doc.: ieee 802.11-10/0205r2 · web view802.11 tgs submission on mesh channel switch announcement...

March 2010 doc.: IEEE 802.11-10/0205r2

IEEE P802.11Wireless LANs

802.11 TGs Submission on Mesh Channel Switch Announcement Cleanup.

Date: 2010-03-18

Author(s):Name Company Address Phone email

Ashish Shukla Marvell

1st Floor, Muttha Tower, Don Bosco Marg, Yerwada, Pune,

India.

+91-20-40130016

[email protected]

Submission page 1 Ashish Shukla, Marvell

AbstractThis submission contains normative text related to extension of Channel Switch Procedures defined in IEEE 802.11, 2007 std., IEEE 802.11y, and IEEE 802.11n specification for the use in MBSS. Thanks to Kazuyuki Sakoda for the initial review and comments.

This also addresses the following CIDs received on LB159 of IEEE 802.11s 4.0 draft:2170, 2226, 2227, 2228, 2279, 2280, 2281, 2282, 2342, 2351, 2362, 2387, 2388, 2392, 2393, 2493, 2494, 2495, 2496, 2506, 2524, 2525, 2526, 2639, 2750, 2751, 2752, 2753, 2754, 2755, 2756, 2757, 2758, 2759, 2760, 2761, 2762, 2763, 2764, 2765, 2766, 2768, 2793.

The text is aligned with P802.11-REVmb/D2.01 and P802.11s/D4.01.

March 2010 doc.: IEEE 802.11-10/0205r2

CID Comment / Explanation Recommended Change Resolution Code

Resolution Notes

2170 The MCCAOP and the MAF are derived from timing based on the DTIM interval, not on the channeld width (20 or 20/40MHz). Therefore, the MAF will not change and not cross the MAF Limit.

Delete paragraph at page 132 lines 38-40. Concatenate the paragraphs at lines 35-36 and 42-43.

Accept Submission 0205r0 resolves this.

2226 The current description of the Channel Switch protocol will lead to deadlocks. This is not acceptable.

make the Channel Switch protocol safe.

Reject Commenter is encouraged to help identify the problem assuming submission 0205r0.

2227 A mesh STA that initiates the generation of a frame usually takes the values of local attributes and puts them into the corresponding fields of the frame. This paragraph describes this the other way round, which is strange.

Rewrite the paragraph so that the fields of the Mesh Channel Switch Announcement element are set with values from local attributes.

Counter Submission 0205r0 resolves this issue.

2228 This clause should be moved to the corresponding clause for channel switching in the base standard IEEE 802.11-2007.

as in comment Accept Submission 0205r0 resolves this issue.

2279 "The decision to accept a …" should be "the decision method to accept a …"

per comment Counter Submission 0205r0 resolves this issue.

2280 Two sentence beginning "The decision to accept a…" are redundant to the sentences beginning on line 48.

Remove redundant sentences.


2281 In a regulatory class where DFS is required, there should be a sentence about setting the timer value to less than the maximum needed to meet regulatory requirements, and not accepting a Switch Announcement with the timer value greater than the maximum time allowed to leave a radar channel. Without timer value limit requirements in the standard, the mesh cannot assure it meets regulatory requirements.

Add language requiring the entire mesh to channel switch to meet regulatory requirements, and not accept channel switch announcements with too large switch count values.

Reject The base standard and 11y extended channel switch do not impose any such guidelines on maximum time for channel switch during BSS channel switch. MBSS channel switch is an extension of this. Standard provides mechanism to implement desired policy.


March 2010 doc.: IEEE 802.11-10/0205r2

Please see submission 0205r0 as well.

2282 "the mesh STA that initiates the channel switch attempt across the regulatory class shall verify that all of its neighborhood peer mesh STAs support the new regulatory class by checking neighbor mesh STA's Supported Regulatory Classes element." What messages are used to fetch the neighbor's IEs?

Describe what messages each mesh STA has to send to every neighbor mesh STA in 11C.4 Authenticated Mesh Peering Exchange or a new message exchange description, including gathering Country information and SupportedRegulatoryClasses.

Reject It was already fixed in 4.0 draft spec, 11C.6.3 11C.6.3 Channel Switch across a regulatory class.

2342 The word "Reason" promises to provide some kind of explanation why something occured. In fact, a single bit cannot represent a reason.

Rename all occurences of "Reason" with "Enforced" since the current text describes that the current "Reason" code indicates a channel switch due to regulatory requirements.

Counter Submission 0205r0 adds 2 octects Reason Code for more flexibility.

2351 The last sentence prohibits to switch channel more than once.

Add "until it determines the need to switch the channel again." to the end of this paragraph.


2362 Typically fields are 2 octets in length, not 2 octets long

Change as commented. Accept Submission 0205r0 resolves this issue.

2387 Unnecessary repetition. The sentence in line should read:" …, the mesh STA should inform its peer mesh STAs."

Accept Submission 0205r0 resolves this issue.

2388 The channel change from 20/40 to 20 MHz does not change MCCAOP reservations. MCCAOP reservations are time specific reservations and their durations do not increase if the channel is changed

Change the lines 39-40 to state that mesh STAs may need to perform new MCCA reservations to maintain the same transmission capacity. Remove MAF specific parts.

Accept Duplicate of 2170

2392 The MBSS Channel switching is not really needed to satisfy the regulatory requirements. Rather it is signaling and coordination mechanism that tries to move all mehs STAs to the same new operating channel

Remove regulatory requirements from MBSS switching. Define that mechanism is coordination mehcanism as commented.


2393 The guidance to select random number is not needed and just confuses the reader. It is just a random number.

Remove the sentence: " The random number…".


2493 Mesh channel switch announcement element can take advantage of already existing Extended Channel Switch Announcement and can avoid redefining the most of the fields already there in Extended Channel Switch Announcement element.

A proposal can be submitted if required


2494 For 20/40 MHz transition it might be useful to include Secondary Channel


Accept Submission 0205r0


March 2010 doc.: IEEE 802.11-10/0205r2

offset element information as well. resolves this issue.

2495 This element is propagated by peer Mesh STA and therefore to limit the scope of the propagation a field like TTL might be useful.



2496 An MLME-SAP primitive to perform Mesh Channel Switch might be useful



2506 For HT 40MHz capable mesh STAs it's useful to include Secondary Channel offset element in this. Apart from this, a TTL value to limit the propagation of this frame, an MLME-SAP may defined.



2524 It may be useful to include the following at the end:"After switching channel, mesh STA shall perform a clear channel assessment (CCA) on the target channel, until a frame sequence is detected by which it can correctly set its NAV, or until a period of time equal to ProbeDelay has transpired.The first transmission on the target channel shall be preceded by a random backoff."

As suggested in the comment.


2525 When dot11MeshForwarding is disabled, it's not clear whether mesh STA should be allowed to propagate Mesh Channel Switch announcement or not?

Clarify. Reject Mesh Channel Switch is needed to ensure MBSS connectivity.

2526 There is nothing to limit the scope of propagation of Mesh Channel Switch Announcement frame. A field such as TTL might be added to limit the scope.



2639 Refine the text here. Replace "If a mesh STA detects the need to switch the channel (e.g., due to regulatory requirement for radar avoidance), the mesh STA should inform peer mesh STAs to which a mesh link has been established.Once the mesh STA identifies the candidate channel to switch its channel to, it shall initiate the Channel Switch protocol described in 11C.6 (MBSS channel switching)."with "If a mesh STA detects the need to switch the channel (e.g., due to regulatory



March 2010 doc.: IEEE 802.11-10/0205r2

requirement for radar avoidance), it shall identify the candidate channel to switch its channel to and initiate the Channel Switch protocol described in 11C.6 (MBSS channel switching)."

2750 "The random value shall be selected in a manner…"

Vague and unactionable -- if someone does not know how to generate a random number, this text will not help. Delete the sentence.


2751 We've had success dividing up clauses into "conditions for sending this" and "actions to be taken when receiving that".

This clause should be subdivided into "conditions for sending" and "actions after receiving" like other elements in the mesh amendment. There is a clear transition at line 47 page 167.


2752 "in case the mesh STA accepts" -- we have another opportunity to add conditions for processing the channel switch announcement. See also "In case the Precedence".

Clearly identify the conditions for processing a channel switch announcement. Wording such as "may be used in deciding whether to accept or ignore this channel switch" is too vague and must be replaced with the actual decision-making information.


2753 "shall be set as follows" and "shall act as follows" doesn't indicate what "follows" mean. Is it the whole clause, the whole amendment, the rest of the text that the reader will encounter until the end of time?

If using "as follows", please use clear indentation information such as bullet lists. Lines 17 and 53


2754 "Thedecision to accept a Mesh Channel Switch Announcement is beyond the scope of this standard."

The same sentence appears just 10 lines above



If that's the case, what is the purpose of the Silence field? Is it asking politely not to transmit further? Or does it means that it won't reply? Please clear the ambiguity by stating what the expection from the Silence field is. Or remove it…



March 2010 doc.: IEEE 802.11-10/0205r2

2756 "The Silence field is set to 1 when the mesh STA asks neighboring mesh STAs not to transmit further dataframes on the current channel until the scheduled channel switch. The silence field is set to 0 otherwise".

This text appears on page 46 line 28, page 167 line 27, page 168 line 1. Surely there is some unecessary repetition.

I suggest using tables to describe the content of the channel switch announcement based on the different conditions. Just like the HWMP elements.


2757 "The information in the Mesh Channel Switch Mode may also be used for this decision." Which decision? Which information? Does "may" means this is only advice?

Advice not needed. Delete sentence or provide normative text.


2758 "In case the mesh STA accepts a channel switch, it shall transmit a Channel Switch Announcement frame toeach of its peer mesh STAs and include the Mesh Channel Switch Announcement element in its Beacon andProbe Response frames.": this is exactly the same behaviour for the initial switch announcement

If the result is the same, then only specify it once…


2759 "The fields in the Mesh Channel Switch Announcement are set to values identical tothose in the received Mesh Channel Switch Announcement frame, except for"

"except for" is not really a great way to describe how to fill an element. If we used tables, then we would enumerate the fields and not have to point out the differences. See HWMP elements.


2760 "Upon receipt of the Channel Switch Announcement" -- OK, the entire paragraph assumes "upon receipt" do we really have to repeat it?

Remove "Upon receipt of the Channel Switch Announcement"


2761 "The channel switch attempt initiator should set the Channel Switch Count so that its channel switch attemptcan be propagated throughout the mesh before it leaves the channel." this sounds like a summary of everything that was written in the previous two pages. It is also unactionable.

Delete sentence Counter Submission 0205r0 resolves this issue.

2762 After reading the channel switch protocol, I do not see any indication of how the Channel Switch Precedence is supposed to be used.



You say that, but you also write "In case the Precedence Value in the received Mesh Channel Switch

Counter Submission 0205r0 resolves this issue


March 2010 doc.: IEEE 802.11-10/0205r2

Announcement frame is lower than or equal to its Current Precedence Value, the received Mesh ChannelSwitch Announcement shall be ignored". So it doesn't seem to be out of scope! Which one is true?

2764 "A channel switch attempt is identified by these parameters."

Fascinating.How does that help?

Delete sentence Accept Please see submission 0205r0.

2765 "When theMesh Channel Switch Timer reaches zero, the mesh STA shall switch to the new channel."

There is no indication (other than "and count it down" on the following page") that there is a countdown

Identify the countdown in a slightly more obvious manner. A table format will probably make it more obvious that the timer is first equal to the count and then it decreases in value.

Counter Submission 0205r0

2766 "does not tear down mesh peering" "does not tear down mesh peerings"

Accept Submission 0205r0

2768 "the mesh STA that initiates the channel switchattempt across the regulatory class shall verify that all of its neighboring peer mesh STAs support the newregulatory class by checking neighbor mesh STA's Supported Regulatory Classes element."

OK, it checks. And then what? There is no action!

Make this non-normative, and indicate that it's probably better not to switch regulatory class unless necessary.

Counter Submission 0205r0

2793 "A STA shall set dot11SpectrumManagementRequired to true before associating with an infrastructure BSS, IBSS or MBSS in which…" "association" is not defined in the MBSS. Correct the text.

As in comment. Counter Submission 0205r0 resolves this issue.


March 2010 doc.: IEEE 802.11-10/0205r2

Summary of the major changes:1. Restructure MBSS channel switch procedure, which is now merged with baseline channel

switch specification.2. Reusing (Extended) Channel Switch Announcement element and frame together with a

new Mesh Channel Switch Parameters element for MBSS channel Switch.3. More control on the Channel Switch propagation by inclusion of Time to Live field.4. Extended Reason bit to 2 octets Reason Code field to indicate the possible reason for

Channel Switch.5. MLME-SAP primitive extensions for MBSS channel Switch

Apply the suggested changes here:


March 2010 doc.: IEEE 802.11-10/0205r2

7 Beacon frame format

Insert the following additional row (preserving their order) in Error: Reference source notfound just before the Vendor Specific elemen:

T Beacon frame bodydocument.doc

Order Information Notes

56 Mesh Channel Switch Parameters

The Mesh Channel Switch Parameters element is optionally present when dot11MeshActivated is true and either Channel Switch Annoucement element or Extended Channel Switch Announcement element is present.

7 Probe Response frame format

Insert the following additional row (preserving their order) in before the last row of ProbeResponse frame bodydocument.doc just before the Vendor Specific element:

T Probe Response frame bodydocument.doc


53 Mesh Channel Switch Parameters

The Mesh Channel Switch Parameters element is optionally present when dot11MeshActivated is true and either Channel Switch Annoucement element or Extended Channel Switch Announcement element is present.

7 Reason Code field

Insert the following rows into Reason codesdocument.doc and change the last row (Reserved) as shown.

T Reason codesdocument.doc


March 2010 doc.: IEEE 802.11-10/0205r2

Reason code Meaning

< “MESH-PEERING-CANCELLED”. SME cancels the mesh peering instance with the reason other than reaching the maximum number of peer mesh STAs

< “MESH-MAX-PEERS”. The mesh STA has reached the supported maximum number of peer mesh STAs

< “MESH-CONFIGURATION-POLICY-VIOLATION”. The received information violates the Mesh Configuration policy configured in the mesh STA profile

< “MESH-CLOSE-RCVD”. The mesh STA has received a Mesh Peering Close message requesting to close the mesh peering.

< “MESH-MAX-RETRIES”. The mesh STA has re-sent dot11MeshMaxRetries Mesh Peering Open messages, without receiving a Mesh Peering Confirm message.

< “MESH-CONFIRM-TIMEOUT”. The confirmTimer for the mesh peering instance times out.

< “MESH-INVALID-GTK”. The mesh STA fails to unwrap the GTK or the values in the wrapped contents do not match

< “MESH-INCONSISTENT-PARAMETERS”. The mesh STA receives inconsistent information about the mesh parameters between Mesh Peering Management frames

< “MESH-INVALID-SECURITY-CAPABILITY”. The mesh STA fails the Authenticated Mesh Peering Exchange because due to failure in selecting either the pairwise ciphersuite or group ciphersuite

< “MESH-PATH-ERROR-UNSPECIFIED”. The mesh STA sends PERR with no specific reason for the unreachable destination contained in the PERR.

< “MESH-PATH-ERROR-NO-FORWARDING-INFORMATION”. The mesh STA does not have forwarding information for this destination.

< “MESH-PATH-ERROR-DESTINATION-UNREACHABLE”. The mesh STA finds destination unreachable.

< “MAC-ADDRESS-ALREADY-EXISTS-IN-MBSS”. The Deauthentication frame was sent because the MAC address of the STA already exists in the mesh BSS. See Error: Reference source not found.

< ANA 16> “MESH-CHANNEL-SWITCH-REGULATORY-REQUIREMENTS”. The mesh STA performs channel switch to meet regulatory requirements.

<ANA 17> “MESH-CHANNEL-SWITCH-UNSPECIFIED”. The mesh STA performs channel switch with unspecified reason.

+1 40-65535 Reserved

E The Mesh reason codes need to be allocated before sponsor ballot by ANA.


March 2010 doc.: IEEE 802.11-10/0205r2

7 Information elements

Insert the following rows (ignoring the header row and footer note) in Element IDsdocument.doc—Element IDs in the correct position to preserve ordering by the “Element ID” column and update the “Reserved” range of codes appropriately.

Modify the row of Table 7-26 Elements IDs containing Mesh Channel Switch Annoucement as shown below:

T Element IDsdocument.doc

Information element Element ID

Total length of element in

octets including the

Type and Length octets

Extensible

Mesh Channel Switch Announcement Parameters Error: Reference source not found

< 98 Yes

7.3.2.20 Channel Switch Announcement element

Modify the first paragraph of 7.3.2.20 as shown below:

The Channel Switch Announcement element is used by an AP in a BSS, or a STA in an IBSS, or a mesh STA in an MBSS to advertise when it is changing to a new channel and the channel number of the new channel. The format of the Channel Switch Announcement element is shown in Figure 7-57 (Channel Switch Announcement element format).

Modify the fifth paragraph of 7.3.2.20 as shown below:For non-mesh STAs, tThe Channel Switch Count field either is(#29) set to the number of TBTTs until the STA sending the Channel Switch Announcement element switches to the new channel or is(#29) set to 0. A value of 1 indicates that the switch occurs(#29) immediately before the next TBTT. A value of 0 indicates that the switch occurs(#29) at any time after the frame containing the element is transmitted.For mesh STAs, the Channel Switch Count field is encoded as an octet with bits 6 to 0 are set to the time, in units of 2TU when MSB (bit 7) set to 0, or in units of 100TU when MSB (bit 7) set to 1, until the mesh STA sending the Channel Switch Announcement element switches to the new channel. A value of 0 for the bits 6 to 0 indicates that the switch occurs at any time after the frame containing the element is transmitted. For example, a 200 TU channel switch time is encoded as X'82' and a 10TU channel switch time is encoded as X'05'.

7.3.2.20a Secondary Channel Offset element

Modify the first paragraph of 7.3.2.20a as shown below:


March 2010 doc.: IEEE 802.11-10/0205r2

The Secondary Channel Offset element is used by an AP in a BSS, or a STA in an IBSS, or a mesh STA in an MBSS together with the Channel Switch Announcement element when changing to a new 40 MHz channel. The format of the Secondary Channel Offset element is shown in Figure 7-57a (Secondary Channel Offset element format).

7.3.2.53 Extended Channel Switch Announcement element(11y)


The Extended Channel Switch Announcement element is used by an access point (AP) in a basic service set (BSS), or a STA in an independent basic service set (IBSS), or a mesh STA in an MBSS to advertise when the BSS, or MBSS is changing to a new channel or a new channel in a new regulatory class. The announcement includes both the regulatory class and the channel number of the new channel. The element is present only when an extended channel switch is pending. The format of the Extended Channel Switch Announcement element is shown in Figure 7-95o12 (Extended Channel Switch Announcement element format(#1248)).

Modify the third paragraph of 7.3.2.53 as shown below:

The Channel Switch Mode field indicates any restrictions on transmission until a channel switch. An AP in a BSS or a STA in an IBSS sets the Channel Switch Mode field to either 0 or 1 on transmission as specified in 11.9.7.1 (Selecting and advertising a new channel in an infrastructure BSS) and 11.9.7.2 (Selecting and advertising a new channel in an IBSS). The Channel Switch Mode field is reserved in an MBSS.

Modify the last paragraph of 7.3.2.53 as shown below:

For non-mesh STAs, tThe Channel Switch Count field indicates either the number of target beacon transmission times (TBTTs) until the STA sending the Extended Channel Switch Announcement element switches to the new channel or a value of zero. A value of one indicates that the switch occurs immediately before the next TBTT. A value of zero indicates that the switch occurs anytime after the frame containing the element is transmitted.For mesh STAs, the Channel Switch Count field is encoded as an octet with bits 6 to 0 are set to the time, in units of 2TU when MSB (bit 7) set to 0, or in units of 100TU when MSB (bit 7) set to 1, until the mesh STA sending the Channel Switch Announcement element switches to the new channel. A value of 0 for the bits 6 to 0 indicates that the switch occurs at any time after the frame containing the element is transmitted. For example, a 200 TU channel switch time is encoded as X'82' and a 10TU channel switch time is encoded as X'05'.

Delete 7.3.2.100 Mesh Channel Switch Announcement completely:

7 Mesh Channel Switch Announcement element

The Mesh Channel Switch Announcement element is used by a mesh STA in an MBSS to advertise to other mesh STAs when it is changing to a new channel in the current regulatory class or a new channel in a new regulatory class. The announcement includes the regulatory class, the channel number and precedence value of the new channel


March 2010 doc.: IEEE 802.11-10/0205r2

(See 11C.6 (MBSS channel switching)). The format of the Mesh Channel Switch Announcement element is shown in Error: Reference source not found.

Element ID

Length Channel Switch Mode

New Regulatory

Class

New Channel Number

Precedence Value

Channel Switch Count

Octets: 1 1 1 1 1 2 2

F Mesh Channel Switch Announcement element

The Element ID is set to the value given in Element IDsdocument.doc for this element.

The Length field is set to 7.

The Channel Switch Mode field indicates the attribute of this channel switch attempt. The details of the Channel Switch Mode field are shown in Flags field.

B0 B1 B2 B3 B7

Silence Initiator Reason Reserved

Bits: 1 1 1 5

F

F Channel Switch Mode field

The Silence field is set to 1 when the mesh STA asks neighboring mesh STAs not to transmit further data frames on the current channel until the scheduled channel switch. The silence field is set to 0 otherwise.

The Initiator field is set to 1 when the mesh STA initiates this channel switch attempt, and set to 0 when this channel switch attempt is initiated by another mesh STA and propagated by the current mesh STA.

The Reason field is set to 1 when this channel switch attempt is triggered by the spectrum usage rule imposed by the regulatory domain, and set to 0 otherwise.

The New Regulatory Class field is set to the regulatory class index value defined in Annex J to which the mesh STA is moving.

The New Channel Number field is set to the channel number to which the mesh STA is moving.

The Precedence Value field is 2 octets long and contains an unsigned integer that is set to a random value.

The Channel Switch Count field is 2 octets long and contains an unsigned integer. It is set to the duration in TUs (rounded down to the next integer) until the mesh STA sending the Mesh Channel Switch Announcement element switches to the new channel. A value of 0 indicates that the switch occurs at any time after the frame containing the element is transmitted.

The Mesh Channel Switch Announcement element is included in Mesh Channel Switch Announcement frames.


March 2010 doc.: IEEE 802.11-10/0205r2

The detailed usage of the Mesh Channel Switch Announcement element is described in 11C.6 (MBSS channel switching).

Insert 7.3.2.100 Mesh Channel Switch Parameters element as shown below:

7 Mesh Channel Switch Parameters element

The Mesh Channel Switch Parameters element is used together with Channel Switch Announcement element and Extended Channel Switch Announcement element by a mesh STA in an MBSS to advertise to other mesh STAs when it is changing to a new operating channel and/or regulatory class. The format of the Mesh Channel Switch Parameters element is shown in Error: Reference source not found.

Element ID

Length Time to Live

Flags Reason Code

Precedence Value

Octets: 1 1 1 1 2 2

F Mesh Channel Switch Parameters element

The Element ID is set to the value given in Element IDsdocument.doc for this element.

The Length field is set to 6.

The Time to Live field is coded as an unsigned integer and indicates the remaining number of hops allowed for this element

The Flags field indicates the attribute of this channel switch attempt. The details of the Flags field are shown in Flags field.

B0 B1 B2 B3 B7

Transmit Restrict

Initiator Reason Reserved

Bits: 1 1 1 5

F Flags field

The Transmit Restrict subfield is set to 1 when the mesh STA asks neighboring peer mesh STAs not to transmit further frames except frames containing Mesh Channel Switch Parameters element on the current channel until the scheduled channel switch. The Transmit Restrict subfield is set to 0 otherwise.

The Initiator subfield is set to 1 when the mesh STA initiates this channel switch attempt, and set to 0 when this channel switch attempt is initiated by another mesh STA and propagated by the current mesh STA.


March 2010 doc.: IEEE 802.11-10/0205r2

The Reason subfield indicates the validity of the Reason Code field. It is to 1 if the Reason Code field is valid, and set to 0 otherwise. When the Reason subfield is 0, the content of the Reason Code field is reserved.

The Reason Code field specifies the reason for Mesh Channel Switch. The Reason Code is defined in 7.3.1.7 (Reason Code field). The contents of Reason Code fiels is valid only when Reason subfield of Flags field is set to 1, and is reserved otherwise.

The Precedence Value field is coded as unsigned integer and is set to a random value in the range 0 to 65535.

The Mesh Channel Switch Parameters element is included in Channel Switch Announcement frames, as described in 7.4.1.5 (Channel Switch Announcement frame format), and Extended Channel Switch Announcement frames, as described in 7.4.7.6 Extended Channel Switch Announcement frame format. During MBSS Channel Switch the Mesh Channel Switch Parameters element may be included in Beacon frames, as described in 7.2.3.1 (Beacon frame format), and Probe Response frames, as described in 7.2.3.9 (Probe Response frame format) until scheduled channel switch.

7.4.1.5 Channel Switch Announcement frame format


The Channel Switch Announcement frame uses the Action frame body format and is transmitted by an AP in a BSS, or a STA in an IBSS, or a mesh STA in an MBSS to advertise a channel switch. The format of the Channel Switch Announcement frame body is shown in Figure 7-100 (Channel Switch Announcement frame body format).

Replace Figure 7-100 with the following figure:

Category Action Value

Channel SwitchAnnouncement element

Secondary Channel Offset

element

Mesh Channel Switch Parameters element

Octets: 1 1 5 3 6

Figure 7-100—Channel Switch Announcement frame body format

Insert the following paragraph at the end of 7.4.1.5:

Mesh Channel Switch Parameters element is defined in 7.3.2.100 (Mesh Channel Switch Parameters element). This element is present when a mesh STA performs MBSS channel switch. The Mesh Channel Switch Parameters element is not included for channel switch other than MBSS.

7.4.7.6 Extended Channel Switch Announcement frame format(11y)



March 2010 doc.: IEEE 802.11-10/0205r2

The Extended Channel Switch Announcement frame is transmitted by an AP in an infrastructure BSS, or a STA in an IBSS, or a mesh STA in an MBSS to advertise a channel switch. The format of the Extended Channel Switch Announcement frame body is shown in Figure 7-101h4 (Extended Channel Switch Announcement frame body format(#1248)).

Replace Figure 7-101h4—Extended Channel Switch Announcement frame body format with the following figure:

Category Action Value

Channel Switch Mode

New Regulatory

Class

New Channel Number

Channel Switch Count

Mesh Channel Switch Parameters

element

Octets: 1 1 1 1 1 1 6

Figure 7-101h4—Extended Channel Switch Announcement frame body format

Modify the last pargraph of 7.4.7.6 as shown below:

The Channel Switch Mode, New Regulatory Class, New Channel Number and Channel Switch Count remaining fields are as described in the Extended Channel Switch Announcement element (see 7.3.2.53 (Extended Channel Switch Announcement element(11y))).

Mesh Channel Switch Parameters element is defined in 7.3.2.100 (Mesh Channel Switch Parameters element). This element is present when a mesh STA performs MBSS channel switch. The Mesh Channel Switch Parameters element is not used for channel switch other than the MBSS channel switch.

7 Mesh Resource Coordination Action frame details

Delete row containing “Mesh Channel Switch Announcement” from Table s23 Mesh Resource Coordination Action field values also update the last row as shown below:document.doc

T Mesh Resource Coordination Action field valuesdocument.doc

Action field value Description

0 Congestion Control Notification

1 MCCA Setup Request

2 MCCA Setup Reply

3 MCCAOP Advertisement Request

4 MCCAOP Advertisements


March 2010 doc.: IEEE 802.11-10/0205r2

5 MCCAOP Reservation Teardown

6 TBTT Adjustment Request

7 TBTT Adjustment Response

8 Mesh Channel Switch Announcement

89-255 Reserved

7.4.18.10 Mesh Channel Switch Announcement frame format

Delete 7.4.18.10 Mesh Channel Switch Announcement frame format completely:

Mesh Channel Switch Announcement frame formatThe Mesh Channel Switch Announcement frame is transmitted by a mesh STA to signal a channel switch as described in 11C.6 (MBSS channel switching). This frame is transmitted using group addresses or individual addresses. The format of the Mesh Channel Switch Announcement frame body is shown in Mesh Channel Switch Announcement frame bodydocument.doc.

T Mesh Channel Switch Announcement frame bodydocument.doc


1 Category

2 Action

3 Mesh Channel Switch Announcement element

The Category field is set to the value in Error: Reference source not found for category Mesh Resource Coordination.

The Action field is set to the value in Mesh Resource Coordination Action field values also update the last row asshown below:document.doc representing Mesh Channel Switch Announcement.

The Mesh Channel Switch Announcement element is set as described in Error: Reference source not found.


March 2010 doc.: IEEE 802.11-10/0205r2

10.3.15 Channel switch

10.3.15.1 MLME-CHANNELSWITCH.request

10.3.15.1.1 Function

This primitive requests a switch to a new operating channel.

10.3.15.1.2 Semantics of the service primitive

Modify 10.3.15.1.2 as shown below:

The primitive parameters are as follows:MLME-CHANNELSWITCH.request(

Mode,Channel Number,Secondary Channel Offset,Channel Switch Count,Mesh Channel Switch Parameters,VendorSpecificInfo)

Modify the row containing Channel Switch Count in the untitled table defining the primitive parameters in 10.3.15.1.2 as shown:

Name Type Valid range Description

Channel SwitchCount

IntegeAs defined in 7.3.2.20 (Channel Swich Announcement element)r

As defined in 7.3.2.20 (Channel Swich Announcement element)0–255

Specifies the number of TBTTstime period until thechannel switch event, as described for thein 7.3.2.20 (Channel Switch Announcement element).

Insert the following new row to the untitled table defining the primitive parameters in 10.3.15.1.2 as shown:



As defined in Mesh Channel Switch Paramters element 7.3.2.100


Specifies MBSS Channel Switch Parameters use by a mesh STA. This parameter is present if the dot11MeshActivated is true; otherwise the parameter is not present.


March 2010 doc.: IEEE 802.11-10/0205r2


10.3.15.1.4 Effect of receipt

On receipt of this primitive, the MLME schedules the channel switch event and announces this switch to other STAs in the BSS using the Channel Switch Announcement frame or element. A mesh STA shall include the Mesh Channel Switch Parameters element in the Beacon and Probe response frames if Beacon and Probe response frame s contain Channel Switch Announcement element. The MLME ensures the timing of frame transmission takes into account the activation delay. The actual channel switch can be achieved at the appropriate time through the MLME-PLME interface using the PLME-SET primitive of the dot11CurrentFrequency MIB attribute.


10.3.15.3 MLME-CHANNELSWITCH.indication


This primitive indicates that a channel switch announcement has been received from a peer entity.


The primitive parameters are as follows:MLME-CHANNELSWITCH.indication(

Peer MAC Address,Mode,Channel Number,Secondary Channel Offset,Channel Switch Count,Mesh Channel Switch Parameters,VendorSpecificInfo)



Channel SwitchCount







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This primitive is used to schedule an accepted channel switch.


The primitive parameters are as follows:MLME-CHANNELSWITCH.response(

Mode,Channel Number,Secondary Channel Offset,Channel Switch Count,Mesh Channel Switch Parameters,VendorSpecificInfo

)



Channel SwitchCount







As defined in Mesh Channel Switch Paramters


Specifies MBSS Channel Switch Parameters use by a mesh STA. This parameter is present if the dot11MeshActivated is true; otherwise


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element 7.3.2.100

the parameter is not present.

10.3.35 Extended channel switch announcement(11y)

The following MLME primitives support the signaling of extended channel switch announcement.

10.3.35.1 MLME-EXTCHANNELSWITCH.request(11y)


10.3.35.1.1 Function(11y)

This primitive requests that an Extended Channel Switch Announcement frame be sent by an AP or a mesh STA in an MBSS.


10.3.35.1.2 Semantics of the service primitive(11y)

The primitive parameters are as follows:MLME-EXTCHANNELSWITCH.request (

Mode,RegulatoryClass,ChannelNumber,ChannelSwitchCount,Mesh Channel Switch Parameters,VendorSpecificInfo)



ChannelSwitch-Count

As defined in 7.3.2.53

(Extended Channel Swich

Announcement

element)Integer

As defined in 7.3.2.53 (Extended

Channel Swich Announcement element)0..255

Specifies the number of TBTTstime period until the channel switch event, as described forin 7.3.2.53the Extended Channel Switch Announcement element.



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10.3.35.1.3 When generated(11y)

This primitive is generated by the STA management entity (SME) to schedule an extended channel switch and announce this switch to peer entities in the BSS, or MBSS.request that an Extended Channel Switch Announcement frame be sent to a STA that is associated to the AP.


10.3.35.3 MLME-EXTCHANNELSWITCH.indication(11y)

10.3.35.3.1 Function(11y)

This primitive indicates that an Extended Channel Switch Announcement frame was received from an APhas been received from a peer entity.



The primitive parameters are as follows:MLME-EXTCHANNELSWITCH.indication (

Peer MAC Address,Mode,RegulatoryClass,ChannelNumber,ChannelSwitchCount,Mesh Channel Switch Parameters,VendorSpecificInfo)



ChannelSwitch-



Specifies the number of TBTTstime period until the


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Count


Announcement

element)Integer


channel switch event, as described forin 7.3.2.53the Extended Channel Switch Announcement element.







10.3.35.4 MLME-EXTCHANNELSWITCH.response(11y)

10.3.35.4.1 Function(11y)

This primitive is used to schedule an accepted extended channel switch.



The primitive parameters are as follows:

MLME-EXTCHANNELSWITCH.response (Mode,RegulatoryClass,ChannelNumber,ChannelSwitchCount,Mesh Channel Switch Parameters,VendorSpecificInfo)



ChannelSwitc As defined in As defined in Specifies the number of


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h-Count

7.3.2.53 (Extended Channel Swich

Announcement

element)Integer

7.3.2.53 (Extended Channel Swich Announcement element)0..255

TBTTstime period until the channel switch event, as described forin 7.3.2.53the Extended Channel Switch Announcement element.







10.3.40 Protected Extended Channel Switch Announcement(11w)

The following MLME primitives support the signaling of Protected Extended Channel Switch Announcement.

10.3.40.1 MLME-PDEXTCHANNELSWITCH.request(11w)


10.3.40.1.1 Function(11w)

This primitive requests that a Protected Extended Channel Switch Announcement frame be sent by an AP or a mesh STA in MBSS.


10.3.40.1.2 Semantics of the service primitive(11w)


MLME-PDEXTCHANNELSWITCH.request (Mode,RegulatoryClass,ChannelNumber,ChannelSwitchCount,Mesh Channel Switch Parameters,VendorSpecificInfo

)


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ChannelSwitch-Count



Announcement

element)Integer











10.3.40.1.3 When generated(11w)

This primitive is generated by the SME to request that a Protected Extended Channel Switch Announcement frame be sent to a STA that is associated to the AP or to a peer mesh STA in the MBSS.

10.3.40.3 MLME-PDEXTCHANNELSWITCH.indication(11w)


10.3.40.3.1 Function(11w)

This primitive indicates that a Protected Extended Channel Switch Announcement frame was received from an AP or from a peer mesh STA.




MLME-PDEXTCHANNELSWITCH.indication (


March 2010 doc.: IEEE 802.11-10/0205r2

Peer MAC Address,Mode,RegulatoryClass,ChannelNumber,ChannelSwitchCount,Mesh Channel Switch Parameters,VendorSpecificInfo)



ChannelSwitch-Count



Announcement

element)Integer










10.3.40.4 MLME-PDEXTCHANNELSWITCH.response(11w)

10.3.40.4.1 Function(11w)

This primitive is used to schedule an accepted extended channel switch.




MLME-PDEXTCHANNELSWITCH.response(Mode,


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RegulatoryClass,ChannelNumber,ChannelSwitchCount,Mesh Channel Switch Parameters,VendorSpecificInfo

)



ChannelSwitch-Count



Announcement

element)Integer











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1 DFS procedures

Change the fourth paragraph in 11.9 as follows:

— A STA shall set dot11SpectrumManagementRequired to TRUEtrue before associating withjoining an infrastructure BSS or , IBSS or becoming a member of an MBSS in which the Spectrum Management bit is set to 1 in the Capability Information field in Beacon frames and Probe Response frames received from the infrastructure BSS or , IBSS or MBSS BSS .

11.9.7 Selecting and advertising a new channel

1 Selecting and advertising a new channel

Insert the following new subclause after 11.9.7.2:

E clause numbering based on 11n adding 11.9.7.3. The following clause should appear immediately after 11.9.7.2 (i.e., before 11n subclause 11.9.7.3)

1 Selecting and advertising a new channel in an MBSS Channel Switching

11.9.7.2a.1 General

The mesh channel switch may be triggered by the need to avoid interference to a detected radar signal, or to reassign mesh STA channels to ensure the MBSS connectivity.

A mesh STA may make use of the information in Supported Channel elements, Supported Regulatory Classes elements and the results of measurements undertaken by the mesh STAs in the MBSS to assist the selection of the new channel. The algorithm to choose a new channel is beyond the scope of this standard, but shall satisfy applicable regulatory requirements, including uniform spreading rules and channel testing rules.

If a mesh STA detects the need to switch the channel, the mesh STA should inform channel switch decision to peer mesh STAs to which a mesh link has been established.

Once the mesh STA identifies the candidate channel to switch its channel to, it shall initiate the Channel Switch protocol described in 11C.6 (MBSS channel switching).

A 20/40 MHz MBSS may be changed to a 20 MHz MBSS and a 20 MHz MBSS may be changed to a 20/40 MHz MBSS.

When an MBSS switches from a 20/40 MHz MBSS to a 20 MHz MBSS, some MCCAOP may need to be deleted to make sure that the MAF of each mesh STA does not exceed its MAF Limit.

When an MBSS switches from a 20 MHz MBSS to a 20/40 MHz MBSS or switches from a 20/40 MHz MBSS to a 20 MHz MBSS, a mesh STA may need to do path maintenance to find an optimized path.


March 2010 doc.: IEEE 802.11-10/0205r2

In the following subclauses Mesh Channel Switch Announcement refers to Mesh Channel Switch Parameters element together with Channel Switch Announcement element or Extended Channel Switch Announcement element.

11.9.7.2a.2 Initiating MBSS Channel Switch

A mesh STA shall not initiate a new channel switch attempt if there is an ongoing channel switch attempt by this mesh STA.

A mesh shall inform each of the peer mesh STAs that the mesh STA is moving to a new channel while maintaining mesh peerings by advertising the switch using Channel Switch Announcement elements together with Mesh Channel Switch Parameters element in Beacon frames, Probe Response frames, and Channel Switch Announcement frames until the intended channel switch time. The channel switch should be scheduled so that all mesh STAs in the MBSS, including mesh STAs in power save mode, have the opportunity to receive at least one Channel Switch Announcement element before the switch.

The fields in the Channel Switch Announcement element shall be set as follows. The Channel Switch Count field shall be set to the time period until the mesh STA sending the Channel Switch Announcement element switches to the new channel so that the channel switch attempt can be propagated throughout the MBSS before the mesh STA leaves the channel. The Channel Switch Mode field is reserved. The New Channel Number field shall be set to the number of the channel to which the mesh STA is moving.

The fields in the Mesh Channel Switch Parameters element shall be set as follows. The Precedence Value field shall be set to a random value selected from a uniform distribution in the range from 0 to 65535. The mesh STA may force mesh STAs in the MBSS to stop transmissions of frames except frames containing Channel Switch Announcement element until the channel switch takes place by setting the Transmit Restrict subfield of the Flags field to 1. The Reason subfield in the Flags field shall be set to 1 to indicate that content of the Reason Code field is valid. The Initiator subfield of the Flag field shall be set to 1. The Time to Live field should be set to the maximum number of hops (e.g., dot11MeshHWMPnetDiameter) this Channel Switch attempt is intended for.

11.9.7.2a.3 Processing Channel Switch Announcement

Upon receipt of a Channel Switch Announcement, a mesh STA shall not accept and shall not process the received Channel Switch Announcement element or Extended Channel Switch Announcement element if any of the following is true:

— The Mesh Channel Switch Parameters element is not present in the received frame containing Channel Switch Announcement element or Extended Channel Switch Announcement element.

— The Time to Live field in the received Mesh Channel Switch Parameters element is 0.

— A mesh Channel switch is already running and mesh STA has not yet moved into the new channel and/or regulatory class and the Current Precedence value is greater than or equal to the received Precedence Value.

A mesh STA that receives a Channel Switch Announcement element may choose not to perform the specified switch, but to take alternative action. For example, it may choose to move to a different MBSS.

When mesh STA accepts a channel switch, it shall adopt information received in Channel Switch Announcement element and Mesh Channel Switch Parameters element. The mesh STA shall schedule the Channel Switch as per this information. If the Time to Live field value in the received Mesh Channel Switch Parameters element is greater than one, the mesh STA shall transmit Channel Switch Announcement frame and shall include Channel Switch Announcement element together with Mesh Channel Switch Parameters element in the


March 2010 doc.: IEEE 802.11-10/0205r2

Beacon and Probe Response frames until the intended channel switch time. The fields in the Channel Switch Announcement shall be set to the values identical to those in the received Channel Switch Announcement frame. The fields in the Mesh Channel Switch Parameters element shall be set to the values identical to those in the received Mesh Channel Switch Parameters element, except for the Time to Live field, Initiator field and the Transmit Restrict subfield of the Flags field. The Time to Live field shall be set to the received Time to Live field minus 1. The Initiator field shall be set to 0. The Transmit Restrict field shall be set to 1 when the mesh STA requires neighboring mesh STAs not to transmit further frames not containing Channel Switch Announcement element on the current channel until the scheduled channel switch. The Transmit Restrict subfield shall be set to 0 otherwise.

It is possible that a channel switch is not successful in moving all the mesh STAs in MBSS to the new operating channel. Transitioning to a new channel does not tear down mesh peerings and existing mesh peerings may be maintained in the new operating channel.

After moving into new operating channel the mesh STA shall perform CCA until a frame sequence is detected by which it can correctly set its NAV, or until a period of time equal to the ProbeDelay has transpired.

11.9.7.2a.4 Channel Switch across a regulatory class

When dot11RegulatoryClassesImplemented is true and the mesh STAs is capable of operating in multiple regulatory classes, the mesh STA shall include the Supported Regulatory Classes element within its Mesh Peering Open frames. The Supported Regulatory Classes element announces the regulatory classes that the mesh STA supports.

When dot11RegulatoryClassesImplemented is true, mesh STAs may switch from the operating channel to a channel in a different regulatory class.

Modify11.9.7a as follows:

11.9.7a Channel Switch Announcement element operation(#29)

A Channel Switch Mode set to 1 means that the STA in a BSS to which the frame containing the element is addressed shall transmit no further frames within the BSS until the scheduled channel switch. A STA in an IBSS may treat a Channel Switch Mode field set to 1 as advisory. A Channel Switch Mode set to 0 does not impose any requirement on the receiving STA. The Channel Switch Mode field is reserved in an MBSS.

11.9a Extended channel switching (ECS)(11y)

Modify 11.9a.1 as follows:

11.9a.1 General(11y)

This subclause describes ECS procedures that can be used to change BSS operation in channel frequency and Channel bandwidth. Enabling STAs (see 11.11 (DSE procedures(11y))), APs, and DFS owners, and mesh STAs are each STAs that may construct and transmit frames containing Extended Channel Switch Announcement elements when dot11ExtendedChannelSwitchEnabled(Ed) is true.


March 2010 doc.: IEEE 802.11-10/0205r2

Insert the following new subclause at the end of 11.9a.3.2 :

11.9a.3.3 Selecting and advertising a new channel in an MBSS

A mesh STA may make use of the information in the Supported Channels element, Supported Regulatory Classes element, and the results of measurements undertaken by the this mesh STA and other mesh STAs in the MBSS to assist the selection of the new channel and/or regulatory class.

The mesh STA that advertises a channel switch shall follow the rules defined in 11.9.7.2a (MBSS Channel Switching) with the following extensions:

a) If a mesh STA is switching to a different regulatory class, then the mesh STA shall use the Extended Channel Switch Announcement element and frame. Alternatively, both the Extended Channel Switch Announcement and the Channel Switch Announcement elements and frames may be used when Channel Switch Announcement elements and frames are permitted for operation in the band signified by the new regulatory class.

b) If a mesh STA is switching to a new channel within the same regulatory class, then the mesh STA shall send the Channel Switch Announcement element and frame, or both the Extended Channel Switch Announcement and the Channel Switch Announcement elements and frames.

c) If both the Extended Channel Switch Announcement and the Channel Switch Announcement elements are transmitted in Public Action frames, they shall be sent in separate frames.

d) The Extended Channel Switch Announcement element shall be included in the Beacon and Probe Response frames until the intended channel switch time.

Insert the following new subclause immediately after 11C and renumber as required:

11C.1a Mesh Network Dependencies

When dot11MeshActivated is true, the STA is a mesh STA and dot11ExtendedChannelSwitchEnabled and dot11SpectrumManagementRequired shall be true.

11C.6 MBSS channel switching

Delete 11C.6 subclause:


March 2010 doc.: IEEE 802.11-10/0205r2

MBSS channel switching

General

This subclause describes channel switching procedures that can be used to satisfy regulatory requirements. The procedures may also be useful for other purposes. The mesh channel switch may be triggered by the need to avoid interference to a detected radar signal, or to reassign mesh STA channels to ensure MBSS connectivity.

Channel Switch protocol

This subclause describes the procedure used for a mesh STA to initiate a channel switch. To resolve conflicts in case more than one mesh STA initiates a channel switch concurrently, each mesh STA utilizes a Mesh Channel Switch Timer and a Current Precedence Value. Their usage is explained later in this subclause.

A mesh STA that determines the need to switch the channel shall initiate a channel switch attempt and transmit a Mesh Channel Switch Announcement frame to each of its peer mesh STAs to announce its intent. The Mesh Channel Switch Announcement frame may be transmitted using individually or group addressed frames. The mesh STA shall include the Mesh Channel Switch Announcement element in its Beacon frames and Probe Response frames during the channel switch process.

The fields in the Channel Switch Announcement shall be set as follows. The Channel Switch Count field is set to a value in the range from 0 to 65535, representing the duration (in TUs) until the mesh STA switches to the new channel so that the channel switch attempt can be propagated throughout the MBSS before the mesh STA leaves the channel. The Precedence Value field is set to a random value selected from a uniform distribution in the range from 0 to 65535. The random value shall be selected in a manner that minimizes the probability of mesh STAs generating the same number, even when those mesh STAs are subjected to the same initial conditions.

The fields in the Channel Switch Mode field are set to indicate the attributes of this channel switch attempt. The Silence field is set to 1 when the mesh STA requests neighboring mesh STAs not to transmit further data frames on the current channel until the scheduled channel switch. The Silence field is set to 0 otherwise. The Initiator field is set to 1. The Reason field is set to 1 when this channel switch attempt is triggered by the spectrum usage rule imposed by the regulatory domain such as radar detection, and set to 0 otherwise.


March 2010 doc.: IEEE 802.11-10/0205r2

The New Regulatory Class field in the Channel Switch Announcement frame is set to the number of the regulatory class after the channel switch. The regulatory class numbers are defined in Annex J. The New Channel Number field is set to the number of the channel to which the mesh STA is moving.

A mesh STA that initiates the channel switch attempt shall initialize its Mesh Channel Switch Timer to the value that is contained in the Channel Switch Count field in the Mesh Channel Switch Announcement element. The mesh STA shall set its Current Precedence Value to the Precedence Value field in the Mesh Channel Switch Announcement frame. A channel switch attempt is identified by these parameters. When the Mesh Channel Switch Timer reaches zero, the mesh STA shall switch to the new channel. On the new channel, the mesh STA shall no longer include the Channel Switch Announcement in its Beacon and Probe Response frames.

A mesh STA that receives a Mesh Channel Switch Announcement and that does not have its Mesh Channel Switch Timer set shall act as follows. The decision to accept a Mesh Channel Switch Announcement is beyond the scope of this standard. The information in the Mesh Channel Switch Mode in the received Mesh Channel Switch Announcement may be used in deciding whether to accept or ignore this channel switch attempt. A mesh STA that receives a Mesh Channel Switch Announcement and that has its Mesh Channel Switch Timer set shall act as follows. In case the Precedence Value in the received Mesh Channel Switch Announcement frame is lower than or equal to its Current Precedence Value, the received Mesh Channel Switch Announcement shall be ignored. In case the Precedence Value in the received Mesh Channel Switch Announcement frame is greater than its Current Precedence Value, it may accept the channel switch. The decision to accept a Mesh Channel Switch Announcement is beyond the scope of this standard. The information in the Mesh Channel Switch Mode may also be used for this decision.

In case the mesh STA accepts a channel switch, it shall transmit a Channel Switch Announcement frame to each of its peer mesh STAs and include the Mesh Channel Switch Announcement element in its Beacon and Probe Response frames. The fields in the Mesh Channel Switch Announcement are set to values identical to those in the received Mesh Channel Switch Announcement frame, except for the Initiator field and the Silence field. The Initiator field is set to 0. The Silence field is set to 1 when the mesh STA requires neighboring mesh STAs not to transmit further data frames on the current channel until the scheduled channel switch. The Silence field is set to 0 otherwise. Upon receipt of the Channel Switch Announcement, the mesh STA shall set its Current Precedence Value equal to the Precedence Value of the received Mesh Channel Switch Announcement. It shall set its Mesh Channel Switch Timer equal to the value of the Channel Switch Count and count it down. When the timer reaches zero, the mesh STA shall switch to the new channel. On the new channel, the mesh STA does not include the Channel Switch Announcement in its Beacon and Probe Response frames.

A mesh STA with its Mesh Channel Switch Timer set shall not initiate a new channel switch attempt.


March 2010 doc.: IEEE 802.11-10/0205r2

The channel switch attempt initiator should set the Channel Switch Count so that its channel switch attempt can be propagated throughout the mesh before it leaves the channel.

It is possible that a channel switch is not successful in moving all neighbor peer mesh STAs to the new channel. Transitioning to a new channel does not tear down mesh peering and existing mesh peerings may be maintained in the new channel.

Channel Switch across a regulatory class

When dot11RegulatoryClassesImplemented is true and the mesh STAs is capable of operating in multiple regulatory classes, the mesh STA shall include the Supported Regulatory Classes element within its Mesh Peering Open frames. The Supported Regulatory Classes element announces the regulatory classes that the mesh STA supports.

When dot11RegulatoryClassesImplemented is true, mesh STAs may switch from the operating channel to a channel in a different regulatory class. However, the mesh STA that initiates the channel switch attempt across the regulatory class shall verify that all of its neighboring peer mesh STAs support the new regulatory class by checking neighbor mesh STA's Supported Regulatory Classes element.

NOTE—It is possible that a channel switch is not successful in moving all neighbor peer mesh STAs to the new channel, since the mesh STA that initiates the channel switch attempt does not know if the 2-hop neighbor mesh STAs support the new regulatory class. The channel switch across the regulatory class is considered to be used as the last choice in the selection of a new channel.


March 2010 doc.: IEEE 802.11-10/0205r2

A PICS proforma - IEEE Std 802.11, 2007

A MAC protocol

A MAC frames

Delete the row containing FT41 Mesh Channel Switch Announcement and renumber all subsequent entries of the table in A.4.4.2:

Item Protocol Capability Reference Status Support

FT40 TBTT Adjustment Request frame

Error: Reference source not found

MP4.2.2:M Yes No N/A

FT41 Mesh Channel Switch Announcement frame

Mesh Channel Switch Announcement frame format

MP7.1:M Yes No N/A

Delete the row containing FR41 Mesh Channel Switch Announcement and renumber all subsequent entries of the table in A.4.4.2:


FR40 TBTT Adjustment Request frame

Error: Reference source not found

MP4.2.2:M Yes No N/A

FR41 Mesh Channel Switch Announcement frame

Mesh Channel Switch Announcement frame format

MP7.1:M Yes No N/A

E numbering of following subclause based on TGu ending with A.4.22. A.4.23 is the first unused subclause.

A Mesh Protocol Capabilities

A General Mesh Support

Modify row containing MP7 as shown below of table A.4.23.1 Remove rows MP7.1 and MP7.2 of table A.4.23.1:


March 2010 doc.: IEEE 802.11-10/0205r2


MP6.3 Local rate control Error: Reference source not found

MP6:M Yes No N/A

MP7 MBSS channel selection 11.9.7 Selecting and advertising a new channel,11.9a.3 Selecting and advertising a new channel and/or regulatory class11C.6 MBSS channel switching

MP1:M Yes No N/A

*MP7.1 Channel switch announcement

11C.6 MBSS channel switching

MP7:M Yes No N/A

MP7.2 Channel switch execution 11C.6 MBSS channel switching

MP7:M Yes No N/A

MP8 Mesh Power Management Error: Reference source not found

MP1:O Yes No N/A


doc.: ieee 802.11-10/0205r2 · web view802.11 tgs submission on mesh channel switch announcement...

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