Splicing in a Mesh Network Month Year doc.: IEEE 802.11-yy/xxxxr0 May 2005 Splicing in a Mesh Network Date: 2005-05-11 Authors: Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http:// ieee802.org/guides/bylaws/sb-bylaws.pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair <stuart.kerry@philips.com> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee.org>. Mathilde Benveniste, Avaya Labs John Doe, Some Company

‘Splicing’ in a mesh network May 2005 ‘Splicing’ in a mesh network Mathilde Benveniste Benveniste@ieee.org Mathilde Benveniste, Avaya Labs

May 2005 Introduction The CCC protocol that enables reservation of mesh traffic (MT) channels to be made on a single control channel monitored by all MPs is presented starting in Doc IEEE802.11-5-0422r0 We have discussed how interference from users of the same RF spectrum band in various BSSs associated with the mesh can be prevented We are concerned here with interference caused by independent 802.11 systems operating on the same RF spectrum Two types of interferers are considered: Those operating on channels used for mesh traffic Those operating on the mesh control channel Mesh traffic channels serving independent co-channel users are avoided by limiting channel selection within a set of permissible channels for each mesh point We show how the control channel can be changed or “spliced” to operate on two different physical channels in order to avoid interference from mesh-independent stations Mathilde Benveniste, Avaya Labs

Permissible Set of MT channels May 2005 Permissible Set of MT channels APs that are independent of a mesh may operate in the neighborhood of mesh points on the same channel. As a consequence the channel should be avoided as either a control channel or a mesh traffic channel A "permissible“ set of channels is maintained by an MP; the MP select its MT channels from the permissible set The permissible set contains channels that are not heavily loaded with non-mesh traffic or traffic from a non-mesh-associated BSS Channels are monitored regularly in order to avoid such channels from being included in the permissible set, which is updated over time  If an independent AP powers on and chooses to operate on one of the permissible channels, that channel is removed from the permissible set.   Mathilde Benveniste, Avaya Labs

May 2005 MT Channel NAV A NAV is maintained by a MP on all channels on the permissible set The NAV of a channel is updated by NAV setting requests for the channel reserved transmitted on the control channel, and NAV setting requests transmitted on each traffic channel by any stations/APs that may be operating on that channel and are received by a MT radio while tuned to that channel  If the MP has a fixed MT channel assigned to it, it will be synchronized always with all NAV setting requests on the MT channel   If the MP switches MT channels, Collisions are possible if the MRTS asks for such a channel before the latter is removed from the permissible set The MP performs carrier sensing before transmitting and will back off to avoid such collisions  NAV synchronization can be achieved with greater probability by tuning to the MT channel before the MP is ready to transmit Tuning should occur no latter than the generation and queueing of a MRTS or MCTS Mathilde Benveniste, Avaya Labs

Control Channel Change May 2005 Control Channel Change Independent APs operating in the mesh area, on the same channel as the mesh control channel, may force a nearby MP to request a change of the control channel Such a change is accommodated either by forwarding the control channel change request to all MPs, or by “splicing” the channel We show how these requests are performed Mathilde Benveniste, Avaya Labs

Splicing: changing control channel May 2005 Splicing: changing control channel Splice Authorizing MP Control channel 1 independent AP, L, operates in the mesh area on the same channel as the mesh control channel; MP G requests control channel change Traffic channel B H A Mesh point F F Independent point Authorizing MP L Requesting MP G D Authorizing MP E I A MP may send requests to its mesh neighbors for permission to use a different control channel If the request is authorized, The requesting MP will tune its control radio to the requested channel If an authorizing MP has no other mesh neighbors, it will tune its control radio to the requested channel If an authorizing MP has other mesh neighbors it will tune a MT radio to the requested control channel In that case, if the authorizing MP has no additional MT radios, it will use the control channels for mesh traffic to its mesh neighbors Mathilde Benveniste, Avaya Labs

Forwarding a request May 2005 Forwarding MP Control channel Forwarding MP Authorizing MP Traffic channel B H 1 independent AP, L, operates in the mesh area on the same channel as the mesh control channel; MP G requests control channel change. Request is forwarded A Authorizing MP Mesh point F F Independent point L Requesting MP Authorizing MP G D Authorizing MP E I If a MP receives a request for control channel change, it may do one of the following: Accept the request Forward the request to all other neighbors, or Decline the request Mathilde Benveniste, Avaya Labs

Procedure for Splicing May 2005 A MP may request its mesh neighbors for permission to use a different control channel If a MP receives a request for control channel change, it may do one of the following: Accept the request Forward the request, or Decline the request A MP that accepts or declines a request or receives notice that a request it forwarded is accepted will notify the mesh neighbor from which it received the request A MP will consider its own or forwarded request accepted if all mesh neighbors to which it sent the request indicate that the request is accepted A request is authorized if it is considered accepted by the requesting MP If a request is authorized A MP that forwarded or submitted an authorized request will tune its control radio to the requested channel If a MP that accepted an authorized request has no mesh neighbors other the MP that sent the request, it will tune its control radio to the requested channel If an authorizing MP has mesh neighbors other than the MP that sent it the request it will tune a MT radio to the requested control channel and use it for control traffic In that case, if the authorizing MP has no additional MT radios, it will use the control channels for mesh traffic to its mesh neighbors If the request is not authorized, the requesting MP may resubmit a request for a different control channel Mathilde Benveniste, Avaya Labs