* Refer to the Summary Slides 1 for Details on the Resolved Comments. *

March 2007 doc.: IEEE 802.11-07/0302r1IEEE P802.11 Wireless LANsUpdated Texts for Frame Addressing and Forwarding in a Mesh NetworkDate: 2007-03-14Author(s): Name Company Address Phone email Kyeong Soo 1060 East Brokaw Road, MS STMicroelectronics +1-408-451-8137 [email protected] (Joseph) Kim 212, San Jose, CA 95131 / [email protected] 2-17-1 Higashi-gotanda, Kazuyuki Sony Corporation Shinagawa-ku, Tokyo, 141-0022 +81-3-6409-3201 [email protected] Sakoda Japan W. Steven 2111 NE 25th Ave, Hillsboro, [email protected] Intel Corp. +1-503-264-8036 om Conner OR 97124 Hrishikesh 1064 Greenwood Blvd., Suite Motorola Inc. +1-407-562-4093 Hrishikesh.Gossain@mo Gossain -400, Lake Mary, FL: 32746 torola.com Guenael 1064 Greenwood Blvd, Lake Motorola +1-407-562-4050 Guenael.Strutt@motorol Strutt Mary, FL 32746 a.com Jorjeta 16795 Lark Ave., Firetide +1-408-355-7215 [email protected] Jetcheva Los Gatos, CA 95032 Siemens AG, Otto-Hahn-Ring 6 81730 +49-89-636- Michael Bahr Corporate [email protected] Munchen Germany 49926 Technology 555 Del Rey Ave, Sunnyvale, Malik Audeh Tropos +1-408-331-6834 [email protected] CA 94085 James 5753 W. Las Positas Blvd. Trapeze Networks +1-925-474-2233 jmurphy@trapezenetwor Murphy Pleasanton, CA 94588 ks.com NextHop 825 Victors Way Susan Hares +1-734-222-1610 [email protected] Technologies Ann Arbor, MI 48108 10 Harrlerbergweg 110-1CH Jan Kruys Cisco Systems +31 203572447 [email protected] Amsterdam, NetherlandsAbstract This document provides updated texts for frame addressing and forwarding in a mesh network in Clause 7.1.3.5a.4 and 11A.2.4, which resolve the following CIDs:25, 26, 27, 165, 168, 391, 392, 393, 394, 395, 397, 480, 487, 488, 489, 490, 510, 751, 752, 753, 754, 755, 1137, 1424, 1829, 1830, 1894, 1907, 2199, 2200, 2229, 3187, 3511, 3563, 3582, 3584, 3586, 3587, 3588, 3857, 3858, 4223, 4226, 4227, 4308, 4372, 4375, 4378, 4379, 4657, 4658, 4825, 4828, 4859, 5325, 5326, 5657Notice: 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. heSubmission Chair <[email protected]> as early as possible, inpage written 1 or electronic form, if patentedKyeong technology Soo (Joseph) (or technology Kim, under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If youSTMicroelectronics have questions, contact the IEEE Patent Committee Administrator at <[email protected]>. March 2007 doc.: IEEE 802.11-07/0302r1CIDs resolved: 25, 26, 27, 165, 168, 391, 392, 393, 394, 395, 397, 480, 487, 488, 489, 490, 510, 751, 752, 753, 754, 755, 1137, 1424, 1829, 1830, 1894, 1907, 2199, 2200, 2229, 3187, 3511, 3563, 3582, 3584, 3586, 3587, 3588, 3857, 3858, 4223, 4226, 4227, 4308, 4372, 4375, 4378, 4379, 4657, 4658, 4825, 4828, 4859, 5325, 5326, 5657(* Refer to the summary slides [1] for details on the resolved comments. *)Proposed resolutionReplace the second paragraph of subclause 7.1.3.5a.5 with the new one provided below:Address 5 and Address 6 may be used to transport the addresses of source and destination end points in cases where either (or both) of the end points are not MPs at the beginning or end of a single mesh path. This is useful, for example, in the following cases: When the end points of IEEE 802 communication are non-mesh, proxied entities which communicate over a mesh via proxy MPs. When the end points are MPs communicating with each other via a root MP in HWMP proactive tree building mode, where two distinct mesh paths are used (the first path being from the source MP to the root MP and the second path being from the root MP to the destination MP).Details on the usage of these optional address fields are given in Clause 11A.3.4 as a part of the description of frame addressing and forwarding in a mesh network.Submission page 2 Kyeong Soo (Joseph) Kim, STMicroelectronics March 2007 doc.: IEEE 802.11-07/0302r1Replace subclause 11A.3.4 with the new one below (note that the texts provided depend on the definitions of two new terminologies “Proxy MP” and “Proxied Entities”, which are introduced in a separate contribution [2]):11A WLAN Mesh Networking11A.1 Mesh discovery and peer link establishment11A.2 Mesh link security11A.3 Mesh path selection and forwarding framework11A.3.1 Overview11A.1.1 Extensible path selection framework11A.3.2 Path selection metrics and protocols11A.1.2 Frame addressing and forwarding in a mesh network11A.1.2.1 OverviewMesh Data frames and Mesh Management frames are designed to support multi-hop frame forwarding in a mesh network using the Mesh Header described in Clause 7.1.3.5.a. In this subclause, addressing and forwarding of these frames are described.Figure sXX shows the valid combinations of address fields in Mesh Data frames and Mesh Management frames along with the corresponding values of the “To DS”, “From DS”, and “AE Flag” fields.Supported To From AE Address Address Address Address Address Address Frames DS DS Flag 1 2 3 4 5 6 Mesh Data, 1 1 0 RA TA DA = SA = Not Not Mesh Mesh DA Mesh SA Present Present Management Mesh Data 1 1 1 RA TA Mesh DA Mesh SA DA SAFigure sXX: Valid address field usage for Mesh Data frames and Mesh Management frames.Address 1 and Address 2 correspond to the MP receiver address (RA) and the MP transmitter address (TA) for a particular mesh link. Address 3 and Address 4 correspond to the destination and source endpoints of a mesh path. The AE flag indicates the existence of the optional address extension field including Address 5 and Address 6 in the Mesh Header which correspond to the end-to-end destination address (DA) and source address (SA) in the following cases:Submission page 3 Kyeong Soo (Joseph) Kim, STMicroelectronics March 2007 doc.: IEEE 802.11-07/0302r1 When the end points of IEEE 802 communication are non-mesh, proxied entities which communicate over a mesh via proxy MPs. When the end points are MPs communicating with each other via a root MP in HWMP proactive tree building mode, where two distinct mesh paths are used (the first path being from the source MP to the root MP and the second path being from the root MP to the destination MP).The term source MP refers to the first MP that transmits a frame on a mesh path. A source MP may be an MP that is the original source of a frame or a proxy MP that receives a frame from an entity outside of the mesh and translates and forwards the frame on a mesh path. The address of the source MP is referred to as the Mesh SA. The term destination MP refers to the final MP on a mesh path. A destination MP may be an MP that is the final destination of a frame or an MP that receives a frame from a mesh path and translates and forwards the frame on another mesh path or to an entity outside of the mesh. The address of the destination MP is referred to as the Mesh DA.Figure sYY illustrates example addressing of a Mesh Data frame transmitted and forwarded on a mesh path from an MAP to an MPP where the original source is an 802.11 STA associated with the MAP and the final destination is an entity outside of the mesh that is reachable via the MPP.SA Mesh SA Mesh DA DA802.11 MAP MP MPP STA STA link link link link mesh path End-to-end 802 communicationFigure sYY: Example Addressing for a Mesh Data frame transmitted and forwarded on a mesh path from an MAP to an MPP. Details on how these address mappings work in forwarding processing are described in 11A.3.4.2 and 11A.3.4.3. 11A.1.2.2 Addressing and Forwarding of Unicast Frames 11A.1.2.2.1 At Source MPsIn cases where both end points are MPs at the beginning and end of a single mesh path, the source MP shall use 4- address frames (with AE flag set to 0) where the four address fields in the header are set as follows: Address 1: The address of the next-hop MP (toward the Destination MP according to forwarding information) Address 2: The address of the Source MP Address 3: The address of the Destination MP Address 4: The address of the Source MPIn cases where either (or both) of the end points is not an MP at the beginning or end of a single mesh path, the source MP at the beginning of the mesh path shall use 6-address frames (with AE flag set to 1) where the mesh address extension field in the Mesh Header carries the addresses of the end points, as follows: Submission page 4 Kyeong Soo (Joseph) Kim, STMicroelectronics March 2007 doc.: IEEE 802.11-07/0302r1 Address 1: The address of the next-hop MP (toward the last MP of the mesh path, according to forwarding information) Address 2: The address of the source MP at the beginning of the mesh path Address 3: The address of the destination MP at the end of the mesh path Address 4: The address of the source MP at the beginning of the mesh path Address 5: The address of the destination end point (may be the same as Address 3 if the destination is the MP at the end of the mesh path) Address 6: The address of the source end point (may be the same as Address 4 if the source is the MP at the beginning of the mesh path)The Source MP shall set the Mesh E2E Sequence Number field in the Mesh Header to a value from a single modulo- 65536 counter that is incrementing by 1 for each new frame. The TTL field in the Mesh Header shall be set to the value of dot11MeshTTL.11A.1.2.2.2 At Intermediate and destination MPsOn receipt of a unicast frame, an MP shall decipher it and check it for authenticity. If it is not from a peer MP, the frame shall be silently discarded.The MP shall then check to see whether the Mesh DA in Address 3 field is known; if it is an unknown address, the MP may either silently discard the frame or trigger a path discovery procedure depending on the path selection protocol that is currently active in the mesh.If Address 3 does not match the MP’s own address, but is a known MAC addresses in the forwarding information, the MP shall decrement the TTL field in the Mesh Header. If zero has been reached, the frame shall be discarded. Otherwise, the MP shall forward the frame by setting the Address 1 field to the MAC address of the next hop MP as determined from the forwarding information and the TA field to its own MAC address and queueing the frame for transmission.If Address 3 matches the MP’s own MAC address, then the MP shall check the AE flag in the Mesh Header field and take the following actions based on its value: If the AE flag is set to 0, indicating this MP is the final destination of the frame, the MP shall process and send it to an upper layer. By the pair of source MP Address (identified by Address 4 field of the MAC header) and Mesh E2E Sequence Number, the destination MP may detect duplicate frames. Duplicate frames may be discarded. If the AE flag is set to 1: o If the current MP is a proxy MP for non-mesh, proxied entities, the MP shall first check whether or not the destination address (DA) in Address 5 field is one of the addresses of its proxied entities. If the destination address is the address of one of its proxied entities, the MP shall translate the frame to the corresponding format and queue it for transmission to the final destination. o If the current MP is a root MP (in HWMP proactive tree building mode), the MP shall check whether the DA in Address 5 field is one of its known addresses or not:. If the DA in Address 5 corresponds to an MP, the MP shall reformat the frame as a 4- address frame with Address 3 field set to the DA, Address 4 set to the source end-point address, Address 1 set to the next-hop MP on the mesh path to the destination MP, and Submission page 5 Kyeong Soo (Joseph) Kim, STMicroelectronics March 2007 doc.: IEEE 802.11-07/0302r1Address 2 set to the root MP’s address. The MP shall then queue the frame for transmission.. If the DA in Address 5 corresponds to a non-mesh entity proxied by one of its known MPs, the MP shall update the Address 3 field to the address of the proxy MP, the Address 1 field to the next-hop MP on the mesh path to the proxy MP, and Address 2 to the root MP’s address. The MP shall then queue the frame for transmission.Note that in some cases, an MP could be both a proxy MP and a root MP. In such a case, the MP should follow both the steps described for the case that AE flag is set to 1.Also, note that during the forwarding process at intermediate MPs, the contents of the frame body are not changed.11A.1.2.3 Addressing and Forwarding of Broadcast Frames 11A.1.2.3.1 At Source MPsAn MP that is the source of a broadcast frame shall use a 4 address frame and set the Address 3 field to the broadcast address and the Address 2 and Address 4 fields to its own MAC address. If the frame is originally received by an MP from proxied entities (i.e., at MAPs/MPPs) with a broadcast address in the Address 1 (RA/DA) field the Source MP shall enable Mesh Address Extension by setting the AE flag to 1 and encode Address 5 to the broadcast address and Address 6 to the address of the proxied entity. It shall set the Address 3 field to the broadcast address and the Address 2 and Address 4 fields to its own MAC address.The Source MP shall set the TTL field in the Mesh Header to dot11MeshTTL in order to control the reachability of broadcast frames in terms of hop count. For example, if the TTL field is set to 1, frames are delivered to immediate neighbors only. Otherwise, the frames are broadcasted multiple hops, limited by the TTL value.The Source MP shall set the Mesh E2E Sequence Number field in the Mesh Header to a value from a single modulo- 65536 counter that is incrementing by 1 for each new frame. In order to increase the reliability of broadcast frame delivery, a Source MP may optionally transmit the same broadcast frame multiple times or break the frame in to multiple unicast frames to peer MPs with Address 1 set to each peer MP’s address and Address 3 set to the broadcast address.11A.1.2.3.2 At Intermediate and destination MPsOn receipt of a frame with Address 1 (RA) set to its MAC address or the broadcast MAC address and with Address 3 (DA/Mesh DA) set to the broadcast address, an MP deciphers the frame and checks for authenticity. If it is not from a peer MP, the frame shall be silently discarded. Otherwise, it shall be further processed as follows.The tuple of Address 4 (SA/Mesh SA) and Mesh E2E Sequence Number from the Mesh Header shall be used as a unique message signature for tracking broadcast frames. The MP checks whether the frame has previously been received. If this is the case, the frame shall be discarded. Otherwise, the MP shall retain the signature and continues processing the frame.The MP then decrements the TTL field in the Mesh Header field. If the TTL value has reached zero, the message shall not be forwarded to other MPs. Otherwise, the frame is queued for transmission to peer MPs in order to propagate this broadcast frame throughout the mesh. The transmission procedure of the broadcast frame is as described in the previous subclause.If the MP is a proxy MP, the MP shall transmit the frame to all its proxied entities outside the boundary of the mesh after translating the frame to the appropriate frame formats for proxied entities.Note that during the forwarding process at intermediate MPs, the contents of the frame body are not changed.Submission page 6 Kyeong Soo (Joseph) Kim, STMicroelectronics March 2007 doc.: IEEE 802.11-07/0302r111A.1.2.4 Multicast FramesOn transmission or receipt of a multicast frame, the same process used for broadcast forwarding in clause 11A.3.4.3 is applied for the multicast frame.The MP may implement multicast filtering technology to reduce multicast traffic flooding in the WLAN mesh network. This may be achieved, for example, by using the GARP Multicast Registration Protocol (GMRP) defined in IEEE802.1D. This filtering technology is beyond the scope of this specification.Support for special multicast capabilities is an implementation choice and requires invoking the extensibility feature of this standard.11A.1.2.5 Note on 7.2.3 Management Frames Management frames which utilize the normal 3-address management frame headers specified in Clause 7.2.3, such as Mesh Management Action frames (3-address action frames) described in Clause 7.4.6, are transmitted only one hop to immediate neighbor MPs.Note that in several cases, the reception and processing of a 3-address action frame leads to the transmission of a new action frame with the same type that may include an identical or a modified version of the contents from the IEs of the received action frame.Submission page 7 Kyeong Soo (Joseph) Kim, STMicroelectronics March 2007 doc.: IEEE 802.11-07/0302r1Insert the following at the end of dot11MeshPointConfig TABLE in Annex D: dot11MeshTTL OBJECT-TYPE SYNTAX INTEGER (0..255) MAX-ACCESS read-write STATUS current DESCRIPTION "This attribute shall specify the value of TTL field set at a source MP.” ::= { dot11MeshPointConfigEntry 4 }Submission page 8 Kyeong Soo (Joseph) Kim, STMicroelectronics March 2007 doc.: IEEE 802.11-07/0302r1References:[1] IEEE 11-07/0389r1 “Updated Texts for Frame Addressing and Forwarding in a Mesh Network (Summary)”, Mar. 2007. [2] IEEE 11-07/0337r0 “HWMP Proxy Frame Forwarding Comment Resolution”, Mar. 2007.Submission page 9 Kyeong Soo (Joseph) Kim, STMicroelectronics

* Refer to the Summary Slides 1 for Details on the Resolved Comments. *

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