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Re: manager subscription model for notifications: usage survey
On Mon, May 01, 2006 at 08:23:33PM +0300, Romascanu, Dan (Dan) wrote:
> Is it really much more complex to implement than the SNMP-TARGET-MIB and
> SNMP-NOTIFICATION-MIB?
You are right that the SNMP-TARGET-MIB and SNMP-NOTIFICATION-MIB
basically allow subscriptions (and they are pretty complicated to use
with all the features that went in). These MIBs, however, have two
problems that are important if you want to use them:
a) Notification targets can't be bound to a "session" nor are there any
timers which cause targets to expire if the timer is not refreshed.
Hence, garbage collection of dead dynamic subscriptions is a mess.
This is an engineering problem which could be fixed easily by
adding the missing capability to the standards.
b) Most default installations are simply read-only and it typically
requires to use the CLI to add a subscription. Given the lack of
standards in this space, you can't really write interoperable code
that actually works in operational networks. This is mainly a
deployment problem and could be solved by agreeing on common access
control setups that actually allow more useful work to happen (but
again will take a long time to become effective).
By introducing a subscription mechanism which uses additional protocol
verbs rather than a writable data model, you kind of automatically
make it much more likely that neither a) nor b) becomes a problem.
Subscription operations make management applications that like to
subscribe to notifications easier to write and I believe this is a
feature and not a bug.
/js
--
Juergen Schoenwaelder International University Bremen
<http://www.eecs.iu-bremen.de/> P.O. Box 750 561, 28725 Bremen, Germany
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