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13/06/2014 OTF-6top. IPv6 over the TSCH mode of IEEE 802.15.4e. Chairs: Pascal Thubert Thomas Watteyne Etherpad for minutes: http://etherpad.tools.ietf.org:9000/p/6tisch. 1. 1. 1. 6top & OTF discussion & last updates in the OTF draft. Maria Rita Palattella. OTF and tracks.
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13/06/2014 OTF-6top IPv6 over the TSCH mode of IEEE 802.15.4e Chairs: Pascal Thubert Thomas Watteyne Etherpad for minutes: http://etherpad.tools.ietf.org:9000/p/6tisch 1 1 1
6top & OTFdiscussion & last updates in the OTF draft Maria Rita Palattella
OTF and tracks • OTF can ask for more BW to 6top, by using the CREATE.softcell command. • A softcell belong to a bundle, a bundle is associated to a track, and thus, the softcell is associated to a track too. • Q1: should OTF use a single track (best effort) or multiple tracks? • R1 [MR]: Multiple tracks more realistic, but make OTF- design more complex • Q2: when OTF asks for more BW, does it have to specify the track the softcell belongs to? • R2 [Qin]: two options for the relationship between softcell and Track (1) softcellbelongs to unique Track if TrackID has specific value (2) softcellbelongs to all of tracks on sender if the TrackID is empty a) In which case this option 2) should be used by OTF? b) How and when that softcell will be allocated on a specific track?
OTF and 6top commands • READ.cellcan be used for getting information, about a set of metrics (e.g., link quality: LQI, EXT, PDR) for a specific cell. By checking on the quality and usage of that cell, it is possible to decide if it is better to still reserve it or delete it. • Q1: can OTF use such command, if it doesn’t have access to detailed cell’s information (i.e., slotoffset, channeloffset)? • R1 [Qin] it can, by using the CoAP+YANG Model as the management interface between OTF and 6top? • Q1a: in which way? • CellList provides per cell per track statistics • Q2: can OTF use such command? • R2 [Qin]: it can, by using the CoAP+YANG Model (i.e., filter option of CoAP) • From 6top point of view, both OTF and PCE are same in terms of access MIB. How OTF (and in general, a module above 6top) can access 6top MIB more efficiently? By using CoAP + YANG module?
6top Monitoring FunctionReallocation • The function of Monitoring in 6top is responsible for re-allocating soft cell, i.e., associate a exiting cellID to another (slotOffset, channelOffset) while the link quality of the original (slotOffset, channelOffset) is lower than a given threshold. Like OF in RPL, 6top does not define how to make decision on re-allocation and leave it to other drafts and future. • OTF does not deal with re-allocation!!! • Q1: But how such re-allocation function can impact OTF operation? • R1[Qin]: it can provide better cells for given BW requirement from OTF. • Q2: Should OTF somehow be inform by OTF when some cells are reallocating? If yes, in which way?
6top Monitoring FunctionOverprovision 6top is able to operate overprovision. In fact, The monitoring function can be used to guarantee the BW required by upper layer, e.g., OTF. OTF works on different layer from the monitoring function of 6top. Thus, they should not conflict with each other. Example: Assume upper layer requires some add bandwidth, saying 2 slots in a specific slotframe; the average Packet Delivery Rate is 75%; then, 6top will reserve 3 slots in the slotframe to meet the bandwidth requirement. In addition, when the link quality drop to 50%, 6top will reserve total 4 slots to meet the bandwidth requirement.
6top Actuation <The cell quality statistics MAY be used to generate soft a cell Maintenance command, which triggers a soft cell Maintenance procedure. The traffic load statistics MAY be used to generate internal Create (resp. Delete) soft cell commands, which triggers a soft cell Reservation (resp. Remove) process. The policy to generate the soft cell Maintenance command and the policy to generate Create/Delete soft cell commands is out of 6top scope.> • Q1: Can OTF provide a policy for generating CREATE/DELETE soft cell commands? • R1 [Qin]: Yes, OTF can provide one of the possible policies for computing BW and generating CREATE/DELETE cells. Other policies may be defined in the future. That why it will be implementation-specific (each implementation will decide which policy to use)
6top & OTFlast updates in the OTF draftnext steps Maria Rita Palattella
OTF Last Updates • Last version edited by Maria Rita in April 2014 • Added explanations about 6top commands (CREATE/DELETE cell) used by OTF for requesting more/less BW • [still TODO] Better explain how the same commands are used for creating/deleting, increasing/decreasing size of bundle (as per Thomas’ request)
Re-organization of the TOC Current TOC New TOC Introduction Allocation policies Allocation methods OTF Bandwidth management(i.e., events triggering OTF) Schedule storage on OTF 6top-OTF Interface (CoAP-YANG Model?) Cell/Bundle Reservation/Deletion Getting cells’ statistic from 6top Bandwidth Estimation Algorithm Acknowledgements References
Next steps • Update TOC (if agreed) • [MR] Add content about OTF-6top interaction (need first to clarify with Qin) • [Nicola] Add content about reactive/proactive approach, instead of post/pre and hybrid-allocation; use of threshold. Update section on Allocation policies and section on BW Estimation Algorithms • [Alfredo] Add content about OTF events • [Diego] Add content about 6top-OTF interface (CoAP-YANG model?) • FINAL DEADLINE (cut-off date): 4/7/2014