V Guruprasad wrote:
On Fri 2002.11.01, Keith Moore wrote:
so when the address changes out from under the app, or there are
multiple hosts bound to a single domain name, the app loses.
I don't see why name-address caching within the kernel cannot be as
good or as bad as caching in the user space. I believe this would be
an important area that the current Linux implementation of INFS allows.
The problem is that only the app knows what kind of caching behavior it
needs. For a simple protocol like SMTP or HTTP, pure DNS-based caching
is fine; for a more sophisticated protocol (e.g., any sort of
videoconferencing app), it may be necessary to ensure that each
connection associated with a given session go to the same address.
Very briefly, the two main reasons are (a)
that any fixed-length numeric address space automatically sets a
hard limit and resists expansion, as we are finding from the IPv6
migration,
The fixed-length numeric addresses still need to exist, and their nature
still needs to be coded into all hosts and routers. Hiding them from
the apps will not make it easier to upgrade the installed base.
and (b) not depending on fixed-length numeric addresses
as primary (user & application level) addresses would enable the
network to auto-aggregate its addresses and routes.
You're talking about permitting automatic renumbering. How does that
happen without disrupting established TCP connections?
--
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|John Stracke |jstracke(_at_)centivinc(_dot_)com |
|Principal Engineer|http://www.centivinc.com |
|Centiv |My opinions are my own. |
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|If you're going to walk on thin ice, you might as well *dance*!|
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