Subject: Re: [6tsch] summary NSIS

From: "Bless, Roland (TM)" <[email-masked]>
Date: Fri, 03 May 2013 13:27:53 +0200

Hi Xavier,

Am 12.04.2013 17:11, schrieb Xavier Vilajosana:
> you said that NSIS will be suitable to support PCE management networks.
> Can you explain how NSIS will work in the following scenario:
> 
> " A PCE computes the schedule for a set of devices in a TSCH network,
> which includes information such as a collection of tuples
> <time_slot,ch_offset,destination_address,link_type> for each node in the
> set. The PCE needs to install that information in the schedule of each
> node meaning that each node has to receive that information."
> 
> From your emails I have the intuition that:
> 1) QSPEC messages can be extended to carry that information.

Yes.

> 2) NSIS QoS on GIST can be used to send the message along the route so
> each of the nodes in the set receive the configuration
> 
> However I don't see very clear how GIST will build the "path" to each of
> this nodes. Will it use a reverse-reservation (initiated from the
> receiver?)

> Can you illustrate that scenario please?

Honestly, I don't know the exact scenario that _you_ have in mind
and I'm not very well versed yet in the PCE or TSCH architectures,
but IMHO you can use various means. Again, GIST assumes that you
have a working forwarding path already installed by different means.

>From your quotation I can imagine to use a group address for all nodes
and use a "sender-initiated" reservation. We added multicast support to
GIST which isn't such a big deal [1]. However, this message needs to
contain all schedules of all devices then.
If you want to do it individually, you can simply send it from the PCE
to each device. You can use a "sender-initiated" RESERVE for this
employing the EST MRM
http://tools.ietf.org/html/draft-bless-nsis-est-mrm-02
if the sender and receiver of the respective flows are not
PCE or PCC.

[1] http://nsis-ka.org/wiki/IpMulticastSupportForNSIS

Regards,
 Roland