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Minutes, 02 September 2016 interim, 6TiSCH WG
Note: timestamps in PDT.
Connection details
- Date: 7-8am Pacific: http://www.worldtimebuddy.com/?qm=1&lid=100,12,5392171,1850147&h=100&date=2016-09-02&sln=14-15
- Webex link: https://cisco.webex.com/ciscosales/j.php?MTID=md64a0958ae4154c0553f056bf42b756a
- Webex recording: https://cisco.webex.com/cisco/ldr.php?RCID=226b78276ffb28d51924c5bb66be848e
- password: YpZJNJ4D
- Wiki: https://bitbucket.org/6tisch/meetings/wiki/160902_webex
- Slides: https://bitbucket.org/6tisch/meetings/src/master/160909_webex/slides_160902_webex.ppt join slides: https://docs.google.com/presentation/d/1Z3YpcRxG1RvntMZHpIcLifaKRBsmh94RPg48RPgmSLY/edit?usp=sharing and: https://bitbucket.org/6tisch/meetings/src/dc172467a453aeec51ef530aa48f12f5d74cc9c3/160902_webex/6tisch-join-bandwidth.pdf?at=master&fileviewer=file-view-default
Taking notes (using Etherpad)
- Xavier Vilajosana
- Pascal Thubert
Present (alphabetically by first name)
- Diego Dujovne
- Francesca Palombini
- Georgios Papadopoulos
- Malisa Vucinic
- Michael Richardson
- Nicola Accettura
- Pascal Thubert
- Qin Wang
- Rashid Sangi
- S.V.R. Anand
- Tengfei Chang
- Thomas Watteyne
- Xavier Vilajosana
Action Items
- Thomas to propose to the ML the mechanism in order to allocate TX/RX cells instead of only TX as it is now
Agenda
- Administrivia [2min]
- Approval agenda
- Approval minutes last call
- IETF update [Chairs] [5min]
- update 6top [Thomas] [20min]
- update security [Michael, chairs] [10min]
- introduce new DT / New angle
- Potential for both minimal/PSK (based on Art)
- and a more ANIMA-like solutions (DT task)
- Next steps for SF0 [Pascal] [20min]
- Target: Experimental?
- Cell allocation Scheme
- AOB [1min]
Minutes
- 7:05 Meeting starts
- recording started
- first meeting after IETF 96 in berlin
-
Administrivia [2min]
- Approval agenda
No issues raised. Agenda approved.
- Approval minutes last call
No issues raised. Minutes last call approved.
- Approval agenda
-
IETF update
- minimal draft for many days in the IESG review queue
- There are still reviewers that have not looked to the latest version
- we expect reviews by 2 weeks from now.
- milestones for 6tisch have been reviewed
- 6top sublayer -> 6P
- we need to agree the date to do the updates according to the progress of the draft
-
Update on 6top (Xavi)
- changes in 6top since ietf meeting
- Multiple changes made before summer break presented by Xavi at IETF
- Thomas introduces further proposals. We believe that after this proposals the draft will be ready.
- STATUS command
- 6P status command replaces the COUNT cmd
- Response contains 2 counters (cells from A to B and B to A -- A is the node that requests)
- 6Top LIST it has a pagination problem. It did not work if we listed more than the cells that fit in a page.
- in the new version of the command we can ask for a number of cells starting from an offset.
- the answer is a list of cells.
- Xavi points that Tero proposed an additional improvement; if we ask for too many cells they may not fit because of IEs that may need to be placed. So the number of cells should be a max number not the total number, best effort for the responder to put as many as it can.
- Thomas asks clarification; Xavi adds that the size of headers depends on the IEs, so no guarantee that we can always place all the cells
- Thomas indicates that the draft already has a meaning for RC 1, no more cells available; maybe need a new RC.
- Thomas: Complicated one: consistency probme found at plugtest. If one node is not aware that it has a cell availabel, it will never be used and the error will not be detected. Solution is to have a generation number to figure the latest change. Since there is no concurrent transaction between 2 peers, a counter can detect mismatch. 2 bits is for lollipop behavior to detect a reset. At every packet neighbors check consistency, action on inconsistency s to be taken by the SF (clear is recomended)
- Generation numbers are used to check the consistency between the schedule of two nodes.
- the counter has 2 bits. this is enough as there are no concurrent transactions
- the lollipop counter starts by 0 upon clear or start, then it goes from 1 to 2 or 2 to 1 but never reaches 0 unless there is a clear.
-
Update on security
- when we issue a clear cmd, both nodes clear their schedules.
-
Proposals by Thomas:
- enable the allocation of cells from the receiver side. This enables a parent to defragment or build a better schedule.
- propose a TX/RX flag in the cell add command
- Action: Thomas to propose to the ML the mechanism in order to allocate TX/RX cells instead of only TX as it is now.
- Pascal: It is possible to indicate the latency in a child node so a parent may decide to reshuffle. We need a "Move" command
- On a failed 6P ADD the response may add a suggestion for the cells to allocate.
- Nicola: another option could be that the transmitter proposes all the available cells in the transmitting side.
- the representation of the cells is ope to the SF so the format can be defined by the SF. The 6P only proposes a format but can be overriden.
- enable the allocation of cells from the receiver side. This enables a parent to defragment or build a better schedule.
-
update on security (Michael Richardson)
- Need a simple PSK solution
- we are now considering a variation
- Maria-Rita:
- shows a diagram with different nodes in a network, Some nodes aim to join. One node is malicious. One is misplaced in the network.
- One slide shows the flows of information from the joining nodes to the JCE
- JCE can decide to spread the join load in the network, sequentially, etc..
- Thomas: how the JCE nows that there are pending initiations?
- Maria-Rita: pledge initiated connection. We allow join traffic, we have a specific period where we accept join traffic
- Maria-Rita: we want to avoid to waste bw and energy.
- Idea: give each pledge an interval between retries. They use the best effort space for join traffic.
-
Nextext steps for SF0
- No time for this item today. We'll schedule it for the next call on September 23.
-
AOB [1min]
- No issues raised.
Updated