Hello Xavi:
Not sure what you want me to add?
At the moment the text reads:
“
4.2.2. Scheduling Functions and the 6P protocol
In the case of soft cells, the cell management entity that controls
the dynamic attribution of cells to adapt to the dynamics of variable
rate flows is called a Scheduling Function (SF). There may be
multiple SFs with more or less aggressive reaction to the dynamics of
the network. The 6TiSCH 6top Scheduling Function Zero (SF0)
[I-D.ietf-6tisch-6top-sf0] provides a simple scheduling function that
can be used by default by devices that support dynamic scheduling of
soft cells.
The SF may be seen as divided between an upper bandwidth adaptation
logic that is not aware of the particular technology that is used to
obtain and release bandwidth, and an underlying service sublayer that
maps those needs in the actual technology, which means mapping the
bandwidth onto cells in the case of TSCH.
+------------------------+ +------------------------+
| Scheduling Function | | Scheduling Function |
| Bandwidth adaptation | | Bandwidth adaptation |
+------------------------+ +------------------------+
| Scheduling Function | | Scheduling Function |
| TSCH mapping to cells | | TSCH mapping to cells |
+------------------------+ +------------------------+
| 6top cells negotiation | <- 6P -> | 6top cells negotiation |
+------------------------+ +------------------------+
Figure 6: SF/6P stack in 6top
The SF relies on 6top services that implement the 6top Protocol (6P)
[I-D.ietf-6tisch-6top-protocol] to negotiate the precise cells that
will be allocated or freed based on the schedules of the peer. It
may be for instance that a peer wants to use a particular time slot
that is free in its schedule, but that timeslot is already in use by
the other peer for a communication with a third party on a different
cell. The 6P protocol enables the peers to find an agreement in a
transactional manner that ensures the final consistency of the nodes
state.
“
In fact, I realize I’m not 100% clear what whether people think that SF belongs
to 6top or sits over it as a service user.
Part of the confusion is the name of the SF0 draft “6TiSCH 6top Scheduling
Function Zero (SF0)” which tends to indicate that it is part of it.
Take care,
Pascal
From: [email protected] [mailto:[email protected]] On Behalf Of Xavier
Vilajosana
Sent: samedi 4 juin 2016 06:26
To: Thomas Watteyne <[email protected]>
Cc: Pascal Thubert (pthubert) <[email protected]>; [email protected]
Subject: Re: [6tisch] proposed text to describe SF and 6P in archie
Hi Pascal, Thomas, all
inline too (see changes in *foo*)
regards,
X
2016-06-03 20:41 GMT+02:00 Thomas Watteyne
<[email protected]<mailto:[email protected]>>:
Pascal,
Some typos and suggestions below.
4.2.2. Scheduling Functions and the 6P Protocol (6P)
In the case of soft cells, the cell management entity that controls
the dynamic attribution of cells to adapt to *varying*
rate flows *in the network* is called Scheduling Function (SF). There may be
multiple SFs, each implementing a different policy to adapt to varying
network traffic. The 6TiSCH 6top Scheduling Function Zero (SF0)
[I-D.ietf-6tisch-6top-sf0] provides a simple scheduling function that
can be used by default by devices that support dynamic scheduling of
soft cells.
The SF is logically divided in a bandwidth adaptation policy
which is *independent* to the particular *mechanism* used to obtain and
release bandwidth,
TW> I don't understand the previous sentence
and a underlying service sublayer which identifies
XV> Only identifies? For me we need to stress the difference between 6top
protocol and this sublayer
the
appropriate TSCH cells to use.
+------------------------+ +------------------------+
| Scheduling Function | | Scheduling Function |
| Bandwidth adaptation | | Bandwidth adaptation |
+------------------------+ +------------------------+
| Scheduling Function | | Scheduling Function |
| TSCH cell mapping | | TSCH cell mapping |
+------------------------+ +------------------------+
| 6top cells negotiation | <- 6P -> | 6top cells negotiation |
+------------------------+ +------------------------+
Figure 6: SF/6P stack in 6top
The SF relies on the 6top Protocol (6P)
[I-D.ietf-6tisch-6top-protocol] to negotiate the cells between
neighbor nodes. It
may be for instance that a node wants to use a particular time slot
that is free in its schedule, but which is already in use by
its neighbor. The 6P protocol enables the neighbor nodes to find
an agreement on which cells to use.
On Friday, June 3, 2016, Pascal Thubert (pthubert)
<[email protected]<mailto:[email protected]>> wrote:
Dear all:
As discussed at the last Interim, please find proposed text in the 6TiSCH
architecture below.
What do you think?
Pascal
4.2.2. Scheduling Functions and the 6P protocol
In the case of soft cells, the cell management entity that controls
the dynamic attribution of cells to adapt to the dynamics of variable
rate flows is called a Scheduling Function (SF). There may be
multiple SFs with more or less aggressive reaction to the dynamics of
the network. The 6TiSCH 6top Scheduling Function Zero (SF0)
[I-D.ietf-6tisch-6top-sf0] provides a simple scheduling function that
can be used by default by devices that support dynamic scheduling of
soft cells.
The SF is logically divided in an abstract bandwidth adaptation logic
that is abstract to the particular technology used to obtain and
release bandwidth, and a underlying service sublayer that maps those
needs in the actual technology, which means identifying the
appropriate cells in the context of TSCH.
+------------------------+ +------------------------+
| Scheduling Function | | Scheduling Function |
| Bandwidth adaptation | | Bandwidth adaptation |
+------------------------+ +------------------------+
| Scheduling Function | | Scheduling Function |
| TSCH mapping to cells | | TSCH mapping to cells |
+------------------------+ +------------------------+
| 6top cells negotiation | <- 6P -> | 6top cells negotiation |
+------------------------+ +------------------------+
Figure 6: SF/6P stack in 6top
The SF relies on 6top services that implement the 6top Protocol (6P)
[I-D.ietf-6tisch-6top-protocol] to negotiate the precise cells that
will be allocated or freed based on the schedules of the peer. It
may be for instance that a peer wants to use a particular time slot
that is free in its schedule, but that timeslot is already in use by
the other peer for a communication with a third party on a different
cell. The 6P protocol enables the peers to find an agreement in a
transactional manner that ensures the final consistency of the nodes
state.
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--
_______________________________________
Thomas Watteyne, PhD
Research Scientist & Innovator, Inria
Sr Networking Design Eng, Linear Tech
Founder & co-lead, UC Berkeley OpenWSN
Co-chair, IETF 6TiSCH
www.thomaswatteyne.com<http://www.thomaswatteyne.com>
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