Map Development Area (MDA)
Location:
_/_
internet
_/_
dns
_/_
dns-caching
| dns-caching |
|
|
|
-
Comment:
-
but works only if the number of changes is small compared to the number of read requests
-
result
-
dramatic speed up of overall operation
-
Comment:
-
controls how long a server will cache a piece of information
-
Comment:
-
read-often/write-seldom semantics
-
result
-
most common requests handled fastest
-
example
-
after a request for something.com to a server, it memorizes the IP address for the name server handling something.com
-
Comment:
-
when a name server resolves a request, it caches all the information
-
Comment:
-
every dns record has TTL (time to live) counter (unit: seconds)
|
|
|
