[Netconf] Updated draft-mm-netconf-time-capability-01

[Tal Mizrahi <[e-mail]>]

Hi,

We have posted an updated draft:
http://tools.ietf.org/html/draft-mm-netconf-time-capability-01

Thanks to all the people who reviewed and sent comments about draft 00.
Here is a summary of the changes compared to draft 00:
-	We have added discussion about the scheduling tolerance: an upper  
bound on how far into the future/past an RPC can be scheduled.
-	The scheduled time now refers to the *start* time of the operation,  
rather than to its completion.
-	The time format has been changed to date-and-time.

There is a key issue that we would like to raise. There is a  
well-known distinction between *hard* real-time and *soft* real-time  
scheduling; hard-real time implies that if one of the servers does not  
perform the scheduled operations on time the system may fail, whereas  
soft real-time means that the system will perform better if all the  
servers invoke the operations on time, but nothing breaks even if they  
don’t.

We received quite a bit of comments and questions, that we believe are  
more relevant to the *hard* real-time case, for example: what happens  
if a server is unable to schedule the RPC to the scheduled time? is  
there a way to remove pending scheduled operations? What if the NACM  
rules change while the operation is pending? What if the server  
reboots while operations are pending?

We believe the current draft allows soft real-time scheduling, i.e.,  
it provides the tools to schedule an RPC without strict guarantees. An  
implicit assumption here is that RPCs are scheduled to near-future  
deadlines (e.g., on the order of seconds in the future), which allows  
a long enough time for the NETCONF message to be delivered to the  
server, but not enough time for (or a very low probability of)  
significant changes in the server, such as NACM rule changes, or  
server restart.

At this point, draft 01 is soft-real-time-oriented. We are interested  
to hear feedback about whether there is an interest in the working  
group to develop the hard real-time functionality as well.

Regards,
Tal Mizrahi.