRC on Wikipedia - never know exactly what you will get even when it looks like it was done by a pro

I have this book on my desk by Cisco Press Dictionary of Internetworking Terms and Acronyms (Paperback) About $.01 + $4 for shipping used, book is older but most of the terms have not changed and for $4.01 you can not go wrong

http://www.amazon.com/Dictionary-Internetworking-Terms-Acronyms-Systems/dp/1587200457

I also have the Sybex book Dictionary of Networking (Paperback) by Peter Dyson. About $.50 used + $4 shipping, this book includes a CD.

http://www.amazon.com/Dictionary-Networking-Peter-Dyson/dp/0782124615

Both these books are older but for less then $10 you can have a pretty good reference for when you have questions as you study.

Hope this helps!


E.A. Broda
CCNA, CCDA, CCAI, Network +