[Nsi-wg] time issue

[Tomohiro Kudoh]

Hi all

I would like to point out several things.

1. Automatic cannot be used for on-demand (or immediate) reservation
for tree. When you want to provision an inter-domain connection
through multiple networks (domains), some networks will provision
requested intra-domain connections even if some networks denies the
request. So, for on-demand, the requester must confirm all
participating NSAs agree to provide intra-network connections first,
and then let all NSAs to provision. So, explicit (manual) provisioning
must be used for on-demand. For automatic, the start time should be
sufficiently in future. (2PC solves this problem, but we decided to
not to use 2PC for ver. 1)

2. Service start time from user's point of view is very difficult to
define. For example, for Ethernet connection, there may be L2 switches
in networks and/or at the edge. ARP exchange may take some time, and
if STP (Spanning Tree Protocol, here) is working, it will take longer
time before user can actually exchange packets.

3. For some applications, application might not want a connection in
service before/after certain time for security reasons.

Tomohiro