July 2009doc.: IEEE 802.11-09/0820r2
Resolutions to a number of MCCA related commentsDate: 2009-07-15
Author(s):
Name / Affiliation / Address / Phone / email
Dee Denteneer / Philips / HTC 37; 5656 AE Eindhoven The Netherlands /
GuidoHiertz / Philips / HTC 37; 5656 AE Eindhoven The Netherlands /
2. Normative References
Insert the following new normative references:
IETF RFC 5297, Synthetic Initialization Vector (SIV) Authenticated Encryption Using the Advanced Encryption Standard (AES), D. Harkins, October 2008 (status: informational).
IETF RFC 2409, The Internet Key Exchange (IKE), D. Harkins, D. Carrel, November 1998. (status: Standards Track)
3. Definitions
Change definition 3.42 Distribution system service (DSS) as indicated:
3.42 Distribution system service (DSS): The set of services provided by the distribution system (DS) that
3.42 enable the medium access control (MAC) to transport MAC service data units (MSDUs) between stations
3.42 (STAs) that are not in direct communication with each other over a single instance of the wireless medium
3.42 (WM). These services include transport of MSDUs between the access points (APs) of basic service sets
3.42 (BSSs) within an extended service set (ESS), transport of MSDUs between portals and BSSs within an ESS, transport of MSDUs between mesh stations (mesh STAs) of mesh basic services sets (MBSSs), and transport of MSDUs between STAs in the same BSS in cases where the MSDU has a multicast or
3.42 broadcast destination address or where the destination is an individual address and the STA is associated
3.42 with an AP. DSSs are provided between pairs of IEEE 802.11 MACs.
Delete definition 3.170 wireless distribution system (WDS)
Insert the following new definitions:
EDITORIAL NOTE—The subclause numbering of definition is of the form “3.s<x>” where <x> is an increasing number. These numbers need to be assigned before the sponsor ballot.
3.s1 candidate peer mesh station (STA): A neighbor mesh STA to which a peering has not been established but meets eligibility requirements to become a peer mesh STA.
3.s2 destination mesh STA: A mesh STA where a frame leaves the MBSS. A destination mesh STA may be a mesh STA that is the final destination of a frame or a proxy mesh STA that receives a frame from the MBSS and translates and forwards the frame to an entity outside of the MBSS.
3.s3 DTIM interval: The value, in Time Units, that is equivalent to the product of the Beacon Interval and the DTIM Period subfields specified within the TIM element in Beacon frames.
3.s4 link metric: A criterion used to characterize the performance/quality/eligibility of a link.
3.s5 mesh: A network consisting of two or more mesh stations (STAs) communicating via mesh services.
3.s6 mesh access point: A mesh station (STA) that is collocated with one or more access point(s).
3.s7 Mesh Awake Window: A period of time where the mesh STA operates in awake state after its Beacon or Probe Response frame transmission that contained the Mesh Awake Window element.
3.s8 mesh basic service set (MBSS): A basic service set (BSS) that forms a self-contained network of mesh stations (mesh STAs), and which may be used as a distribution system (DS).
3.s9 mesh BSS service area (MBSSSA): The area within which members (mesh stations) of a mesh basic service set (MBSS) may communicate.
3.s9 3.xy mesh coordination function (MCF): A coordination function that combines aspects of the contention-based and reduced contention access methods. The MCF includes the functionality provided by both enhanced distributed channel access (EDCA) and mesh controlled channel access (MCCA).
3.s10 Mesh Data Frame: A data frame with the FromDS and ToDS bits set to one that is transmitted from a mesh STA to a peer mesh STA.
3.s11 mesh coordinated channel access (MCCA): A coordination function for the MBSS.
3.s12 mesh coordinated channel access opportunity (MCCAOP): MCCAOP is aA period of time that is set up between a transmitter and a receiver.
3.s13 mesh link: A link from one mesh station (STA) to a neighbor mesh STA that has been established with the peering management protocol.
3.s14 mesh neighborhood: The set of all neighbor mesh STAs relative to a particular mesh STA.
3.s15 mesh path: A concatenated set of mesh links from a source mesh STA to a destination mesh STA.
3.s16 mesh path selection: The process of selecting a mesh path.
3.s17 mesh power mode: a mesh STA can select its power mode seen by neighboring peer mesh STA among active, light sleep and deep sleep modes. For peer mesh STAs the mesh power mode is peering specific.
3.s18 mesh services: The set of services that enable the creation and operation of an MBSS.
3.s19 mesh station (mesh STA): A station (STA) that implements the mesh facility. A mesh STA that operates in the Mesh BSS (MBSS) may provide the distribution services for other mesh STAs.
3.s20 neighbor mesh station (STA): A mesh STA that has a link with another mesh STA. Not all neighbor mesh STAs are peer mesh STAs.
3.s21 neighbor peer mesh station (STA): A mesh station (STA) to which a peering has been established and that has a link with its peer mesh STA.
3.s22 neighbor station (STA): From the point of view of a given STA, the set of neighbor STAs includes all STAs that it has a link with. In an MBSS, neighbor mesh STAs might not be peer mesh STAs.
3.s23 path metric: An aggregate multi-hop criterion used to characterize the performance/quality/eligibility of a mesh path.
3.s24 peering: A logical relationship from one mesh STA to another mesh STA that has been established with the mesh peering management protocol.
3.s25 peer mesh station (STA): A mesh STA to which a peering has been established. Not all peer mesh STAs are neighbor mesh STAs.
3.s26 peer service period (PSP):A peer service period is a contiguous period of time during which one or more individually addressed frames are transmitted between two peer mesh STAs and at least one mesh STA operates in power save mode. A peer service period is directional and may contain one or more TXOPs. One mesh STA transmits frames and initiates the termination of the peer service period. A mesh STA may have multiple peer service periods ongoing in parallel. At most one peer service period can be set up in each direction with each peer mesh STA.
3.s27 protocol instance: An execution of a particular protocol that consists of the state of the communicating parties as well as the messages exchanged.
3.s28 proxy mesh station (STA): A mesh STA that represents 802 entities outside the mesh basic service set (MBSS).
3.s29 source mesh STA: A mesh STA where a frame enters the MBSS. A source mesh STA may be a mesh STA that is the original source of a frame or a proxy mesh STA that receives a frame from an entity outside of the MBSS and translates and forwards the frame on a mesh path.
7. Frame formats
7.3.1.38 MCCAOP Reservation field
The MCCAOP Reservation field is a 4 octet field specifying the starts of a series of MCCAOPs, relative to the DTIM interval of the reporting mesh STA, and their (common) duration. The MCCAOP Reservation field consists of 3 subfields and its format is illustrated in Figures12 (MCCAOP Reservation field).
MCCAOPDuration / MCCAOP
Periodicity / MCCAOP Offset
Octets: 1 / 1 / 2
Figure s12—MCCAOP Reservation field
The MCCAOP Duration field specifies the duration of the MCCAOPs in multiples of 32µs.
The MCCAOP Periodicity field is an eight bit unsigned number. A positive non-zero Periodicity field specifies the number of MCCAOPs in the DTIM interval. These MCCAOPs are repeated in all DTIM intervals until the MCCAOP Reservation is torn down. A value of zero indicates a non-repeated MCCAOP in the DTIM interval following the setup.
The MCCAOP Offset field specifies the beginning of the MCCAOP relative to the beginning of each subinterval. The value is specified in multiples of 32 µs.
An example of periodicity, duration, and offset values for an MCCAOP Reservation field is shown in Figures13 (Values for Periodic MCCAOP Info field for an example MCCAOP Reservation). In this particular example, the periodicity equals four, so that there are four MCCAOPs within the DTIM interval. As further illustrated in the figure, the offset value indicates the start of the MCCAOPs relative to the beginning of these subintervals.
Figure s13—Example MCCAOP ReservationValues for Periodic MCCAOP Info field for an example MCCAOP Reservation7.3.2 Information elements
7.3.2.95 MCCAOP Setup Request element
The MCCAOP Setup Request element is used to setup one or more MCCAOPs. This information element is transmitted in individually addressed MCCA action frames. The mesh STA transmitting the MCCA Setup Request element is the MCCAOP owner of the MCCAOPs defined in this setup. The receivers of the MCCAOP Setup Request are the MCCAOP responders.The MCCAOP Setup Request element is used to setup one or more MCCAOPs, identified by a single MCCAOP Reservation ID, between an MCCAOP owner and one or more MCCAOP responders. This information element is transmitted in individually addressed MCCA action frames by the MCCAOP owner to each of the MCCAOP responders. The format of the information element is as shown in Figures31 (MCCAOP Setup Request element
).
Reservation ID / MCCAOP
Reservation
Octets: 1 / 1 / 1 / 4
Figure s31—MCCAOP Setup Request element
The Element ID is set to the value given in Table7-26 (Element IDs) for this information element. The Length is set to 5 octets.
The MCCAOP Reservation ID field is an eight bit unsigned number that represents the ID for the MCCAOP reservation. It is determined by the MCCAOP owner. When used in combination with the MAC address of the MCCAOP owner, the MCCAOP Reservation ID uniquely identifies the MCCAOP Reservation.
If this MCCAOP Setup Request is for an individually addressed transmission, the MCCAOP Reservation ID is between 0 and 127 and the Setup Request is transmitted in an individually addressed frame to the intended responder. If this MCCAOP Setup Request is for a group addressed transmission, the MCCAOP Reservation ID is between 128 and 254 and the Setup Request is transmitted in individually addressed frames to each of the intended responders.
The MCCAOP Reservation field specifies the starts and duration of a series of MCCAOPs, as described in 7.3.1.38 (MCCAOP Reservation field).
7.3.2.96 MCCAOP Setup Reply element
The MCCAOP Setup Reply element is used to reply to an MCCAOP Setup Request. Its format is as shown in Figures32 (
MCCAOP Setup Reply element
).
The Element ID is set to the value given in Table7-26 (Element IDs) for this information element. The length is set to 2 or 6 octets.
Element ID / Length / MCCAOPReservation ID / MCCA Reply Code / MCCAOP
Reservation
Octets: 1 / 1 / 1 / 1 / 4
Figure s32—MCCAOP Setup Reply element
The MCCAOP Reservation ID field is an eight bit unsigned number that represents the ID for the requested series of MCCAOPs. It is determined by the MCCAOP owner. When used in combination with the MAC address of the MCCAOP owner, the MCCAOP Reservation ID uniquely identifies the series ofone or more MCCAOPs. If this MCCAOP Setup Request is for an individually addressed transmission, the MCCAOP Reservation ID is between 0 and 127. If this MCCAOP Setup Request is for a group addressed transmission, the MCCAOP Reservation ID is between 128 to 254.
The MCCA reply Code field is defined in 7.3.2.96.1 (MCCA Reply Code field).
The MCCAOP Reservation field includes an alternative to the MCCAOP Reservation specified in the MCCAOP Setup Request message. Its format is described in 7.3.1.38 (MCCAOP Reservation field). This field is an optional field and is only included and interpreted when the reply code indicates rejection.
7.3.2.96.1 MCCA Reply Code field
The MCCA Reply Code field is a one Octet field that contains the responses used in an MCCAOP Setup Reply element. The reply codes are defined in Tables9 (MCCA Reply codes)
Table s9—MCCA Reply codesMCCA Reply code / Meaning
0 / Accept
1 / Reject: MCCAOP Reservation conflict
2 / Reject: MAF limit exceeded
Other / Reserved
7.3.2.97 MCCAOP Advertisements element
The MCCAOP Advertisements element is used by a mesh STA to advertise its MCCA state to its neighbors. This information element can be carried in selected Beacon frames with a chosen frequency. This information element is also transmitted in an MCCA action frame. The format of the information element is as shown in Figures33 (MCCAOP Advertisements element
).
Information / TX-RX Times Report / Broadcast Times Report / Interfering Times Report
Octets: 1 / 1 / 2 / variable / variable / variable
Figure s33—MCCAOP Advertisements element
The Element ID is set to the value given in Table7-26 (Element IDs) for this information element. The Length is set to 1 to 255 octets.
The MCCA Information field is a field of 2 octets. It is described in 7.3.2.97.2 (MCCA Information field).
The TX-RX Times Report field is a variable length field that contains an MCCA MCCAOP Reservation Report field as described in 7.3.2.97.1 (MCCAOP Reservation Report field). Through the TX-RX Times Report field, a mesh STA advertises the MCCAOPs in which it is involved as an MCCAOP owner or an MCCAOP responder and in which individually addressed frames are transmitted.
The Broadcast Times Report field is a variable length field that contains an MCCA MCCAOP Reservation Report field as described in 7.3.2.97.1 (MCCAOP Reservation Report field). Through the Broadcast Times Report field, a mesh STA advertises the MCCAOPs in which it is involved as an MCCAOP owner or an MCCAOP responder and in which group addressed frames are transmitted. These reports optionally include known and otherwise un-advertised transmission and reception times of the mesh STA besides MCCAOPs, for example, its HCCA times.
The Interfering Times Report field is a variable length field that contains an MCCA MCCAOP Reservation Report field as described in 7.3.2.97.1 (MCCAOP Reservation Report field). Through the Interfering Times Report field, a mesh STA reports the TX-RX and Broadcast Times of its neighbors, excluding its own TX-RX and Broadcast times.
7.3.2.97.1 MCCAOP Reservation Report field
The MCCAOP Reservation Report field is a variable length field that is used to report a number of MCCAOP Reservations. The field consists of a variable number of subfields and its format is illustrated in Figures34 (MCCAOP Reservation Report field)
Number of Reported MCCAOP Reservations / MCCAOPReservation 1 / ... / MCCAOP
Reservation Nn
Octets: 1 / 4 / 4
Figure s34—MCCAOP Reservation Report field
The Number of Reported MCCAOP Reservations is a field of one octet with a positivean unsigned integer that specifies the number, n, of MCCAOP Reservations reported in this field.
The MCCAOP Reservation 1 through MCCAOP Reservation n fields specify the MCCAOP Reservations reported. Each field is of length 4 Octets and contains an MCCAOP Reservation field, whose format is shown in Figures12 (MCCAOP Reservation field) in 7.3.1.38 (MCCAOP Reservation field).
7.3.2.97.2 MCCA Information field
The MCCA Information field is a field of length 2 Octets that is used to provide information on the MCCAOP Reservations. The field consists of six subfields and its format is illustrated in Figures35 (
MCCA Information field
).
MCCA Access
Fraction / MCCA Access
Fraction Limit / TX-RX Report
Present / Broadcast Report
Present / Interfering Report
Present / Partial Report
Bits: 8 / 4 / 1 / 1 / 1 / 1
Figure s35—
Figure s35—MCCA Information field
The MCCA Access Fraction is an eight bit unsigned number field and the MCCA Access Fraction Limit field is a 4 bit unsigned number field. The MCCA Access Fraction denotes a positive fraction of the MCCA Access Fraction Limit expressed in units of 1/255. The MCCA Access Fraction Limit denotes a positive fraction of the DTIM interval length expressed in units of (1/16). The MCCA Access Fraction field represents the current value of MCCA Access Fraction at the mesh STA rounded down (floor) to the nearest multiple of (1/256). The MCCA Access Fraction Limit field represents the maximum MCCA access fraction allowed at the mesh STA. This number is always a multiple of (1/16).
The TX-RX Report Present is a one bit field. It is set to 1 if a TX-RX Report is present in the MCCAOP Advertisement and set to 0 if no TX-RX Report is present.
The Broadcast Report Present is a one bit field. It is set to 1 if a Broadcast TX-RX Report is present in the MCCAOP Advertisement and set to 0 if no Broadcast TX-RX Report is present.
The Interfering Report Present is a one bit field. It is set to 1 if an Interfering Times Report is present in the MCCAOP Advertisement and set to 0 if no Interfering Times Report is present.
The Partial Report field is a one bit field. It is set to 0 if the Advertisement element includes all known reservations and it is set to 1 if the Advertisement element does not include all known reservations.
7.3.2.98 MCCAOP Reservation Teardown element
The MCCAOP Reservation Teardown element is used to announce the teardown of an MCCAOP Reservation. Its format is shown in Figures36 (MCCAOP Reservation Teardown element
).
Reservation ID / MCCAOP
Owner
Octets: 1 / 1 / 1 / 6
Figure s36—MCCAOP Reservation Teardown element
The Element ID is set to the value given in Table7-26 (Element IDs) for this information element. The Length is variable and set to 1 or 7 octets.
An MCCAOP Reservation Teardown element is transmitted by either the MCCAOP owner or the MCCAOP responder of a MCCAOP Reservation to tear down the MCCAOP Reservation. The MCCAOP Owner field is an optional field that indicates the MAC address of the MCCAOP owner. This field is only included if the information element is transmitted by the MCCAOP responder. The MCCAOP Reservation Teardown element is transmitted in Beacon frames or group addressed MCCA action frames.
7.4 Action frame format details
.
7.4.16 Mesh Resource Coordination action frame details
Action frame formats for management of Mesh Resource Coordination are defined in this subclause.
An Action field, in the octet field immediately after the Category field, differentiates the frame format. The Action field values associated with each frame format are defined in Tables22 (Mesh Resource Coordination Action field values).
Table s22—Mesh Resource Coordination Action field valuesAction field value / Description
0 / Congestion Control Notification
1 / MCCA Setup Request
2 / MCCA Setup Reply
3 / MCCAOP Advertisement Request
4 / MCCAOP Advertisements
5 / MCCAOP Reservation Teardown
6 / TBTT Adjustment Request
7 / Mesh Channel Switch Announcement
8-255 / Reserved
7.4.16.1 Congestion Control Notification frame format